Tektronix 453A Instruction Manual

' ΜΑΝUAL ι ι ι ι ι ι ι ι ι ι ι ι ι ι ι ι Se r ial Number Tektro n ix, Inc . 0 Ρ .Ο . Box 500 0 Beaverto n , Oregon 97005 " Phone : 644-0161 " Cables : Tektronix 070-1089-00 171

: warranted against . defective materials and workmanship for one year. Any ' . questions w ith respect, to the - warranty, mentioned above, shou ld- pe 'taken up with your Tektronix Field' Engineer or representative. All requests for repairq and . replacement parts should be directed to the Tektronix Fie ld Office or representative in Your area_ This procedure will assu re you' the fastest possible 'service. Please include the i nstrument Type (πr Part Numbery and Serial or Model Number with all requests for parts or Se rvice : Specifications and price change privileges reserved . Copyright © 1971 by Tektronix, Inc., Beaverton, Oregon . Printed in the United States of America. All rights reserved . Contents of this publication may not be reproduced i n any form without permission of th e copyright owner. U.S.A. :and foreign Tekt ronix products covered y U .S . and foreign patents, and/or patents pending .

SE CTION 1 453Α/R453A SPECI FICATIONS Page SECTION 2 OPERATING I NSTRU CTIONS (cont) Introd uction 1-1 I nput Cou pling 2-17 Table 1-1 E lectrical 1-1 Deflection Factor 2-17 V ertical Deflection System 1-1 D ual-Trace Operation 2-17 Triggeri ng (Α and Β Sweep) 1-3 Channel 1 Output and Cascaded Horizontal Deflection System 1-4 Operation 2-18 Calibrator 1-6 Algebraic Addition 2-19 Ζ Axis Input 1-7 Trigger Source 2-19 Outpu t Signals 1-7 Trigger Coup ling 2-20 Display 1-8 Trigger Slope 2-21 Power Supply 1-8 Trigger Level 2-21 Table 1-2 Environmental Characteristics 1-9 H igh-F requency Stability 2-21 Table 1-3 Physical 1-9 Α Swee p Triggered Light 2-21 Standard Accessories 1-10 Α Swee p Mode 2-21 Horizontal Sweep Rate 2-23 Swee p Magnificatio n 2-23 Mixed and Delayed Sweep 2-24 Χ-Υ Operation 2-27 SECTION 2 OPERATING I NSTRUCTIO NS Α and Β Gate 2-27 Intensity Modulation 2-27 Calibrator 2-27 ι ι ι ι ι ι ι ι General 2_1 Front Cover 2_7 App lications Operating Voltage 2_1 General 2-20 Operating Temperature 2-2 Peak to Peak Voltage Operating Position 2-2 Measureme nts-AC 2-28 Rackmoun ting 2-2 I nstantaneous Voltage Controls and Connectors 2-3 Measurements-DC 2-29 First-Time Operation 2-7 Comparison Measurements 2-30 Test Set-up Chart 2-11 Time-D u ration Measurements 2-31 General Operating Information Determining F requency 2-32 Simp lified Operating I nformation 2-11 R isetime Measureme nts 2-32 I ntensity Control 2-14 Time-Difference Measurements 2-33 Astigmatism Adjustment 2-14 Delayed Sweep Time Measurements 2-34 Graticule 2-14 Delayed Sweep Magnification 2-35 Trace Alignment Adjustment 2-15 Light F ilter 2_15 Displayed Complex Signals Beam F inder 2-15 Using Delayed Sweep 2-36 Vertical Chann el Selection 2-15 Pulse Jitter Measurements 2-37 Vertical Gain Adjustment 2-15 Delayed Trigger Generator 2-38 Step Attenuator Balance 2-16 Normal Trigger Generator 2-39 Signal Connections 2-16 Mu lti-Trace Phase Difference Loading Effect of the Measurements 2-39 Type 453Α/R453A 2-16 H igh Resol ution Phase Measurements 2-40 Coaxial Cable Considerations 2-16 Χ-Υ PhaseMeasurements 2-40 Ground Consideratio ns 2-17 Commo n-Mode Rejection 2-42

CI R CUIT DESCR IPTION SECTION 5 CAL I BRATION Introduction 3-1 Introduction 5-1 Block Diag ram 3-1 Tektro n ix Field Service 5-1 Circ u it Operation 3-3 Using Th is Procedure 5-1 Chann el 1 Vertical Preamp 3-4 Test Eq uipmen t Requ ired 5-1 Chann el 2 Vertical Preamp 3-6 Prelimi nary Control Settings 5-3 Vertical Switching 3-7 Part 1-Pe rformance Chec k Vertical Output Amp lifier 3-9 Introductio n 5-4 Trigger Preamp 3-10 Index to Part Ι -Performance Chec k 5-4 Α Trigger Generator 3-12 Α Sweep Generato r 3-16 Prelimi nary Procedure for Performance Check 5-5 Β Trigge r Ge nerator 3-19 Β Sweep Generator 3-21 Part I[-Adjustment Horizon tal Amplifier 3-23 Introduction 5-26 ' 2 Axis Amplifier 3-2ς Index to Part II-Adjustment 5-26 CRT Circu it 3-27 Preliminary Procedure for Low-Voltage Power Supp ly 3-28 Adjustme n t 5-26 Voltage Distrib ution 3-31 Calibrator 3-31 SE CTION 6 RACKMOUNTING SECTION 4 MAINTENANCE I ntroduction 6-1 Instrument Dimensions 6-1 Introduction 4-1 Rack Dimensions 6-1 Cover Removal 4-1 Slide-Out Tracks 6-1 Mounting Procedure 6-1 Preventive Maintenance Alternative Rear Mounting Methods 6-2 General 4-1 Removing or Installing the Instrumen t 6-3 Slide-Ou t Track Lubrication 6-3 Cleaning 4-1 Lu brication 4-2 Visual Inspection 4-2 Transistor Chec ks 4-2 SECTION 7 ELECTRICAL PA RTS LIST Recalibration 4-2 - Abbreviatio ns and Symbols Troubleshooting Parts Ord ering Informatio n Introduction 4-2 Index of Electrical Parts List Troubleshooting Aids 4-2 Electrical Parts List Troub leshooting Equ ipment 4-4 Troub les hooting Techn iques 4-4 Corrective Mainte nance SE CTION 8 DIAGRAMS AN D CI RCUIT BOAR D General 4-7 ILLUSTRATIONS Obtaining Replacement Parts 4-7 Soldering Techniques 4-7 Symbols and Reference Designators 8-1 Com ponent Replacement 4-10 Voltage and Waveform Test Cond itio n s 8-2 Recalibratio n After Repair 4-13 Diagrams Instrument Repackaging 4-13 Circu it Board Illustrations ι

CH ANG E INFORMATION ι ι ι ι ι ι ι ι ι ι ι ι ι ι ι CO NTENTS (con t) 453Α/R453A Mec han ical Parts List I nformation Abbreviations and symbols used in th is manu al are based on or Index of Mec hanical Parts List taken directly from IEEE Standard 260 "Standard Symbols for and Ill ustration s Units", MIL-STD-12B and ot her standard s of the electronics industry . Change information , if any, is located at the rear of Mec han ical Parts List th is manual .

453Α/R 453A Introduct i on switch set to Χ -Y) . The regulated DC power supplies main- The Tektronix 453Α Oscilloscope is α transistorized tain constant output over α wide variation of line voltages portable oscilloscope designed to operate in α wide range of and frequencies . Total power consum ption of the instru- environmental conditions . The light weight of the 453Α ment is approximately 90 watts . allows it to be easily transported, wh ile providing th e per- formance necessary for accurate h igh -frequency measu re ments . The dual-channel DC-to-60 MH z vertical system pro- Information given in th is instruction manual applies to vides cali brated d eflection factors from 5 millivolts to 10 the R453A also unless otherwise noted . T he R453A is volts/division . Channels 1 and 2 can be cascaded using an electrically identical to the 453Α , but is mec hanically external cable to provide α one millivolt minimum deflec- adapted for mounting in α standard 19-inc h rack . Rack - tion factor ( both VOLTS/DIV switch es set to 5 mV ) . Mounting in structions and α d imensional drawing for the R453A are provid ed in Section 6 of th is manual . The trigger circuits provide stable triggering over th e full range of vertical frequency response . Separate trigger con- trols are provided to select the desired triggeri ng for the Α and Β sweeps . One of th ree sweep modes can be selected T h is instrument will meet the electrical characteristics for the Α sweep; automatic, normal, or single sweep. The listed in Table 1-1 following com plete calibration as given horizontal sweep provides α maximum swee p rate of 0 .1 in Section 5 . The performance check procedure in Section microsecond/division (10 nanoseconds/d ivision usi ng 10Χ 5 provides α convenient method of check ing instrument magnifier) along with α delayed sweep feature for accurate performa nce without mak ing internal checks or ad just- relative-time measurements . Accurate Χ -Υ measurements ments . T he following electrical characteristics apply over α can be mad e with Channel 2 provid ing the vertical deflec- calibration interval of 1000 hours and an ambient temper- tion, and C hannel 1 provid ing the horizontal deflection ature range of 0°C to +50°C, except as otherwise ind icated . ( ΙΝΤ T R IG switch set to C H 1 O R Χ-Y, HOR IZ DISPLAY Warmu p time for given accuracy is 20 minutes . Deflection F actor Deflection Accuracy Variable Deflection Factor Ι Continuously variable between cali- Ι Extend s maximum deflection factor to brated settings . at least 25 volts/d ivision . TABLE 1-1 ELECT R ICAL Characteristic Performance Requirement Su pplemental Information VER TICA L DEFLECTIO N SYSTEM 5 millivolts/ division to 10 volts/divi- Selected by VO LTS/DIV switch . sion in 11 calibrated step s for each Ste ps in 1-2-5 sequence . ch annel . Less than one millivolt/divi- sion when Channel 1 and 2 are cas- cad ed. Wit h in 3% of indicated deflection . With GAI N correctly adjusted at 20 Cascaded deflectio n factor uncali- mV and VA R VO LTS/DI V control set brated . to calibrated .

without Ρ6061 Probe) 20 mV to 10 VOLTS/DIV Channels 1 and 2 cascaded AC Low-Frequency Response (lower -3 d B point) With Ρ6061 Probe In p ut RC Characteristics Resistance Maximum Safe Input Voltage Input Cou pling M odes Vertical Display M odes Chopped Repetition Rate Amp lifier Crosstalk Common Mode Rejection Ratio (all deflection factors) Polarity Inversion Signal Delay L ine DC to at least 60 megahertz DC to at least 50 megahertz DC to at least 40 megahertz DC to at least 25 megahertz 1 .6 hertz or less at all deflection factors . 0.16 hertz or less at all deflection factors . AC or DC . TABLE 1-1 (cont) Performance Requirement Channel 1 only . Channel 2 only . Dual-trace, alternate between channels . Dual-trace, chopped between channels. Added algebraically . Approximately 500 kilohertz . 100 :1 or greater, DC to 20 megahertz . At least 20 :1 DC to one kilohertz for signals less than eight times the VOLTS/DIV switch setting . Disp layed signal from Channel 2 can be inverted . Permits viewing of lead ing edge of triggering signal (internal triggering only) . Supplemental Information Driven from 25-ohm source . VAR VOLTS/DIV control set to calibrated position . In put Coupling switch set to AC . One megohm ±2% App roximately 20 picofarads 600 volts DC + peak AC (one kilohertz or less) . Selected by Input Coupling switch .

DC E xternal Trigger Sensitivity AC LF REJ HF REJ DC Characteristic TABLE 1-1 (cont) Performance Req uirement Supplemental Information TR IGGER I NG (Α AN D Β SWEEP) Internal from d isp layed channel or Selected by SO URC E switch . from C hannel 1 only . Internal from AC power source . External . External divide by 10 . AC AC low-frequency reject AC high-frequency re j ect DC Sweep can be triggered from positive- Selected by SLO PE switch going or negative-going portion of trigger signal . 0.3 d ivision of deflection, minimum, 30 hertz to 10 megahertz ; increasing to 1 .5 division at 60 megahertz . 0.3 d ivision of deflection, minimum, 30 kilohertz to 10 megahertz ; in- creasing to 1 .5 division at 60 mega- hertz . 0.3 d ivision of deflection, minimum, 30 hertz to 50 kilohertz . 0.3 d ivision of deflection, minimum, DC to 10 megahertz ; increasing to 1 .5 d ivision at 60 megahertz . 50 millivolts, minimum, 30 hertz to 10 SOUR CE switch set to EXT . Triggering megahertz ; increasing to 200 millivolts signal requ irements increase d 10 times at 60 megahertz . for ΕΧΤ - 10 position . 50 millivolts, minimum, 30 kilohertz to 10 megahertz ; increasing to 200 millivolts at 60 megahertz . 50 millivolts, minimum, 30 hertz to 50 kilo h ertz . 50 millivolts, minimum, DC to 10 mega h ertz ; increasing to 200 millivolts at 60 megah ertz . Specification-453Α/R453A Selected by CO UPL I N G switch .

Single Sweep (Α Sweep only) Display Jitter External Trigger Input R C Characteristics Characteristic LEVEL control range ΕΧΤ ΕΧΤ = 10 Maximum safe inpu t voltage Sweep Rates Α sweep (delaying sweep ) Β sweep (delayed sweep) Sweep Accuracy Over center eigh t d ivisions 5 s/DI V to 0.1 s/DI V 50 ms/DIV to 0.1 μ s/DI V Sweep Linearity Over any two division portion with- in cente r eight divisions (all sweep rates) TABLE 1-1 (cont) Performance R equirement Stab le d isp lay presented with signal amp litudes given under Internal and External Trigger Sensitivity above 20 hertz . Presents α free-ru nning sweep for lower freq uencies or in absence of trigger signal . Α Sweep Generator p roduces only one sweep when triggered . Further swee ps are locked out until RES ET bu tton is pressed . Trigger sensitivity same as given for internal and external sen- sitivity . One nanosecond or less at 10 nano- second s/d iv ision sweep rate ( MAG switch set to Χ 10) . HO R IZO NTAL D EFLECTIO N SYSTEM Α and Β Sweep Generator Performance Requi rement 0°C to +40°C Ι -150C to +55°C Unmagnified Ι Magnifie d I Unmagn ified I Magnifie d With in 3% Ι W ithin 4°/ο 1 W ithin 5°/ο Ι W ithin 6% With in 3% Ι With in 4% 1 W ithin 4% With in 5°/ο Ι W ith in 5°/ο Ι W ithin 5% Supplemental Information One megohm paralleled by 20 picofara ds (approximate) . At least + and - 2 volts . At least + and - 20 volts . 600 volts DC + peak AC (one k ilohertz or less) 0 .1 microsecond/d ivision to 5 seconds/ Ι Selected by Α ΤΙΜΕ/DI V switch. Steps in d ivision in 24 calibrated steps. 1-2-5 sequence . 0 .1 microsecond/d ivision to 0.5 sec- Ι Selected by Β ΤΙΜΕ/DI V switch . Step s in and/d ivision in 21 calibrated ste ps 1-2-5 sequence . W ithin 5% W ithin 10% Ο

Α Sweep Length M ixed Sweep Accu racy Calibrated Delay R ange Delay Accuracy Over Center E ight Divisions 5sto0 .1 s/DI V 50 ms to 1 μs/DIV Incremental Mu ltiplier L inearity Delay Time J itter Accuracy R esistance Capacitance Characteristic Inpu t to CH 1 or Χ connector Deflection F actor Χ B andwidth at Upper -3 d B Point Input R C Characteristics Phase difference between Χ and Υ amplifiers TABLE 1-1 (cont) Specificatio n-453Α/R453A Performance Requirement I Supplemental Information Continuously variab le between cali- E xtends maxim u m Α sweep rate to at brated sweep rates . least 12.5 seconds/d ivision and Β sweep ~ rate to at least 1 .25 seconds/division . Variable from four divisions or less Ι Measured at 1 ms/DIV. to 10 divisions or greater . Mixed and Delayed Sweep W ith in 2°/ο ± measured Α sweep error Exclud e first 0.5 division of displayed when viewing th e Α portion only . Β sweep and 0.2 d ivision or 0.1 micro- portion accuracy is same as stated second, wh ichever is greater, after tran- u nder Sweep Accuracy . isition from Α to Β sweep. Continuous from 50 seconds to 0.2 Selected by DELAY-TIME MULTI PL I E R microsecon ds . ( d ial and Α ΤΙΜΕ/DIV switch . 0°C to +40° C Ι -15 0C to +55° C W ith in 1 .5% of in- W ithin 3.5% of in- d icated delay Ι d icated delay W ithin 1 .5%ο of in- W ithin 2°/ο of in- d icated delay d icated delay W ithin 0.2% Ι W ithin 0.3% Less th an 1 part in 20,000 of the maximum availab le delay time (10 times Α ΤΙΜΕ/DI V switch setting) . External Horizontal Amplifier 5 millivolts/division to 10 volts/ ΙΙΝΤ TR IG switch set to CH 1 O R Χ-Y . division in 11 cali brated steps . Steps in 1-2-5 sequence . 0° C to +40 °C -15 °C to +55°C External horizontal gain correctly ad- With in 5°/ο of in- Within 8°/ο of in- Dusted at 20 mV. d icated deflection d icated deflection F ive megahertz or greater 3° or less at 50 k ilohertz 1 megohm ±2°/ο Approximately 20 picofara ds

I NPUT Connector Deflection Factor Χ Bandwidth at Upper -3 d B point Input RC Characteristics Phase difference between Χ and Υ amp lifiers Maximu m Safe Input Voltage Waveshape Polarity Outpu t Voltage Outpu t Current Repetition Rate Ι One kilohertz . Accu racy Voltage Cu rrent Repetition Rate Risetime Outpu t Resistance Characteristic TABLE 1-1 (cont) Performance R equ irement Β SOUR CE switch in ΕΧΤ ; 270 milli- volts/d ivision ±15% . Β SO UR C E switch in ΕΧΤ - 10; 2.7 volts/d ivision ±20% . F ive megahertz or greater 3 ° or less at 50 kilohertz Squ are wave Positive going . CAL IBRATOR 0 .1 volt or 1 volt, peak to peak Five milliamperes throu gh PROBE LOOP on side panel 0°C to +40°C -150C to +55 °C ±1% ±1 .5% ±0.5% Ι ±1°/α One microsecond or less Supplemental Information One megohm parallele d by 20 picofarads (approximate) 600 volts DC + peak AC (one kilohertz or less) . Baseline at zero volts . Selected by CAL I BR ATO R switch . Approximately 200 ohms in 1 V position Approximately 20 ohms in 0 .1 V position

I nput Resistance at DC Input Co u pling Maximum Inpu t Voltage Α and Β Gate Waveshape Amplit ude Polarity Duration Outpu t Resistance Characteristic Vertical Signal Out (CH 1 only) Outpu t V oltage Bandwidth Outpu t coupling Output resistance TABLE 1-1 (cont) Performance Requirement Su pplemental Information Ζ AXIS I NPU T Five volt peak-to-peak signal produces noticeable modulation at normal intensity . Positive-going input signal decreases trace intensity ; negative-going input signal increases trace intensity . DC to 50 megahertz or greater . DC cou pled Rectangular pulse Positive-going OUT PUT SIG NALS Approximately 12 volts peak Same duration as respective sweep. 25 millivolts or greater, for each divi- Into one megoh m load. ΙΝΤ T R IG switch sion of CRT display . I set to NO RM . DC to 25 mega hertz or greater when cascaded with Channel 2, or into 50- oh m load . DC coup led Approximately 47 kilohms 200 volts DC + peak AC Specification-453Α/R453A Baseline at about -0.7 volt A pproximately 1 .5 kilohms . Approximately 50 ohms .

Line F requency 230-volts nominal Characteristic Voltage Ranges (AC, RMS) 115-volts nominal Maximum Power Consumption Internal TABLE 1-1 (cont) Performance Requirement Supplemental Information DISPLAY E ight divisions vertical by 10 divisions horizontal . Each d ivision equals 0 .8 centimeter . Variable edge ligh ti ng . Ρ31 standard . Others available on special order . L imits display within graticule area when pressed. 115 volts nominal or 230 volts nominal . I N ominal line voltage and voltage range selected by L ine Voltage Selector . Given voltages apply wh en line voltage contains 2°/ο or less harmonic d istortion . 90 to 110 volts 104 to 126 volts 112 to 136 volts 180 to 220 volts 208 to 252 volts 224 to 272 volts POWER SUPPLY 48 to 62 hertz 92 watts, one ampere at 60 hertz, 115- volt line

Characteristic I Performance NO ΤΕ Condu cted in This instrument will meet the electrical characteristics terference given in Table 1-1 over the following environmental limits. Complete details on environmental test pro- cedures, including failure criteria, etc ., can be ob- tained from Tektronix, Inc . Contact your local Tektronix Field Office or representative . Transportation Temperature Operating Storage Altitude Operating Storage Humidity Operating and storage Vibration Operating and non-operating Shock O perating and non-operating E lectro-magnetic Interference (EMI) as tested in Μ Ι L- Ι - 6181D (when equ ipped with M OD 163D only) Radiated inter- ference -150C to +550C -550C to +75°C 15,000 feet maximum . Maximum operati ng tem perature decreases by 1 °C per 1000 feet increase in amplitude above 5000 feet . Tested to 50,000 feet F ive cycles (120 h ou rs) to 95% rela- tive humidity referenced to MIL- E-16400F . 15 minutes along each of the th ree major axes at α total displacement of 0.025-i nch peak to peak (4 g at 55 Hz) with frequency varied from 10-55-10 Hz in one-min ute cycles . H ol d at 55 H z for th ree minutes on each axis . Two shocks at 30 g, one-half sine, 11 millisecond duration each direc- tion along eac h ma j or axis . Gu illotine-type shocks . Total of 12 sh ocks . Interference rad iated from the in - strument under test with in the Cooling F in ish Characteristic Overall Dimensions, 453Α (measured at maxim u m points) Height Width Length Overall Dimensions, R453A (measu red at maximum points) Height Width Length Specification-453 Α/R453A Performa nce given limits from 150 k ilohertz to 1000 megah ertz (mesh filter instal- led ) . Interference conducted out of the instru ment u nder test th rough th e power cord within th e given limits from 150 kilohertz to 25 mega- hertz . M eets N ational Safe Transit type of test when packaged as shipped from Tektronix, Inc . TABLE 1-3 PH YSICAL Information Safe operating temperatu re main- tained b y forced-air cooling . Automatic resetting thermal cutout p rotects instrument from over- heating . Anod ize d aluminum panel and chassis . Blue vinyl-coated cabinet . 7.2 inches (18 .3 centimeters) 12.6 inches (32 .0 centimeters) 20.7 inches (52 .6 centimeters) in- cluding front cover ; 22.4 inches (56 .9 centimeters) with h and le positioned for carrying . 7 .0 inches (17 .8 centimeters) 19 inches (48.3 centimeters) 17.4 inches (44.2 centimeters) be- h ind front panel ; 19 .2 inches (48.8 centimeters) overall .

out accessories) R453A (without accessories) Characteristic Information STANDARD ACCESSORIES Approximately 30 pounds (13.6 Standard accessories sup plied with the 453Α and R453A kilograms) . are listed in the Mechanical Parts L ist illustrations . F or App roximately 33.5 pounds (15 .2 optional accessories available for use with this instrument, kilograms) . see the current Tektronix, Inc . catalog .

ι ι t ι ι ι General To effectively u se the 453Α , the operation and capabil- ities of the instrument must be known . This section de- scribes the operation of the front-, side-, and rear-panel controls and connectors, gives first time and general oper- ating information, and lists some basic applications for this instrument . Front Cover The front cover furnished with the 453Α provides α dust-tight seal around the front panel . Use the cover to protect the front panel when stori ng or transporting the instrument . The cover also provides storage space for probes and other accessories (see F ig . 2-1) . Operating Voltage CAUTION This instrument is designed for operation from α power source with its neutral at or near earth (ground) potential with α separate safety-earth con- ductor. It is not intended for operation from two phases of α multi-phase system, or across the legs ofα single-phase, three-wire system. The 453Α can be operated from either α 115-volt or α 230-volt nominal line-voltage source . The Line Voltage Selector assembly on the rear panel converts the instrument from one operating range to the other . In addition, this assembly changes the primary connections of the p ower transformer to allow selection of one of three regulating ranges . The assembly also inclu des the two line fuses . When the instrument is converted from 115-volt to 230-volt nominal operation, or vice versa, the assembly connects or disconnects one of the fuses to provide the correct protec- tion for the instrument . Use the following procedure to convert this instrument between nominal line voltages or regulating ranges . ι Fig . 2-1 . Accessory storage provided in front cover . NOΤΕ Line Black Neutral White Safety earth (ground) Green 453Α/R453A 3 . To convert from 115-volts nominal to 230-volts nominal line voltage, pull out the Voltage Selector switch bar (see Fig . 2-2) ; turn it around 180 ° and plug it back into the remaining holes . Change the line-cord power plug to match the power-source receptacle or use α 115- to 230-volt adapter . Color-coding of the cord conductors is as follows (in accordance with National Electrical Code) : 1 . Disconnect the instrument from the power source . 4 . To change regulating ranges, pull out the Range Selec- tor switch bar (see F ig . 2-2) ; slide it to the desired position 2 . Loosen the two captive screws which hold the cover and p lug it back in . Select α range which is centered about onto the voltage selector assembly ; then pull to remove the the average line voltage to which the instrument is to be cover . connected (see Table 2-1) .

wit h cover removed ) . TABLE 2-1 Regulating Ranges Regu lating Range Range Selector 115-Volts 230-Volts Switch Position N ominal N ominal The feet on the rear panel provide α convenient cord wra p to store the power cord w hen not in use . Operating Temperature Th e 453Α is cooled by air drawn in at th e rear and blown out throug h holes in the top and bottom covers . Adequate clearance on the to p, bottom, and rear must be p rovided to allow h eat to be d issipated away from th e instru ment . The clearance p rovided by the feet at th e bottom and rear sh ould be maintained . If possible, allow about one inch of clearance on the top. Do not block or restrict the air flow from the air-escape holes in the cabinet. Α th ermal cutout in th is instrument provides thermal protection and disconnects the power to the instrument if the internal temperature exceeds α safe operating level . Power is automatically restored when the temperature returns to α safe level . Operation of th e instrument for extended periods without the covers may cause it to over- heat and the thermal cutout to open . The air filter shoul d be cleaned occasionally to allow the maximum amount of cooling air to enter the instrument . Cleaning instructions are given in Section 4 . Rackmounting ι connect th is instrument to α two-wire AC power system, be , sure to connect the ground lead of the adapter to earth (ground) . F ailure to com plete the ground system may allow the ch assis of th is instrument to be elevated above ground potential and p ose α sh ock hazard . ι ι ι ι ι ι ι LO (switc h bar in 90 to 110 volts 180 to 220 volts left holes) Μ (switch bar in 104 to 126 volts 208 to 252 volts Th e 453Α can be operated where the ambient air midd le holes) tem peratu re is between -15°C and +55°C . Derate the max- ΗΙ (switch bar in 112 to 136 volts 224 to 272 volts imu m operating temperature 1'C for each add itional 1000 righ t holes) feet of altitude above 5000 feet . Th is instrument can be stored in ambient temperatu res between -55 °C and +75°C . After storage at tem perat u res beyond the operating 5 . Re-install th e cover and tighten the two captive limits, allow the chassis tem perature to come within th e screws . operating limits before power is app lied . 6 . Before ap plying power to the instrument, check that the ind icating tabs on the switch bars are protru ding Operating Posit i on through the correct h oles for the desired nominal line volt- The handle of the 453Α can be positioned for carrying age and regu lating range . or as α tilt-stand for the instrument . To position the handle, press in at both pivot points (see rig . 2-3) and turn the handle to the desired position . Several positions are pro- vided for convenient carrying or viewing . The instrument may also be set on the rear-panel feet for operation or This instrument may be damaged if operated with the storage . L ine Voltage Selector assembly set to incorrect positions for the line voltage applied, The 453Α is designed to be used with α three-wire - AC Complete information for mounting the R453A in α power system . If α three- to two-wire adapter is used to cabinet rack is given in Section 6 of th is manual . 2-2

Fig . 2-3 . Handle positioned to provide α stand for the instrument . CONTRO LS AND CONNECTO RS CH 1 O R Χ and In put connector for vertical signal . General CH 2 O R Υ Α brief descri p tion of the function or operation of the front-, side-, and rear-panel controls and connectors follows (see F ig . 2-4) . M ore detailed information is given in th is section under General Operating Information . Disp lay I NTENSITY Controls b rightness of disp lay . A LT : Dual trace d isplay of signal on bot h c h annels . Display switched between channels at end of each sweep . SCALE I LLUM Controls graticu le illumination . CHOP : D u al trace display of signal BEAM FI N D ER Com presses disp lay with in graticu le on both ch annels . Display area independent of display posi- switched between channels at α tion or app lied signals . repetition rate of about 500 kilohertz . Vertical (both channels except as noted ) Provid es adjustment for α well- defined d isp lay . Operating Instructions-453Α/R453A POSITIO N Controlsvertical position of trace. GAIN Screwdriver adj ustment to set gain of the Vertical Preamp . Input Cou pling Selects m ethod of coupling input (AC GN D DC) signal to V ertical Deflection System . AC : DC component of input signal is blocked . Low frequency limit (-3 dB point) is abou t 1 .6 hertz . GN D : Input circu it is grounded (does not ground applied signal) . DC : All components of the input signal are passed to the Vertical Deflection System . STEP ΑΤΤΕΝ BAL Screwd river adjustment to balance Vertical Deflection System in th e 5, 10, and 20 mV positions of the VO LTS/DI V switch . MOD E Selects vertical mode of operation . CH 1 : The Channel 1 signal is d is- played . CH 2 : The Channel 2 signal is d is- played . ADD : Channel 1 and 2 signals are VO LTS/DI V Selects vertical deflection factor algebraically added and th e alge- (VAR control must be in calibrated braic sum is disp layed on the position for indicated deflection C RT . factor) . ΙΝΤ Τ R ΙG Selects source of internal trigger sig- VA R Provides continuou sly variable de- ηαΙ from vertical system . Also re- flection factor between the cali- lects sou rce of Χ signal for Χ -Υ brated settings of th e VOLTS/DI V mode operation . switch. NO RM : Sweep circuits triggered UN CAL Light indicates that the VA R con- from disp layed channel(s) . C h an- trol in not in the calibrated nel 1 signal available at C H 1 position . O UT connector . ι 2-3

CRT External Horizontal Channel l Channel 2 Α Triggering Α. Front panel Β. Side panel C. Rear panel F ig . 2-4. F ront-, side-, and rear-panel controls and connectors .

Inverts the Channel 2 signal when only) pulled out. Groun d (not labeled ) Binding post to estab lis h common ground between the 453A and any associated equipment . Α and Β Triggering (both where applicable) ΕΧΤ T R IG I NPUT 'Input connector for external trigger signal . Connector for Β Triggering also serves as external horizontal in put for the Χ signal when HO R IZ DISPLAY switch is in Χ -Υ position and Β SOUR CE switch is in ΕΧΤ position . SO UR C E Selects source of trigger signal . Ι NT : Internal trigger signal ob- tained from Vertical Deflection System . When CH 1 light is on, trigger signal is obtained only from the Channel 1 in pu t signal ; when the light is off, the trigger signal is obtained from the dis- p layed channel(s) . Source of internal trigger signal is selected by the ΙΝΤ TR IG switch . Α and Β Sweep Operating Instructions-453Α/R453A CH 1 OR Χ-Y : Sweep circuits trig- the signal connected to the CH 1 gered only from signal app lied to OR Χ connector (see ΙΝΤ TR IG the Channel 1 input connector . switch ) . No signal available at CH 1 OUT connector . CH 1 ligh ts, located CO UPL ING Determines method of coupling beside Α an d Β SO URCE trigger signal to trigger circu it . switches indicate when th e ΙΝΤ TR IG switch is in the C H 1 OR AC : Re jects DC and attenuates sig- Χ -Υ position . For Χ -Υ mode nals below about 30 hertz . Ac- operation, Channel 1 signal is cepts signals between about 30 connected to the H orizontal h ertz and 60 mega h ertz, Am plifier . LF REJ : Re jects DC and attenuates signals below about 30 kilohertz . Accepts signals between about 30 kilohertz an d 60 megahertz . HF REJ : Acce pts signals between about 30 hertz an d 50 kilohertz ; rejects DC and attenuates signals outside the above range . DC : Accepts all trigger signals from DC to 60 megahertz or greater . S LOPE Selects portion of trigger signal which starts the sweep . + : Sweep can be triggered from positive-going portion of trigger signal . - : Sweep can be triggered from negative-going portion of trigger signal . LEVEL Selects am plitude point on trigger signal at wh ich sweep is triggered . HF STAB Decreases d isplay jitter for high (A Triggering only) frequency signals . H as negligib le effect at low sweep rates . L I NE : Trigger signal obtained from DELAY-TIME Provides variable sweep delay be- α samp le of the line voltage MULTI PL I ER tween 0.20 and 10.20 times the de app lied to th is instru ment . lay time ind icated by the Α TIME/ DI V switch . ΕΧΤ : Trigger signal obtained from an external signal applied to the Α SWEEP TR IG'D L ight indicates that Α sweep is trig ΕΧΤ T R IG I NPUT connector . gered and will p roduce α stable dis- play with correct I NT ENSITY and ΕΧΤ - 10 : Attenuates external trig- POSITION control settings . ger signal approximately 10 times . UNCA L Α O R Β L ight indicates that either the Α VA R or Β ΤΙΜΕ/DI V VA R IA BLE CH 1 Light indicates that the internal control is not in the calibrated posi- trigger signal is obtai ned only from tion . 2-5

Α AND Β ΤΙΜΕ/DIV Α ΤΙΜΕ/DI V switch (clear plastic determined by the setting of the ' AND DELAY flange) selects the sweep rate of the DELAY TIME (Α ΤΙΜΕ/DI V ) TIME Α sweep circuit for Α sweep only switch and the DELAY-TIME operation and selects the basic de- MULTI PL I ER d ial . Sweep mode lay time (to be mu ltiplied by determined by Β SWEEP MOD E DELAY-TIME MULTI PL I ER dial switch. setting) for mixed or delayed sweep o p eration . Β ΤΙΜΕ/DIV (D E - M IXED : Both time bases are oper- ' LAY E D SWEEP) switch selects ating. The sweep rate of the first sweep rate of the Β sweep circu it part of the sweep is determined for mixed or d elayed sweep oper- by the Α ΤΙΜΕ/DIV switch ; the ation only . Variable controls must last part is determined by the Β ' be in calibrated positions for cali- ΤΙΜΕ/DIV switch . The amount brated sweep rates. of d isplay allocated to each time base is determined by th e setting Α VAR Provides continuously variable Α of the DELAY-TIME MULTI- sweep rate between calibrated set- PL I ER dial . tings of the Α ΤΙΜΕ/DIV switch. Α sweep rate is calibrated when con- Χ-Y : Horizontal deflection p ro- trol is set fully clockwise to cali- vided by an external signal . brated position . MAG Increases sweep rate to ten times ' Β SWEEP MOD E Selects Β sweep operation mode. setting of Α or Β ΤΙΜΕ/DIV switch by horizontally expand ing the cen TRIGGERABLE AFTER D ELAY ter division of the d isplay. Ligh t TIME : Β sweep circu it will not ind icates wh en magnifier is on, produce α sweep until α trigger pulse is received following the Α SWEEP MOD E Determin es the operating mode for delay time selected by the D E- Α sweep . LAY TIME (A TIME/DIV) switch and the DELAY-TIME AUTO TR IG : Sweep initiated by MULTI PL I ER d ial. the applied trigger signal at point selected by the Α LEVEL con- Β STARTS AFTER DELAY TIME : trol when th e trigger signal repe- Β sweep circuit ru ns immedi- tition rate is above about 20 ately following delay time selec- hertz and within the frequency ted by th e DELAY TIME switch range selected by the Α COUP- an d DELAY-TIME MULTI- LI NG switch. Triggered sweep PL I ER d ial. can be obtained only over the amplitude range of the applied HOR IZ DISPLAY Selects h orizontal mode of opera- signal . When th e Α LEVEL εοη- tion . trol is outside the amplitude range, the trigger repetition rate Α: Horizontal deflection provided is below the lower frequ ency by Α sweep. Β sweep inopera- limit (or above u pper limit for tive . HF REJ), or th e trigger signal is inadequate, the sweep free runs Α ΙΝΤΕΝ DUR I NG Β : Sweep rate at the sweep rate selected by the ' determined by Α ΤΙΜΕ/DIV Α ΤΙΜΕ/DI V switch to produce switch. An intensified portion α bright reference trace. appears on the disp lay d uring the Β sweep time . This position NORM T R IG : Sweep initiated by provides α chec k of th e duration the applied trigger signal at point an d position of the delayed selected by Α LEVEL control sweep ( Β ) with respect to the de- over the frequency range selec- laying sweep (Α) . te d by the Α COUPL I NG switch. Triggered sweep can be obtained Β (D ELAYED SWEEP) : Sweep rate only over the amplitude range of d etermined by Β ΤΙΜΕ/DIV th e applied trigger signal . Wh en , switch after the delay time the Α LEVEL control is outside

to obtain α well-defined d isplay. repetition rate is outside the fre- Does not require re-adj ustment in quency range selected by the Α normal u se . CO UPL I NG switch , or the trig- ger signal is inadequate, there is Β ΤΙΜΕ/DI V - Provid es continuously variable Β no trace . VAR IABLE sweep rate between calibrated set- tings of Β ΤΙΜΕ/DI V switch . Β SI N G LE SWEEP : After α sweep is sweep rate is calibrated when con- displayed, furth er sweeps cannot trol is set fully clockwise to CAL . be presented u ntil the RES ET button is pressed . Display is trig- PR O BE LOOP Current loop provid ing five-milliam- gered as for NO RM operation pere square-wave current from cali- using the Α Triggering controls . brator circuit . RES ET When th e RES ET button is p ressed Α GATE Output connector provid ing α rec- (SI NG LE SWEEP mode), α single tangular pulse coincident with Α d isplay will be presented (with cor- sweep. rect triggering) wh en the next trig- ger pu lse is received . RES ET light Β GATE Ou tput connector providing α rec- (insid e RES ET bu tton) remains on tangular pulse coincident with Β until α trigger is received and the sweep. sweep is com pleted . RESET button must be pressed before anot h er CH 1 OU T Outp u t connector p roviding α sweep can be presented. sam ple of the signal applied to the CH 1 OR Χ connector when the Α SWEEP LENGTH Adjusts length of Α sweep. In the ΙΝΤ T R IG switch is in the N O RM FULL position (clockwise detent), position . the sweep is at least 10 divisions long . As the control is rotated CAL I BRATOR Switch selects output voltage of counterclockwise, the length of Α Calibrator . 1-volt or 0.1-volt square sweep is reduced until it is less than wave available . four divisions long ju st before the detent in the fu lly-counterclock - T R ACE ROTATION Screwd river adju stment to align wise position is reached . In the Β trace with horizontal graticule lines . EN DS Α position (counterclock - wise detent), the Α sweep is reset at Rear Panel the end of the Β sweep to provide the fastest possible sweep repetition Ζ AXIS I NPUT Input con nector for intensity mod- rate for delayed sweep disp lays . u lation of th e CRT d isplay . POSITIO N Controls horizontal position of Line Voltage Selector Switch ing assem bly to select the trace. nominal operating voltage and the line voltage range . The assembly F I NE Provides more precise horizontal also inclu des the line fuses . position adju stment. Voltage Selector : Selects nominal 1 kH z Calibrator ou tput connector . operating voltage range (115 V or 230 V) . POWER ON L ig h t : In d icates that POWER switch is on and the instrument Range Selector : Selects line voltage is connected to α line voltage range (low, med ium, high ) . source . Switch : Controls power to the instrument. FIRST-TIME O PER ATIO N Side Panel The following steps will demonstrate the use of the con- trols and connectors of the 453Α . It is recommended that ASTIG Screwdriver adju stment used in con- th is procedure be followed com pletely for familiarization ju nction with the FOC US control with th is instrument . 2-7

Display 2-8 1 . Set the controls as follows: 4 . Advance the I NTENSITY control u ntil th e trace is at the desired viewing level (near mid range) . Display Controls INTENSITY Counterclockwise F OCU S Midrange SCALE ILLUM Counterclockwise 5. Connect the 1 kH z CAL connector to the CH 1 OR Χ connector with α BN C cable. ι ι ι ι 6. Turn the Α LEVEL control toward 0 u ntil th e display Vertical Controls ( both channels if applicable) becomes stable . N ote that the Α SWEEP T R IG'D light is on VOLTS/DIV 20mV wh en the d isplay is stable . VAR Calibrated POSITIO N M id range Input Coupling DC 7 . Adj ust the FOCUS control for α sharp, well-defined MODE CH 1 disp lay over the entire trace length. (If focused d isp lay can- ΙΝΤ TR IG NORM not be obtained, see Astigmatism Ad justment in th is I NVER T Pushed in section .) Triggering Controls (both Α and Β if applicable) 8. Disconnect the in put signal and move the trace with LEVEL Clockwise (+) the Channel 1 POSITION control so it coincides with one SLOPE + of the h orizontal graticule lines. If the trace is not parallel CO UPLI NG AC with the graticule line, see Trace Alignment Adjustment in th is section. SOURCE ΙΝΤ Sweep Controls 9. Rotate the SCALE I LLUM control through out its range and notice that the graticule lines are ill uminated as ' DELAY-TIME 0.20 the control is turned clockwise (most obvious with mesh or MULTI PL I ER tinted filter installed) . Set control so graticule lines are Α and Β ΤΙΜΕ/DIV .5 ms illu minated as desired . Α VAR Calibrated Β SWEEP MODE Β STA RTS AFTER DELAY TIME Vertical H OR IZ DISPLAY Α MAG OFF 10 . Change the CH 1 V OLTS/DIV switch from 20 mV , POSITION Midrange to 5 mV . If the vertical position of the trace sh ifts, see Step Α SWEEP LENGT H FULL Attenuator Balance in th is section. Α SWEEP MODE AUTO TR IG POWER OFF 11 . Set the CH 1 VOLTS/DIV switch to 20 mV and set the Channel 1 Input Cou pling switch to AC . Connect the 1 Side Panel Controls kHz CA L connector to both the CH 1 OR Χ and CH 2 OR Υ connectors with two BNC cables and α BNC Τ connector. Β ΤΙΜΕ/DIV CAL VAR IABLE CA L I BR ATOR .1 V NOTE If the BNC cables andBNC Τ connecto r are not avail- 2 . Connect the 453Α to α power source th at meets the able, make the following changes in the procedure. voltage and frequency requirements of the instrument. If Place the BNC jack post (supplied accessory) on the 1 , th e available line voltage is outside the limits of the Line kHz CA L connector and connect the two 10Χprobes Voltage Selector assembly (on rear panel), see Operating (supplied accessories) to the CH 1 and CH 2 connec- Voltage in th is section . tors. Connect the probe tips to the BNC jack post. ' Set the CALIBRATOR switch (on side-panel) to 1 V. 3. Set the POWER switch to ON . Allow about five min- utes warmup so th e instrument reaches α normal o perating 12 . Turn the Channel 1 POSITION control to center the ' temperature before proceed ing. d isplay. The d isplay is α square wave, five d ivisions in amp li-

22 . Set the MOD E switch to ADD . The d isp lay shou ld display is not five divisions in am plitude, see Vertical Gain be four divisions in am plitude . N ote th at either POSITIO N Adjustment in th is section . control moves the disp lay . 13 . Set the Ch annel 1 Input Cou pling switch to G N D 23 . Pull th e I NVERT switch . The disp lay is α straight and position th e trace to th e center horizontal line with the line indicating that the algebraic su m of the two sign als is Channel 1 POSITIO N control . Th is provides α ground refer- zero (if th e C hannel 1 and 2 gain is correct) . ence at th e center horizontal line . 24 . Set either VO LTS/DI V switch to 20 m V . The 14 . Set th e Channel 1 Input Cou pling switch to DC . square-wave display indicates that the algebraic sum of the Note that th e baseline of the waveform remains at the cen- two signals is no longer zero . Return the MOD E switch to ter horizontal line (ground reference) . C H 1 and both VO LTS/ΠΙ V switches to .2 (if using 10Χ probes, set both VO LTS/DI V switches to 20 mV) . Push in the I NVERT switch. 15 . Set th e Channel 1 Input Coup ling switch to AC . Note that th e waveform is centered about the center h ori zontal line (ground reference) . Triggering 25 . Set the CA L I BR ATOR switch to 1 V . Rotate the Α LEVEL control th rough ou t its range . The d isp lay free runs 16 . Tu rn th e Channel 1 VA R control th roughout its at the extremes of rotation . N ote th at the Α SWEEP range . N ote th at the UN CA L light comes on when the VA R T R IG'D ligh t is on only wh en the d isplay is triggered. control is moved from th e cali brated position (fu lly clock- wise) . The deflection sh oul d be reduced to about two d ivi- sions. Return the VA R control to th e calibrated position . 26 . Set the Α SWEEP MOD E switch to NO RM T R IG . Again rotate th e Α LEVEL control throughou t its range . Α d isp lay is presented only when correctly triggered . T he Α 17 . Set th e MOD E switch to CH 2 . SWEEP TR IG'D ligh t operates as in A UTO TR IG . Retu rn th e Α SWEEP MOD E switch to AUTO T R IG and set the Α LEVEL control for α stable display . 18 . Tu rn the Channel 2 POSITIO N control to center th e display . The d isp lay will be similar to the previous display for Channel 1 . Chec k Channel 2 step attenuator balance 27 . Set th e Α SLO PE switch to - . The trace starts on and gain as described in steps 10 th rough 12 . The Channel 2 the negative part of the sq uare wave . Return the switch to Input Cou pling switch and VAR control operate as de- + ; the trace starts with the positive part of the squ are wave. scribed in steps 13 th rough 16 . 28 . Set th e Α CO UPL I N G switch to DC . Turn th e Ch an 19 . Set both VOLTS/DIV switches to 50 mV. nel 1 POSITIO N control u ntil the d isplay becomes u nstable (only part of square wave visible) . Return the Α COUP- LING switch to AC ; the disp lay is again stable . Since chang- 20 . Set the MOD E switch to A LT and position the Chan- ing trace position ch anges DC level, th is shows how DC nel 1 waveform to the top of the graticule area and the level changes affect DC trigger coupling . Return the d isp lay Channel 2 waveform to the bottom of the graticule area . to the center of the screen . Turn the Α ΤΙΜΕ /DIV switch through out its range . N ote that the d isplay alternates between ch annels at all sweep rates . 29 . Set the MOD E switch to CH 2 ; the display shou ld be stable . Remove th e signal connected to Channel 1 ; th e dis- play free runs . Set th e ΙΝΤ TR IG switch to NO RM ; th e 21 . Set the MODE switch to CHOP and the Α TIME/ display is again stable . Note that the CH 1 ligh ts in Α and Β DI V switch to 10 μ s . N ote the switch ing between ch annels Triggering go out wh en the ΙΝΤ TR IG switch is ch anged to as shown by th e segmented trace . Set the ΙΝΤ T R IG switch NO RM . to CH 1 O R Χ-Y ; the trace sh ould appear more solid , since it is no longer triggered on th e between-ch annel switch ing transients . Tu rn the Α ΤΙΜΕ/DI V switch th roughout its 30. Set the Α SOURC E switch to L I NE . Connect α 10Χ range . Α dual-trace d isp lay is presented at all sweep rates, probe (supp lied accessory) to the CH 2 O R Υ connector . but unli ke A LT, both channels are disp layed on each trace Connect the probe tip to α line-voltage sou rce and set the on α time-sh aring basis . Return the Α ΤΙΜΕ/DI V switch to CH 2 VO LTS/DI V switch for α disp lay abou t four d ivisions .5 ms . in amplitude . If necessary, adju st the Α LEVEL control for Operating Instructions-453 Α /R453A 2-9

α stable d isp lay of the sine-wave . Notice th at the display intensified portion appears to jum p between positive slopes starts on the correct slope . Disconnect th e probe . of the d isp lay . Set the Β S LOPE switch to - ; the intensified portion begins on the negative slope . Rotate the Β LEVEL control ; th e intensified portion of the display disappears 31 . Connect th e Calibrator signal to both th e CH 2 O R w hen th e Β LEVEL control is out of the triggerable range . Υ and Α ΕΧΤ T R IG I NPUT connectors. Set the Α Return th e Β LEVEL control to 0 . SOURCE switch to EXT . Operatio n of the LEVEL, S LOPE, and COUPLI NG controls for external triggering are the same as described in steps 25 throu gh 28 . 39 . Set the HO R IZ DISPLAY switch to Β (DELAY E D SWEEP) . Rotate the D ELAY-TIME MULTI PL I ER d ial throughout its range ; about one-half cycle of the waveform 32 . Set the Α SOURC E switch to ΕΧΤ - 10 . O peration shou ld be displayed on the screen (lead ing edge visible only is th e same as for EXT . N ote that the Α LEVEL control has at h igh INT ENSITY control setting) . The disp lay remains less range in this position, ind icating trigger signal attenu- stable on th e screen, indicating that the Β sweep is trig- ation . Return the Α SOUR CE switch to INT . gered. 33 . Operation of the Β Triggering controls is similar to Α 40 . Set the Β SWEEP MOD E switch to Β STA RTS Triggering . AFTER DELAY TIME . Rotate the DELAY-TIME MULTI- PL I ER d ial th rough out its range ; the display moves contin- uou sly across the screen as the cont rol is rotated. Normal and Magnified Sweep 34 . Set the Α ΤΙΜΕ/DI V switch to 5 ms and the MAG 41 . Rotate the DELAY-TIME MULTI PL I ER d ial fu lly switch to Χ 10 . The d isp lay should be similar to that ob- counterclockwise a nd set the HO R IZ DISPLAY switch to Α tained with the Α ΤΙΜΕ/DI V switch set to .5 ms and the ΙΝΤΕΝ D UR I NG Β . Rotate the Α SWEEP LENGTH εοη MAG switch to OFF . trol counterclockwise ; the length of the d isp lay decreases . Set the control to the Β EN DS Α position ; now the disp lay end s after the intensified portion . Rotate the DELAY- 35 . Turn the horizontal POSITION control throughout TIME MULTI PL I ER d ial and note that the sweep length its range ; it shou ld be possible to position the display across increases as the d isp lay moves across th e screen . Return the the complete graticule area . Now turn th e F I NE control . Α SWEEP LENGTH control to FULL . The d isplay moves α smaller amount and allows more pre- cise positioning . Retu rn the Α ΤΙΜΕ/DI V switch to .5 ms, the MAG switch to O FF and return the start of the trace to 42 . Turn the Β VA R IABLE control (on side panel) the left graticule line . th roughout its range . N otice that the UNCA L Α OR Β light comes on when the Β VAR IABLE control is moved from the CAL position (fu lly clockwise) . The Β sweep rate 36 . Turn the Α VAR control throughout its range . (intensified portion) is slower by about 2.5 times in the N otice that the UN CAL Α OR Β light comes on wh en the Α fully counterclockwise position, as indicated by α longer VAR control is moved from the cali brated position (fu lly intensified zone . Return the Β VA R IABLE control to CAL. clockwise) . The sweep rate is slower by about 2.5 times i n the fully countercloc kwise position as ind icate d by more cycles d isplayed on the CRT . Retu rn the Α VA R control to 43 . Set the HOR IZ DISPLAY switch to M IX E D and the the calibrated position . DELAY-TI ME MULTI PL I ER to 5.00 . N otice th at the first half of th e sweep is at the sweep rate of the Α time base (5 ms/DI V), and the last half is at th e sweep rate of th e Β time Delayed Sweep base (0.5 ms/DI V) . Rotate the DELAY-TIME MULTI- 37 . Pull the D ELAYED SWEEP knob out and tu rn it to PLI ER dial th roughout its range and notice that the disp lay switches between time bases at the point ind icated by the 50 μ s (D ELAY TIME remains at .5 ms) . Set the HO R IZ DELAY-TIME MULTI PL I ER dial . Retu rn the HO R IZ DIS- DISPLAY switch to Α ΙΝΤΕΝ D UR I N G Β . An intensified PLAY switch to Α . portion, about one division in length, should be shown at the start of the trace . Rotate the DELAY-TIME MULTI- PL I ER d ial through out its range ; the intensified portion Single Sweep shou ld move along the d isplay . 44 . Set the Α SWEEP MOD E switch to SI N G LE SWEEP . Remove the Cali brator signal from the C H 2 O R Υ connec 38 . Set the Β SWEEP MODE switch to TRIGGERABLE tor . Press the RESET bu tton ; the RESET light should come AFTER DELAY TIME . Again rotate the DELAY-TIME on and remain on . Again apply th e signal to the CH 2 OR Υ MULTI PL I ER dial throughout its range and note that th e connector ; α single trace sh oul d be p resented and the 2-1 0

can be demonstrated . Remove the grou nd strap between switch to AUTO T R IG . the Ζ AXIS I NPUT bind ing posts . Connect the external signal to both the CH 2 OR Υ connector and the Ζ AXIS External Horizontal I NPUT bind i ng posts . Set the Α ΤΙΜΕ/DIV switch to dis- play abou t five cycles of the waveform . T he positive peaks 45 . Connect the Calibrator signal to both the CH 2 OR of the waveform should be blanked and the negative peaks Υ and ΕΧΤ T R IG OR Χ I NPUT connectors . Set the Β intensifie d , ind icating intensity modulation . Replace the SOURC E switch to ΕΧΤ, Β COUPL ING switch to DC, and ground strap . the H OR IZ DISPLAY switch to Χ-Y . Increase the INTEN- SITY control setting until the display is visible (two d ots displayed diagonally) . The display should be five divisions 53 . Th is completes the basic operating vertically and about 3.7 divisions horizontally . Set the Β procedure for the 453Α . Instrument operations not explai ned here, or SOUR CE switch to ΕΧΤ - 10 . The d isp lay should be re- operations wh ich need further explanation are discussed duced 10 times horizontally . The display can be positioned un der General Operating Information . horizontally with the horizontal POSITIO N or F I NE con- trol, and vertically with the Channel 2 POSITIO N control. 46 . Con nect the Calibrator signal to both the CH 1 OR Χ and CH 2 OR Υ connectors . Set the ΙΝΤ T R IG switch to CH 1 OR Χ-Υ and the Β SOUR CE switch to INT . 47 . The display should be five divisions vertically and horizontally . The display can be positioned horizontally with the Channel 1 POSITION control and vertically with the Channel 2 POSITIO N control. 48 . Change the CH 1 VOLTS/DIV switch to .5 . The Simplified Operating Instructions display is reduced to two divisions h orizontally . Now set General . The following information is provided to aid in the CH 2 VOLTS/DI V switch to .5 . The d isp lay is reduced quickly obtaining th e correct setting for the 453Α to pre to two divisions vertically . sent α display . The operator should be familiar with the complete function and operation of the instrument as Beam F inder described in this section before using th is procedu re . 49 . Set the CH 1 and CH 2 VOLTS/DIV switches to 10 mV. The display is not visible since it exceed s the scan area Normal Sweep Display (Y -Τ Display) of the C RT. 50 . Press the BEAM F I NDER switch. Note that th e d is- ρΙαγ is returned to the graticule area . Wh ile holding the BEAM F I NDER switch dep ressed , increase the vertical and horizontal deflection factors until the display is reduced to about two d ivisions vertically and h orizontally. Adjust the Ch annel 1 and 2 POSITION controls to center the display about the center lines of the graticule. Release the BEAM F I NDER and note th at the d isplay remains within the view- ing area . Disconnect the app lied signal . 51 . R educe the I NTENSITY control setting to normal, Β SOURCE switch to ΙΝΤ, and set the HOR IZ DISPLAY switch to Α. Ζ-Axis Input 52 . If an external signal is available (five volts peak to peak minimum) the function of the Ζ AXIS I NPUT circu it 6. Connect the signal to the CH 1 OR Χ connector. Operating I nstructions-453A/ R453A TEST SET-UP CHART Fig . 2-5 shows the front, side, and rear panels of the 453Α. Th is chart can be reproduced and used as α test-setup record for special measurements, applications or p roce- dures, or it may be used as α training aid for familiarization with th is instrument. G ENERAL OPERATING I NFORMATIO N 1 . Set the INTEN SITY control fu lly counterclockwise . 2 . Set the Input Cou pling switch to AC, VAR VOLTS/ DIV control to calibrated, and vertical MOD E switch to CH 1 (use ALT or CHOP for dual-trace disp lay) . 3. Set the Α SWEEP MODE, Α S LOPE, Α CO UPLI N G, and Α SOURC E switches to their up positions. 4 . Set the Α ΤΙΜΕ/DIV switch to 1 ms/DIV, Α VAR ΤΙΜΕ/DI V control to calibrated , and HOR IZ DISPLAY switch to Α. 5. Set the POWER switch to ON . Allow several minutes warmup . 2- 1 1

2- 1 2 SERIAL STEP (((Πlll=ό`Ε POSITION AC GND DC NORM ΙΝΤ C H 1 TRIG TEKTRONIX . ΙΝ C ΒΕΑνΕ R ΤυΝ. OREGON, υ τΑ Β . Side panel 453ΑT EST SET-UP C HART DELAY TIME MULTIPLIER 1-10 Εν TRIG Ο Ρ Α AND Β ι ρ ΤΙΜΕ /DIV U OR 8 υ rv εη CAL AND DELAY TIME 50Ι Ι Ι Ι 5 ( Ο ® S .2 \ ~~ /2 70 1 ΟΜ D Ο INVERT PULL STEP Ο ALT L Ν Α. F ront panel 10 20/ 4 DIV Α SWEEP M ODE Θ ENDS Α~~~ FULL AUTO Π TRIG Α TRIGGERING RE ET F ig . 2-5. C . R ear panel Β TRIGGERING Ι οΕισ,ΥΕ D SWEEP) SLOPE COUPLING SOURCE LEVEL /Ο CΗ 1 '_~ + Ι AC ιΝΤ θ SWEEP MODE ROGISERABLE STARTS HOR12 DISPLAY Α ΙΝΤΕΝ ,~ 50 DURINGG Θ 13 οευΥεο Γ POWER ΟΝ S ΕΜ TRIG η LF LINE INPUT REJ ΗΕ XT REJ OC Ε %Τ Η 10 AFTER DΕΙΑ-4:~ AF ΤΕ R οΕΙΑν TIME TIME υτε α r ρισ DURING AND SOURCE ED 5 ΙΤΙΟΝΟ .4 Β L EVEL SLOPE COUPLING SOURCE LEVEL _ UNCAL CH 1 .- GN 2 10 5 Βω Urvcαι Θ NORM / Ο REDUCED \ + AC ΙΝΤ RΕου CED βΎ ALT TRIG + CH 1 AC GND DC REJ CHOP on SINGLE LINE Γ ΕΜ TRIG SWEEP INPUT ADD C H 2 20 \ Α , , ( 5ωεΕR 0j?

th e I NTENSITY control until α d isplay is 5 . Set the HO R IZ DISPLAY switch to Β (DELAYE D visible (if display is not visible with the I NTEN SITY con- SWEEP) . Delayed sweep rate is shown by the dot on the trol at mid range, press the BEAM F I N D ER switch and DELAYED SWEEP ( Β ΤΙΜΕ/DIV ) knob. ad just th e VO LTS/DI V switch until the d isp lay is reduced in size vertically ; then center th e com pressed d isp lay with the vertical and horizontal POSITION controls ; release the 6 . F or α delayed sweep display with less j itter, set the Β BEAM FI N D ER) . Set th e FOC US control for α well-defined S WEEP MOD E switch to T RIGGER ABLE AFT ER DELAY disp lay . TIME, all Β Triggering switches up, and adju st the Β LEVEL control for α stable display . 8 . Set th e VO LTS/DI V switch and vertical POSITION control for α display wh ich remains with in the graticule area vertically . Mixed Sweep Display (Y-Τ Display) 9 . Set th e Α LEVEL control for α stable disp lay . 10 . Set the Α ΤΙΜΕ/DI V switch and horizontal POSI- TION control for α display wh ich remains within the grati- cule area horizontally . Magnified Sweep Display (Y-Τ Display) 1 . Follow steps 1 - 10 for N ormal Sweep Display . 2 . Adjust the horizontal POSITIO N control to move the area to be magnified with in the center d ivision of the C R T . If necessary, change the ΤΙΜΕ/DI V switch setting so the comp lete area to be magnified is with in the center division . 3 . Set the MAG switch to Χ 10 and adjust the horizontal F I NE control for precise positioning of the magnified dis- play . Delayed Sweep Display (Y -Τ Display) 1 . Follow steps 1 - 10 for N ormal Sweep Display . Operating Instructions-453A/ R 453A 1 . F ollow steps 1 - 10 for Normal Sweep Disp lay . 2 . Set the Β SWEEP MODE switch to Β STARTS AFTER DELAY TIME, HO RIZ DISPLAY switch to M IX E D, and Α SWEEP LENGTH to FULL . 3 . Pull out the D ELAYED SWEEP ( Β ΤΙΜΕ/DI V ) switch and turn clockwise to obtain the amount of magnification desired. 4 . Adjust the DELAY-TIME MULTI PL I ER d ial to vary the amount of delay time before th e start of the magnified portion of the d isp lay . 5 . For mixed sweep d isp lay with less j itter, set the Β SWEEP MOD E switch to T R IGGER ABLE A FTER DELAY TIME, all Β Triggering switches up, and adjust the Β LEVEL control for α stable d isplay . Χ -Υ Display 1 . Set the I NTENSITY control fully cou nterclockwise . 2 . Set both In put Cou pling switches to AC and VA R 2 . Set the Β SWEEP MOD E switch to Β STA RTS VOLTS/DIV controls to calibrated . AFTER DELAY TIME, H O R IZ DISPLAY switch to Α ΙΝΤΕΝ D UR I NG Β , and the Α SWEEP LENGTH control to FULL . 3 . Set the ΙΝΤ TR IG switch to C H 1 OR Χ-Y, HOR IZ DISPLAY switch to Χ-Y, Β SO URCE switch to ΙΝΤ , the Vertical MODE switch to C H 2, and th e Β COUPL I N G 3 . Pull out the D ELAY E D SWEEP ( Β ΤΙΜΕ/DI V ) switch switch to DC . Center th e horizontal POSITION control . and turn clockwise so the intensified zone on the display is the desired length (intensified zone will be displayed in delayed form) . If an intensified zone is not visible, change 4 . Set the POWER switch to ON . Allow several minutes the I NT ENSITY control setting . warmu p. 4 . Adjust the DELAY-TIME MULTI PL I ER dial to posi- 5 . Connect th e Χ (horizontal) signal to the CH 1 OR Χ tion the intensified zone to the portion of the disp lay to be connector and the Υ (vertical) signal to the C H 2 O R Υ delayed . connector . 2- 1 3

is 2 . Set the TI ΜΕ/DIV switch to .2 ms . visible (if no display is visible, press the BEAM F INDER switch and adjust the CH 1 and CH 2 VOLTS/DIV switches until the display is reduced in size both vertically and hori- 3 . With the FOCUS control and ASTIG adjustment set zontally ; then center the comp ressed d isp lay with the CH 1 to midrange, adjust the INTENSITY control so the rising and CH 2 POSITION controls ; release the BEAM F INDER) . portion of the d isp lay can be seen . Set the FOCUS control for α well-defined d isplay . 4 . Set the ASTIG adjustment so the horizontal and verti- 7 . Set the CH 1 and CH 2 VOLTS/DIV switches and cal portions of the display are equally focused , but not POSITION controls for α display which remains within the necessarily well focused. graticule area (leave the horizontal POSITION control set to midrange) . CH 1 controls affect h orizontal deflection and CH 2 controls affect vertical deflection . 5 . Set the FOCUS control so the vertical portion of the trace is as thin as possible . Intensity Control 6 . Repeat steps 4 and 5 for best overall focus . M ake final The setting of the INTENSITY control may affect the check at normal intensity . correct focus of the display . Slight re-adjustment of the F OCUS control may be necessary when the intensity level is changed. To protect the CRT phosphor, do not turn the Graticule I NTENSITY control h igher than necessary to p rovide α satisfactory disp lay . The light filters reduce the observed The graticule of the 453Α is internally marked on the light output from the CRT . When using these filters, avoid facep late of the CRT to provide accurate, no-parallax advancing the INTENSITY control to α setting that may measurements . The graticule is marked with eight vertical burn the phosphor . When the h ighest intensity d isp lay is and 10 h orizontal d ivisions . Each d ivision is 0.8 centimeter desired, remove the filters and use only the clear faceplate square . In addition, each major division is divided into five protector . Apparent trace intensity can also be improved in minor d ivisions at the center vertical and horizontal lines. p such cases by reducing the ambient light or u sing α viewing The vertical gain and horizontal timing are calibrated to the hood . Also, be careful that the INTENSITY control is not graticule so accurate measurements can be made from the set too high when changing the ΤΙΜΕ/DIV switch from α wCRmi itT . The ϊΙΙυ Lοη UM of the control . lines can be varied fast to α slow sweep rate, or when changing to the external with T . SCAL Ε E Ι L . h orizontal mode of operation . Astigmatism Adjustment If α well-defined d isp lay cannot be obtained with the F OCUS control, adjust the ASTIG adjustment (side panel) as follows . NOΤΕ To check for proper setting of the ASTIG adjust- ment, slowly turn the FOCUS control through the optimum setting. If the ASTIG adjustment is cor- rectly set, the vertical and horizontal portions of the display will come into sharpest focus at the same position of the FOCUS control . This setting of the ASTIG adjustment should be correct for any display. However, it may be necessary to reset the FOCUS control slightly when the INTENSITY control is changed. Fig . 2-6 shows the graticule of the 453Α and defines the various measurement lines . The terminology defined here First Ninth division Center division vertical vertical vertical line line line 1 . Connect α 1 V Calibrator signal to either channel and set the VOLTS/DIV switch of that channel to p resent α two-division d isp lay . Set the MODE switch to display the channel selected . Fig . 2-6 . Definition of measurement lines on 453A graticule . 2- 1 4 Center horizontal line

in all discussions involving graticule measure- filter or clear facep late protector . It can be ordered by ments . Tektronix Part No . 378-0573-00 . I Trace Align ment Adjustment If α free-running trace is not parallel to the h orizontal graticule lines, set th e T R AC E ROTATION ad justment as follows . Position the trace to the center horizontal line . Adjust the TRACE ROTATION adjustment (side panel) so th e trace is parallel with the horizontal graticule lines . ι ι ι ι ι ι ι ι ι ι ι ι ι L ight F ilter The tinted filter provided with the 453Α minimizes light reflections from th e face of the CRT to improve contrast when viewing the display under h igh ambient light con- ditions . Α clear plastic faceplate protector is also provided with th is instrument for use when neither the mesh nor th e tinted filter is u sed. The clea r faceplate protector provides th e best d isp lay for waveform photographs . It is also pre- ferable for viewing h igh writing rate disp lays . To remove th e filter from th e C RT, press down at the bottom of th e frame and pull the top of the filter away from the C R T faceplate (see F ig . 2-7) . An optional mesh filter is available for use with th e 453Α (standard with MOD 163D) . This filter provides shielding against rad iated EMI (electro-magnetic interfer- ence) from the face of the CRT . It also serves as α light filter to ma ke th e trace more visible u nder h igh ambient ligh t cond itions . The mesh filter fits in place of th e tinted Fig . 2-7 . Removing the filter or faceplate protector . Operating Instructions-453Α/R453A Α filter or the faceplate protector shou ld be used at all times to p rotect the C RT faceplate from scratches . The faceplate protector and th e tinted filter mount in the same h older . To remove the light filter or faceplate p rotector from the holder, press it out to th e rear . They can be re- placed by snapp ing th em back into the holder . Beam Finder Th e BEAM F I ND ER provides α means of locating α dis- play which over-scans the viewing area either vertically or h orizontally . When the BEAM F I N D ER switch is pressed , the d isplay is com pressed with in the graticule area . To locate and re-position an over-scanned display, use th e following procedure : 1 . Press the BEAM F I N D ER switch . 2 . Wh ile th e BEAM F I NDER switch is held depressed, increase the vertical and horizontal deflection factors until the vertical d eflection is reduced to about two d ivisions and the horizontal deflection is reduced to about four divisions (the horizontal deflection need s to be reduced only when in the Χ -Υ mode of operation) . 3 . Adjust the vertical and h orizontal POSITION controls to center the disp lay about the vertical and horizontal cen- ter lines . 4 . Release the BEAM F I NDER switch; the display should remain with in the viewing area . Vertical Ch annel Selection E ith er of th e input channels can be used for single-trace d isplays . Apply the signal to the desired input connector and set the M OD E switch to display the channel u sed . How- ever, since CH 1 triggering is provided only in Channel 1 and the invert featu re only in Channel 2, the correct ch an- nel must be selected to take advantage of these features . For dual-trace displays, connect the signals to both input connectors and set the MODE switch to one of the dual- trace positions . Vertical Gain Adjustment To ch eck th e gain of either channel, set the VO LTS/D I V switch to 20 mV. Set the CA LI BR ATO R switch to .1 V and connect th e 1 kH z CAL connector to the input of the channel used . The vertical deflection shou ld be exactly five d ivisio ns . If not, adjust the front-panel GAI N adju stment for exactly five divisions of deflection . 2-1 5

quency response . Remember that α ground strap only α few if the gain of the two channels must be closely inch es in length can produce several percent of ringing matched (such as for ADD mode operation), the when operating at the h igher frequ ency limit of this system . ' adjustment procedure given in the Calibration section See you r Tektronix, Inc. catalog for characteristics and should be used. com patibility of probes for use with this system . The best measurement accuracy when using probes is In h igh-frequency applications requiring maximum over- provided if the GAIN adjustment is made with the probes all bandwidth, use coaxial cables terminated at both ends in installed (set the CA L I BRATOR switch to 1 V) . Th is com- their characteristic im pedance . See the d iscussion on coax- pensates for any inaccu racies of the probes . Also, to pro- ial cables in th is section for more information . vide the most accurate measurements, calibrate the vertical gain of the 453Α at th e temperature at which the measure- ment is to be made. H igh-level, low-frequency signals can be connected d irectly to the 453Α i nput connectors with sh ort un- shielded leads. Th is cou pling method works best for signals Ste p Attenuator Balance below about one kilohertz and deflection factors above one volt/division . When this method is u sed, establish α , To chec k the step attenuator balance of either channel, v common ground between the 453Α and the equipment set the Input Coupling switch to GND and set the Α under test . Attempt to position the leads away from any SWEEP MOD E switch to AUTO TR IG to provide α free- source of interference to avoid errors in the disp lay . If running trace. Change the VOLTS/DIV switch from 20 mV interference is excessive with unshielded leads, use α coaxial ' to 5 mV . If the trace moves vertically, adjust th e front- cable or α probe. panel ST EP ΑΤΤΕΝ BAL adjustment as follows (αΙΙοω at least 10 minutes warmup before performing th is adjust- ment) . Loading Effect of the 453Α As nearly as possible, simu late actual operating con- 1 . W ith the Input Cou pling switch set to GND and the ditions in th e equipment under test . Otherwise, the equ ip- VOLTS/DIV switch set to 20 mV, move the trace to the ment under test may not produce α normal signal . The center h orizontal line of the graticule with the vertical probes mentioned previously offer the least circuit load ing. POSITIO N control . See the probe instruction man ual for load ing characteristics of individual probes . 2. Set the VOLTS/DIV switch to 5 mV and ad just the STEP ΑΤΤΕΝ BAL ad justment to return the trace to the When the signal is coup led directly to the input of the center horizontal line . 453Α , the input im pedance is about one megohm paralleled by abou t 20 picofarads. When th e signal is cou pled to the input th rough α coaxial cable, the effective in put capaci 3. Recheck step attenu ator balance and repeat adjust- tance depends upon the type and length of cable used . See ment until no trace shift occurs as the VOLTS/DIV switch the following d iscussion for information on obtaining maxi- is changed from 20 mV to 5 mV. mum frequency response with coaxial cables . Signal Connections Coaxial Cable Considerations In general, probes offer the most convenient means of Th e signal cables used to connect the signal to the 453Α connecting α signal to the in put of the 453Α . Tektronix input connectors have α large effect on the accuracy of α 10Χ probes are also shielded to prevent pickup of electro- displayed high-frequency waveform . To maintain the high- static interference . Α 10Χ attenuator probe offers α high freq uency characteristics of the app lied signal, h igh-quality input impedance and allows the circuit under test to per- low-loss coaxial cable sh ould be used. The ca ble sh ould be form very close to normal operating cond itions . H owever, α terminated at the 453Α input connector in its characteristic 10Χ probe also attenuates th e input signal 10 times. Tek- im pedance . If it is necessary to use cables with differing tronix F ield Effect Transistor probe systems are available characteristic impedances, use su itable impedance-match ing which of fer the same high-inpu t im pedance as the 10Χ devices to provide the correct transition, with minimum probes. However, they are particularly u seful since they loss, from one impedance to th e other . provide wide-band operation while presenting low attenu- ation and low input capacitance . To obtain maximum band- wid th when using probes, observe the grounding consider- T h e ch aracteristic im pedance, velocity of propagation, ations given in the probe manual . T he probe-to-connector and n ature of signal losses in α coaxial cable are determined 2- 1 6

nector is internally disconnected, bu t not grounded, and Losses caused by energy dissipation in the dielectric are the inpu t circuit is held at grou nd potential . proportional to th e signal frequency . Therefore, much of the h igh-frequency information in α fast-rise pu lse can be lost in only α few feet of interconnecting cable if it is not The GND position can also be used to pre-charge the the correct type. To be su re of the h igh -frequency response cou pling capacitor to the average voltage level of the signal of the system when using cables longer th an about five feet, app lied to th e input connector. This allows measurement of observe the transient response of the 453Α and the inter- only the AC com ponent of signals having both AC and DC connecting cable with α fast-rise pulse generator (generator components. The pre-charging network incorporated in this risetime less than 0.5 nanoseconds) . unit allows the input-coup ling capacitor to charge to the DC source voltage level when the I n put Coup ling switch is set to GND . The procedure for using this feature is as Ground Considerations follows : R eliable signal measureme nts cannot be made unless both the oscillosco pe and th e unit under test are connected together by α common reference (ground ) lead in add ition to the signal lead or probe . Although the three-wire AC power cord provi des α common connection when used with equi pment with similar power cords, th e ground loop pro- d uced may make accurate measurements impossible . The ground stra ps su pplied with the probes provide an ade- q uate grou nd . The sh ield of α coaxial cable provides α com- mon ground when connected between two coaxial connec- tors (or with suitable adapters to provide α common ground ) . When using unsh ielded signal leads, α common ground lead should be connected from the 453Α chassis to the chassis of the equipment under test . In put Coupling The C h annel 1 and 2 Input Coupling switches allow α choice of input coupling meth ods. The type of d isplay desired and th e applied signal will determine the coupling to use. Th e DC Coupli ng position can be u sed for most app lica- tions . This position allows measurement of th e DC com- ponent of α signal . It must also be used to display signals below abou t 16 hertz as they will be attenuated in the AC position . 1 . Before connecting the signal containing α DC compo- nent to the 453Α in put connector, set the I nput Coupling switch to GND . Then connect the signal to the input con- nector . 2. Wait about one second for the coup ling capacitor to charge . 3. Set the Input Coupling switch to AC . The trace (dis- play) should remain on the screen so the AC component of the signal can be measu red in the normal manner . Deflection Factor O perating Instructions-453Α/ R453A The amount of vertical deflection produced by α signal is determined by the signal amplitude, the attenuation factor of th e probe (if used ), the setting of the VOLTS/DIV switch, and the setting of the VAR VOLTS/DIV control . The calibrated deflection factors indicated by the VOLTS/ DIV switches apply only when the VAR control is set to the cali brated position (fully counterclockwise) . The VAR VOLTS/DIV control provides variable (uncali- brated) vertical deflection between the calibrated settings of the VOLTS/DIV switch . The VAR control extends the maximum vertical deflection factor of the 453Α to at least 25 volts/division (10 volts position) . In the AC Cou pling position, th e DC component of the signal is blocked by α capacitor in the input circuit . The Dual-Trace Operation low-frequency response in the AC position is about 1 .6 hertz (-3 dB point) . Therefore, some low-frequency atten- Alternate Mode. The ALT position of the vertical M OD E uation can be expected near th is freq uency limit. Attenu- switch produces α d isplay wh ich alternates between Chan- ation in the form of waveform tilt will also appear in square nel 1 and 2 with each sweep of the CRT . Although the ALT waves wh ich h ave low-frequency components . The AC mode can be used at all sweep rates, the CHOP mode pro- coupling position provides the best d isplay of signals with α vides α more satisfactory display at sweep rates below about DC com ponent wh ich is much larger than the AC com po- 50 microsecon ds/division. At these slower sweep rates, nent, alternate mode switch ing becomes visually perceptible . The GND position provides α grou nd reference at the Proper internal triggering in the ALT mode can be input of the 453Α without the need to externally ground obtained in either the NORM or CH 1 OR Χ-Υ positions of the input connectors. The signal applied to the input con- the ΙΝΤ T R IG switch . When in the NORM position, th e 2- 1 7

provides α stable d isp lay of two u nrelated signals, but does not ind icate the time relationsh ip between the signals. In the CH 1 OR Χ-Υ position, the two signals are displayed showing true time relationsh ip . If the signals are not time related, th e Channel 2 waveform will be u nstable in the CH 1 OR Χ-Υ position . The following operating considerations and basic appli- cations may suggest other uses for th is feature. Chopped Mode. The CHOP position of the MOD E switch produces α disp lay which is electronically switched between chan nels. In general, the CHOP mode provides the 1 . If AC coup ling is desired , set the Channel 1 Input best display at sweep rates lower th an about 50 micro- Cou pling switch to AC and leave the Ch annel 2 Input Coup- secon d s/ d ivision, or whenever dual-trace, single-shot ling switch set to DC . When both Input Cou pling switches phenomena are to be displayed . At faster sweep rates the are set to DC, DC signal coupling is provided . chopped switching becomes apparent and may interfere with the display . Proper internal triggering for the CHOP mode is pro- vided with the ΙΝΤ TR IG switch set to CH 1 OR Χ-Y . If the N ORM position is used, the sweep circu its are triggered from the between-channel switch ing signal and both wave- forms will be unstable . External triggering provides the same result as CH 1 OR Χ-Υ triggering . Two signals wh ich are time-related can be displayed in the chopped mode showing true time relationshi p . If the signals are not time-related , the Channel 2 display will appear unstable . Two single-shot, transient, or random sig- nals which occu r within the time interval determined by the ΤΙΜΕ/DI V switch (10 times sweep rate) can be com pared using the CHOP mode. To correctly trigger the sweep for maximum resolution, the Ch annel 1 signal must precede the Channel 2 signal . Since the signals show true time relation- sh ip , time-d ifference measurements can be made. Channel 1 Output and Cascaded Operation If α lower deflection factor than provided by the VOLTS/DIV switches is desired , C hannel 1 can be used as α wide-band pream plifier for C hannel 2 . Apply the input signal to th e CH 1 OR Χ connector. Connect α 50-ohm BNC cable (18-inch cable for maximum cascaded frequency response) between the CH 1 OUT (sid e panel) and the CH 2 OR Υ connectors . Set the M ODE switch to CH 2 and the ΙΝΤ TRIG switch to N ORM . With both VOLTS/DIV switch es set to 5 mV , the deflection factor will be less th an one millivolt/division . To provide calibrated one millivolt/d ivision deflection factor, connect the .1-volt Calibrator signal to the CH 1 OR Χ connector. Set the CH 1 VOLTS/DIV switch to .1 and the CH 2 VOLTS/DIV switch to 5 mV . Adjust th e Channel 2 VAR VOLTS/DIV control to produce α display exactly five d ivisions in amplitude. The cascaded deflection factor is determined by d ividing the CH 1 VOLTS/DIV switch 2-18 setting by 5 (C H 2 VOLTS/DIV switch and VAR control remain as set above) . For example, with the CH 1 VOLTS/ DIV switch set to 5 mV, the calibrated deflection factor will be 1 mill ivolt/division ; CH 1 VOLTS/DIV switch set to 10 mV, 2 millivolts/division, etc. 4. The MOD E switch and Channel 1 VAR VOLTS/DIV control have no effect on the signal available at the CH 1 OUT connector . 6. The dynamic range of the Channel 1 In put Preamp is equal to about 20 times the CH 1 VOLTS/DIV setting. The CH 1 OUT signal is nominally at 0 volt DC for α 0 volt DC input level (Channel 1 POSITION con trol centered) . The Channel 1 POSITION control can be used to center the output signal with in the dynamic range of the am plifier . ι 2. Keep both vertical POSITION controls set near mid- range. If th e inpu t signal has α DC level which necessitates one of the POSITION controls being turned away from mid range, correct operation can be obtained by keeping the Channel 1 POSITION control near midrange and using the Channel 2 POSITION control to position the trace near the desired location . Then, use the Channel 1 POSITION con- trol for exact positioning. This method will keep both Input Preamps operating in their linear range. 3. The ou tput voltage at the CH 1 OUT connector is at least 25 millivolts/d ivision of CRT display in all CH 1 VOLTS/DIV switch positions . ι 5. The Ch annel 1 Input Preamp can be used as an imped - ance match ing stage with or without voltage gain . The inpu t resistance is one megohm and the outpu t resistance is about 50 ohms . ι ι 7. If dual-trace operation is used , the signal applied to the Channel 1 input connector is displayed when Channel 1 is tu rned on . When Ch annel 2 is turned on, the amplified signal is disp layed . Thus, Channel 1 trace can be used to monitor the input signal wh ile the am plified signal is d is- played by Channel 2.

3. Use vertical POSITIO N control settings wh ich most sponse of the 453Α is not desired , α filter inserted between nearly position the signal of each channel to mid-screen the CH 1 OUT and CH 2 OR Υ connector allows the when viewed in either the CH 1 or CH 2 positions of the oscillosco pe to essentially take on the frequency response M OD E switch. Th is insures th e greatest dynamic range for of the filter . Com bined with method 7, the input can be ADD mode operation . mon itored by Channel 1 and th e filtered signal displayed by Channel 2. 4. For similar response from each channel, set both I nput Coupling switches to the same position. 9. By using Channel 1 as α 5Χ low-level voltage p re- amplifier (5 mV position), the Channel 1 signal available at the CH 1 OUT connector can be used for any app lication Trigger Source where α low-impedance pream plified signal is needed . INT . For most applications, the sweep can be triggered Remember th at if α 50-ohm load impedance is used , the signal am plitude will be about one-half . internally . In the ΙΝΤ position of the Triggering SOURC E switch , the trigger signal is obtained from the Vertical Deflection System . The ΙΝΤ T R IG switch provides further Algebraic Add i tion selection of th e internal trigger signal ; obtained from the Channel 1 signal in the CH 1 OR Χ-Υ position, or from the General. The ADD position of the MOD E switch can be d isplayed signal when in the N ORM position. For single- used to d isplay th e sum or difference of two signals, for trace d isplays of either channel, the N ORM position pro- common-mode rejection to remove an undesired signal, or vides the most convenient operation. H owever, for dual- for DC offset (applying α DC voltage to one channel to trace d isplays special considerations must be made to pro- offset the DC component of α signal on the other channel) . vide the correct disp lay . See Dual-Trace Operation in th is section for dual-trace triggering information . The common-mode re jection ratio of the 453Α is greater than 20:1 at one kilohertz (at all deflection factors) for sig- LINE . The L INE position of th e SOURCE switch εοη- ηαΙ amplitu des up to eight times the VOLTS/DIV switch nects α sam ple of the power-line frequency to the Trigger setting . Higher re jection ratios can typically be ach ieved by Generator circu it . L ine triggering is useful when the input careful adjustment of the gain of eith er channel wh ile signal is time-related to the line frequency . It is also useful observing the displayed common-mode signal . for provid ing α stable d isplay of α line-freq uency com po- nent in α complex waveform . I Deflection Factor. The overall d eflection factor in the ADD position of the MODE switch when both VOLTS/DIV switches are set to the same position is the same as the deflection factor indicated by either VOLTS/DIV switch . The am plitude of an added mode disp lay can be determined d irectly from the resultant CRT deflection multiplied by the deflection factor ind icated by either VOLTS/DIV switch. However, if the CH 1 and CH 2 VOLTS/DIV switches are set to different deflection factors, resu ltant voltage is difficu lt to determine from the CRT display. In this case, the voltage am plitude of the resultant display can be determined accurately only if the amplitude of the signal applied to either channel is known. EXT. An external signal connected to the ΕΧΤ TR IG I NPUT connector can be used to trigger the sweep in the ΕΧΤ position of the Triggering SO URCE switch . The ex- ternal signal must be time-related to the displayed signal for α stable display. An external trigger signal can be used to provide α triggered d isp lay when the internal signal is too low in amplitu de for correct triggering, or contains signal components on wh ich it is not desired to trigger . It is also u seful when signal tracing in amp lifiers, phase-sh ift net- works, waveshap ing circuits, etc. The signal from α single point in the circuit under test can be connected to the ΕΧΤ TRIG I NPUT connector through α signal probe or cable . The'sweep is th en triggered by the same signal at all times and allows amplitud e, time -relationship or waveshape Precautions . The following general precautions shou ld be changes of signals at various points in the circuit to be observed when using the ADD mode. examined without resetting the trigger controls . 1 . Do not exceed the input voltage rating of the 453Α . ΕΧΤ - 10 . Operation in the ΕΧΤ - 10 position is the same as described for ΕΧΤ except that the external trigger- 2. Do not apply signals that exceed an eq uivalent of ing signal is attenuated 10 times. Attenuation of high- about 20 times the VOLTS/DIV switch setting . F or amplitude external triggeri ng signals is desirable to broaden example, with α VOLTS/DIV switch setting of .5, the volt- the range of the Triggering LEVEL control. When the age applied to that channel should not exceed about 10 COUPL I NG switch is set to LF REJ, attenuation is abou t volts. Larger voltages may distort the disp lay. 20:1 . 2-19

signals below about 30 kilohertz are attenuated . Therefore, General. F our methods of coupling the trigger signal to the sweep will be triggered only by the higher-frequency the trigger circuits can be selected with the Triggering components of th e signal . T h is position is particularly COUPLING switches . Each position permits selection or useful for provid ing stable triggering if the trigger signal rejection of the frequency com ponents of the trigger signal contains line-freq uency components. Also, in the ALT which can trigger the sweep. F ig . 2-8 graphically illustrates position of the MOD E switch , the LF REJ position pro- the band of frequ itchencies covered by each position of the vides the best display at high sweep rates when com paring COUPL I NG sw . two unrelated signals (I NT TR IG switch set to N ORM) . AC . The AC position blocks the DC component of the trigger signal . Signals with low-frequency components below about 30 hertz are attenuated . In general, AC coup- ling can be used for most applications . However, if the trigger signal contains unwanted components or if the sweep is to be triggered at α low repetition rate or α DC level, one of the remaining COUPL I NG switch positions will provide α better disp lay . DC . DC cou pling can be used to provide stable triggering , with low-frequency signals which would be attenuated in The triggering point in the AC position depends on th e the AC position, or with low-repetition rate signals . It can average voltage level of the trigger signal . If the trigger sig- also be used to trigger the sweep when the trigger signal nals occur in α random fash ion, the average voltage level reaches α DC level selected by the setting of the LEVEL will vary, causing the triggering point to vary also . This sh ift control . When using internal triggering, the setting of the of the triggering point may be enough so it is im possible to Channel 1 and 2 POSITIO N controls affects the DC trigger maintain α stable display . In such cases, use DC cou pling . level . 2-20 HF REJ. The HF REJ position passes all low-frequency signals between about 30 hertz and 50 kiloh ertz . DC is re jected and signals outside the given range are attenuated. When triggering from complex waveforms, this position is useful for provid ing stable d isplay of low-frequency com po- nents. έ~σφ oil " θ~ φ ~` :θ :;σC :σσσιισr~ 'φ~~ Γ Fig . 2-8 . Frequency range of each COUPL ING switch position . 50 kHz ι ι ι ι ι ι ι ι ι ι

triggering . It is particularly usefu l when setting up the trig- trace mode if the ΙΝΤ TR IG switch is set to NORM . If ger circuits when α trigger signal is available without α trace used, the sweep will trigger on the DC level of one trace and disp layed on the CRT and it also indicates that the Α sweep then either lock out completely or free run on the other remains correctly triggered when operating in the Β (DE trace. Correct DC triggering for this mod e can be obtained LAYED SWEEP) mode. with the ΙΝΤ TR IG switch set to CH 1 OR Χ-Y . Trigger Slope The triggering S LOPE switch determines whether the trigger circuit responds on the positive-going or negative- going portion of the trigger signal . When the SLOPE switch is in the + (positive-going) position, the d isp lay starts with the positive-going portion of the waveform ; in the - (negative-going) position, the display starts with the negative-going portion of the waveform (see Fig . 2-9) . When several cycles of α signal appear i n th e d isp lay, the setting of the S LOPE switch is often unimportant . H owever, if only α certain portion of α cycle is to be disp layed, correct setting of the S LOPE switch is imp ortant to provide α disp lay which starts on the desired slope of the input signal . Trigger Level Α Sweep Mode Operating Instructions-453Α/R453A AUTO TR IG . The AUTO T R IG position of the Α SWEEP MODE switch provides α stable d isplay when the Α LEVEL control is correctly set (see Trigger Level in th is section) and α trigger signal is available . The Α SWEEP TR IG'D ligh t ind icates when the Α Sweep Generator is trig- gered . When the trigger repetition rate is less than a bout 20 hertz, or in the absence of an adequate trigger signal, the Α Sweep Generator free runs to produce α reference trace. When an adequate trigger signal is again app lied , the free- running condition ends and the Α Sweep Generator is trig- gered to produce α stable display (with correct Α LEVEL control setting) . The Triggering LEVEL co ntrol determines the voltage level on the trigger signal at which the sweep is triggered. NORM TR IG . Operation i n the NORM TR IG position When the LEVEL control is set in the + region, the wh en α trigger signal is applied is the same as in the AUTO trigger circuit responds at α more positive point on the TR IG position . However, when α trigger signal is not pres- trigger signal . When the LEVEL control is set in the - ent, the Α Sweep Generator remains off and there is no region, the trigger circuit responds at α more negative display . The Α SWEEP TR IG'D light ind icates when the Α point on the trigger signal . F ig . 2-9 illustrates th is effect sweep is triggered . The NORM TR IG mode can be used to with different settings of the S LOPE switch . display signals with repetition rates below about 20 hertz . Th is mode provides an indication of an ad equate trigger signal as well as the correctness of trigger control settings, To set the LEVEL control, first select the Triggering since th ere is no disp lay without proper triggering . Also, the MODE, SOURC E, COUPL I N G, and SLOPE . Then set th e Α SWEEP T R IG'D light is off wh en the Α sweep is not LEVEL control fully counterclockwise and rotate itclock- correctly triggered . wise u ntil the display starts at the desired point. SINGLE SWEEP . When the signal to be displayed is not High-Frequency Stability repetitive or varies in amplitude, shape, or time, α conven- The HF STAB control (Α only) is used to provide α tional repetitive display may produ ce an unstable presenta- stable d isplay of h igh-freq uency signals . If α stable d isplay tion . To avoid th is, use the single-sweep feature of the cannot be obtained using the Α LEVEL control (trigger 453Α. T he SI NGLE SWEEP mode can also be used to signal must have adequate am plitude), adjust the HF STA B photograph α non-repetitive signal . control for minimum horizontal j itter in the display. This control has little effect with low-frequency signals . To use th e SI NG LE SWEEP mode, first make sure the trigger circuit will respond to the event to be d isplayed . Set Α Sweep Triggered L igh t the Α SWEEP MOD E switch to AUTO T R IG or NORM T R IG and obtain the best possib le display in the normal The Α SWEEP TR IG'D light provides α convenient indi- man ner (for random signals, set the trigger circuit to trigger cation of the cond ition of the Α Triggering circu it . If the Α on α signal wh ich is approximately the same amplitude and Triggering controls are correctly adj usted with an adequate frequ ency as th e rand om signal) . Then, set the Α SWEEP trigger signal applied, the light is on . H owever, if the Α M ODE switch to SI NGLE SWEEP and press the RES ET LEVEL control is misadjusted , the Α CO UPLI NG or Α button. When the RESET bu tton is pushed, the next trigger SOURCE switches incorrectly set, or the trigger signal too pulse initiates the sweep and α single trace will be presented low in amp litude, the Α SWEEP TR IG'D light will be off. on the screen . After th is sweep is com plete, the Α Sweep This feature can be u sed as α general indication of correct Generator is "locked ou t" until reset . Th e RESET light 2-21

SLOPE SLOPE F ig . 2-9 . E ffects of Triggering LEVEL con trol and SLOPE switch . Waveforms ob tain ed with the Triggering LEVEL con trol set in the+ region . Waveforms obtained with the Triggering LEVEL control set in the - region. _ Ι Positive "1 + 1 Slope ι ι Negative EmMisom ΜΕιιιιι

the RES ET button is on wh en th e Α Sweep Generator circuit has been reset and is ready to p roduce α sweep; it goes out after the sweep is com plete . To prepare the circuit for another single-sweep d isplay, press the RESET button again . H orizontal Sweep R ate The Α A ND Β TIME/DIV switches select cali brated sweep rates for th e Sweep Generators . The Α VA R and Β VA R IABLE controls provide continuously variable sweep rates between th e settings of the TIME/DIV switches . Whenever th e UNCAL Α OR Β ligh t is on, the sweep rate of either Α or Β Sweep Generator, or both , is u ncalibrated. The light is off when th e Α VA R (front panel) and Β TIME/ DI V VA R IA BLE (sid e panel) controls are both set to the calibrated position . The sweep rate of th e Α Sweep Generator is bracketed by the two black lines on the clear p lastic flange of th e TIME/DIV switch (see F ig . 2-10) . T he sweep rate of the Β Sweep Generator is indicated by the dot on the D ELAY E D SWEEP knob . When th e d ot on the outer knob is set to the same position as the lines on the inner knob , th e two knobs lock together and the sweep rate of bot h Sweep Generators is ch anged at the same time . However, when the D ELAYE D SWEEP knob is pulled outward, the clear plastic flange is disengaged and only the Β Sweep Generator sweep rate is changed . Th is allows changing the delayed sweep rate wit h - out changing the delay time determined by the Α Sweep Generator . Operating Instructions-453Α/R 453A First-division Nin th-division vertical line vertical line Time measureme n t area Fig . 2-11 . Area of graticule used for acc u rate time measuremen ts . When making time meas u rements from th e graticu le, the area between the first-division and ninth -d ivision vertical lines provides the most linear time measurement (see Fig . 2-11) . Th erefore, the first and last division of the d isp lay should not be used for mak ing accurate time meas u rements . Position th e start of the timing area to the first-division vertical line and set the TIME/DIV switch so th e end of the timing area falls between th e first- and ninth -d ivision verti- cal lines . Sweep Magnification The sweep magnifier expands th e sweep 10 times . The center division of the unmagnified d isplay is the portion visi ble on the screen in magnified form (see Fig . 2-12) . Equ ivalent length of th e magnified sweep is about 100 divi- sions ; any 10-d ivision portion may be viewed by adjusting the horizontal POSITIO N control to bring the desired por- tion onto the viewing area . The F I NE position control is particularly usefu l when the magnifier is on, as it provides positioning in small increments for more precise control . To use the magnified sweep, first move the portion of the disp lay wh ich is to be expanded to the center of th e graticule . Then set the MAG switch to X10 . The FINE position control can be adjusted to position the magnified display as desired . Th e light located below th e MAG switch is on whenever the magnifier is on . When the MAG switch is set to Χ 10, the sweep rate is determined by dividing the TIME/DIV switch setting by 10. For examp le, if the TIME/DIV switch is set to .5 μ s, the magnified sweep rate is 0.05 microsecond/division . The Fig . 2-1ο . Α AND Β TIME/DIV switch . magnified sweep rate must be used for all time measure- 2-23

2-24 - MAG switch set to Χ10 ι ~ L Fig . 2-12 . Operation of sweep magnifier . [H Magnified waveform SEENEEMENE MENNEENNEE "Γιr~ιΕ2CRΕ7 EMMMEENNNN FENNEEMENE MENEEMMEME Fig . 2-13 . (Α) Α ΙΝΤΕΝ DUR I NG Β display (Α ΤΙΜΕ/DI V, .5 ms ; Β ΤΙΜΕ/DIV, 50 μs), ( Β) Β (DELAYED SWEEP) display . ments when th e MAG switch is set to Χ10. The magnified sweep rate is calibrated when the UNCAL Α OR Β light is off. corresponds to 3 .55 CRT d ivisions of Α sweep. This reading multiplied by the setting of the Α ΤΙΜΕ/DIV switch gives Mixed and Delayed Sweep the calibrated delay time before the start of the Β sweep (see Β Sweep Mode which follows) . The intensified portion The delayed sweep ( Β sweep) is operable in the Α of th e d isplay is produced by the Β sweep. The length of ΙΝΤΕΝ DUR I NG Β, Β (D ELAY ED SWEEP), and MIX ED this portion is about 10 times the setting of the Β TIME/ positions of th e HO R IZ DISPLAY switch. The Α sweep DI V switch. rate along with the DELAY-TIME MULTI PL I ER dial set- ting determines the time th at the Β sweep is delayed . Sweep rate of the delayed portion is determined by the Β TIME/ When the HO R IZ DIS PLAY switch is set to Β (D E DI V (D ELAY ED SWEEP) switch setting . LAY ED SWEEP), only the intensified portion wh ich was shown in the A ΙΝΤΕΝ DUR I NG B position is displayed οη the screen at the sweep rate indicated by the Β ΤΙΜΕ/DIV In the Α ΙΝΤΕΝ DUR I NG Β position, the display will switch (see Fig. 2-13Β) . appear similar to Fig. 2-13Α. The amount of delay time between th e start of Α sweep and the intensified portion is determined by the setting of the Α ΤΙΜΕ/DI V switch and The MIX ED position of the HO R IZ DISPLAY switch the DELAY-TIME MULTI PL I ER dial . provides α C RT display containing more than one time factor on the horizontal axis . The first part of the d isp lay is at the sweep rate set by the Α ΤΙΜΕ/DIV switch and for For example, th e delay ind icated by th e DELAY-TIME th e time d uration determined by the setting of the DELAY- MULTIPL I ER dial setting shown in Fig. 2-14 is 3.55; th is TIME MULTI PL I ER dial.The latter part of th e display is at

ill u strates α typ ical mixed sweep disp lay . Β Sweep Mode . The Β SWEEP MOD E switch provides two modes of delayed sweep o peration . F ig . 2-16 illustrates the difference between these two modes . In th e Β STA R TS AFTER DELAY TIME position, the Β swee p is presented immediately after the delay time (see F ig . 2-16A) . The B sweep is triggered at α selected point on Α swee p to provide the delay time ( Β sweep essentially free running) . Since th e delay time is the same for each sweep, the d isplay appears stable . In the T R IGG ER ABLE AFT ER DELAY TIME position, the Β swee p operates only when it is triggered (by Trigger Circuits) after th e selected delay time (see F ig . ι ι ι ι ι ι Fig . 2-14 . DELAY-TIME MULTIPL IER dial . Reading shown : 3.55 . ι Α Sweep ι FE- (Delay) -1. ι ι Time ~k--(- Β Sweep Time ι ι Fig. 2-15 . Α typical mixed sweep display (Α ΤΙΜΕ /DI V set to 1 ms, Β ΤΙΜΕ/DIV set to .1 ms, and the DELAY-TIME MULTIPL I ER dial set to 3.55) . Operating Instructions-453Α/R 453A 2-16Β ) . The Β Triggering controls operate as d escribed in th is section . Delayed Sweep Operation . To obtain α delayed sweep display, use th e following p rocedure . 1 . Obtain α stable d isp lay with the H O R IZ DISPLAY switch set to Α . 2 . Set the HO R IZ DISPLAY switch to Α ΙΝΤΕΝ D UR- I N G Β . 3 . Set the Β SWEEP MOD E switch to the desired setting . If TR IGG ER ABLE A FTER DELAY TIME is selected, cor- rect Β Triggering is also necessary . 4 . Set the delay time with the Α ΤΙΜΕ /DIV switch and the DELAY-TIME MULTI PL I ER dial . 5 . Pull th e D ELAY E D SWEEP (Β ΤΙΜΕ/DI V ) knob out and set to th e d esired sweep rate . 6 . If the T R IGG ERABLE A FTER D ELAY TIME position is used, check the d isp lay for an intensified por- tion . Absence of the intensified zone indicates that Β sweep is not correctly triggered. 7 . Set th e HO R IZ DISPLAY switch to Β (D ELAYE D SWEEP) . The intensified zone shown in the Α ΙΝΤΕΝ D UR I N G Β position is now d isplayed at the sweep rate selected by the Β ΤΙΜΕ/DI V switch . Several examples using the delayed sweep feature are given under Basic App lications in th is section . Mixed Sweep Operation . To obtain α mixed sweep dis- play, use th e following procedure : 1 . Follow the proced ure given above for Delayed Sweep Operation . 2 . Set the ΗΟΒΙΖ DISPLAY switch to M IX E D . The first part of the d isplay is at the sweep rate set by the Α TIME/ DI V switch . The last part is at the sweep rate of th e Β ΤΙΜΕ/DI V switch . The DELAY-TIME MULTI PL I ER dial determines the point th at the sweep rate changes from Α to Β . Α Sweep Length . The Α SWEEP LENGTH control is most useful when used with d elayed sweep . As the control is rotated co u nterclockwise from the FULL position, the length of the Α sweep decreases (sweep rate remains con- stant) until it is about four d ivisions long in the cou nter- 2-25

Ι ~Ε Α sweep time 1 ~~Delay Ι ι Time ~1 Α sweep (Variable ~~starts Β sweep f rom 1 μs j i to 50 s by Ι ~Α ΤΙΜΕ/DIV Ι and Ι :DELAY-TIME',, I MULTIPL I ER) 1 -Ε}-Β sweep time / \ Α sweep / \ display 1 Delay __*j Α sweep Ι Time ;Ε"-- ""arms" Β sweep (Variable Ί Β sweep waits from 1 μs 1 0 for next trigger 1 to 50 s by Ι '-Ε-Β trigger pulse IA ΤΙΜΕ/DIV Ι 1 Ι and Ι I -Εε-Β sweep time (DELAY-ΤΙΜΕ ' ' Ί MULTI PL I ER): Ι 1 Α trigger Α trigger 1 Ι pulse pulse Ι 1 Ι Ι 1 1 1 1 1 ε ι / \ Ι A sweep MMMMAIEEI I- display I ntensified portion \\ Ί Intensified portion of waveform \\ of waveform Μ"""ΕΜ""Ε" "Η""ΕΜ"ΜΕ" Ν"""ΜΕ/""Μ "ΕΝΜΕΜ"Ε" W"""ΜΕ"""Ε Μ"""ΜΕΜ"ΜιΕ ΜΕΝΕΜ """" """"ΜΜ"""" Emmons """ΕΜ"""" ΜΕΝΕΜ = - . """"ΝI (Α) Β STARTS A FTER DELAY TIME (Β ) TR IGGERABLE AFTER DELAY TIME clockwise position (not in Β EN DS Α detent) . The Β EN DS time and delayed sweep rate in the normal manner . Tu rn Α position produces α d isplay which ends immediately the Α SWEEP LEN GTH control counterclockwise until the following Β sweep if the Β sweep ends before the normal sweep ends immediately following the intensified portion end of Α sweep. The Α SWEEP LEN GTH control is used to on the display . Now set the H OR IZ DISPLAY switch to Β increase the repetition rate of delayed sweep displays . (D ELAY E D SWEEP) . Th is method provides the maximum repetition rate for α given delayed sweep display . In the Β To use the Α SWEEP LEN GTH control, set the HO R IZ ENDS Α position, th e maximum delayed sweep repetition DISPLAY switch to Α ΙΝΤΕΝ D UR I N G Β and set the delay rate is maintained automatically . ι ι ι ι ι ι ι ι ι ι ι ι 'F ig . 2-16 . Com pa rison of delayed-sweep modes . (Α ) Β STARTS AFTER DELAY TIME, (Β ) TR IGGERABLE AFT ER DELAY TIME . In eac h display the Β sweep is delayed α selected amount of time by the Α sweep . ι ι

Intensity (Z-axis) modu lation can be used to relate α rect displays produced through the wrong usage of third item of electrical phenomena to the vertical (Y-axis) the Α SWEEP LENGTH control. When using this con- and the horizontal (X-axis) coordinates withou t affecting trol, first obtain the best possible display in the the waveshape of th e d isplayed signal . T he Z-axis modu- FULL position. Then, set the control for the desired lating signal app lied to the C R T circuit changes the inten- Α sweep length. If jitter is evident in the display, sity of th e d isplayed waveform to provide th is ty pe of dis- readjust the Triggering controls or change the Α play . "Gray scale" intensity modu lation can be obtained by SWEEP LENGTH control to α position that does not applying signals which do not com pletely blank the d isplay . cause jitter. Large am plitude signals of the correct polarity will com- p letely blank th e d isplay ; the sharpest display is provid ed by signals with α fast rise and fall . The voltage am p litude requ ired for visible trace mod ulation d epend s upon the set- Χ -Υ Operation ting of the INTENSITY control . At normal intensity level, In some applications, it is desirable to display one signal α five-volt peak-to-peak signal produces α visible ch ange in versus another (X-Y) rather th an against time (internal brightness . Wh en the Ζ AXIS I NPUT is not in use, keep the sweep ) . The Χ -Υ position of th e HO R IZ DISPLAY switch ground strap in place to prevent changes in trace intensity provid es α means for applying an external signal to th e due to extraneous noise . horizontal am plifier for th is type of display . Two modes of external horizontal operation are pro- vi ded . When the ΙΝΤ TR IG switch is set to CH 1 O R Χ-Y, the Β SO URC E switch to ΙΝΤ , and the Β COUPL ING switch to DC, the horizontal deflection is provid ed by α signal applied to the C H 1 O R Χ connector . The CH 1 VO LTS/DI V switch setting indicates the calibrated hori- zontal deflection factor (C hannel 1 VAR control inopera- tive) . Center the horizontal POSITIO N control and use the Channel 1 POSITIO N control for h orizontal positioning . In the ΕΧΤ and ΕΧΤ _ 10 positions of the Β SO UR CE switc h , external horizontal deflection is provid ed by α sig- nal ap plied to th e Β ΕΧΤ T R IG O R Χ I NPUT connector, The signal cou pling provided by the Β CO UPL I N G switch can be used to select or re ject com ponents of the external horizontal signal (all components of external horizontal sig- nal accepted in DC position) . Using th is mode of operation, the horizontal deflection factor is uncalibrated . External horizontal deflection factor is about 270 mill ivolts/clivision in the ΕΧΤ position of th e Β SOUR CE switch and about 2.7 volts/division in the ΕΧΤ : 10 position . F or fu rth er information on obtaining and interpreting lissajous d isplays, refer to th e reference book s listed und er App lications . Α and Β Gate The Α and Β GATE outp ut connectors (on side panel) provide α rectangular output pu lse wh ich is coincident with Current. The cu rrent loop, located on the sid e panel, the sweep time of th e respective sweep generator . Th is rec- p rovides α five milliampere peak-to-peak square-wave cur- tangular pu lse is abou t +12 volts in am plitude (into h igh - rent wh ich can be used to check and calibrate cu rrent- impedance loads) wit h pulse duration the same as the measuring probe systems . Th is current signal is obtained by respective sweep . clipping the probe arou nd the current loop . C u rrent is con- NO Τε Intensity Modulation Operating Instructions-453 Α/ R453A Time markers applied to the Ζ AXIS I NPUT connector provide α direct time reference on the disp lay . With uncali- brated horizontal sweep or external horizontal mode oper- ation, the time markers provide α means of reading time d irectly from the display . However, if the mark ers are not time-related to the displayed waveform, α single-sweep dis- play shou ld be used (for internal sweep only) to provide α stable display . Calibrator General . The one-kilohertz square-wave Calibrator of th e 453Α provides α convenient signal source for checking basic vertical gain and sweep timing . H owever, to provide maxi- mum measurement accuracy, the ad justment procedure given in the Calibration section of th is manual should be used. The Calibrator output signal is also very useful for adjusting probe compensation as d escribed in the probe instruction manual . In add ition, the Calibrator can be used as α convenient signal source for application to external equipment . Voltage . The Calibrator provides accurate peak-to-peak squ are-wave voltages of 0 .1 and 1 volt into α h igh imped- ance load . Voltage range is selected by th e CA L I BR ATO R switch on the sid e panel . Output resistance is about 200 ohms in the 1 V position and about 20 ohms in the 0 .1 V position . The actual voltage across an external load resistor can be calculated in the same manner as with any series resistor combination (necessary only if th e load resistance is less than about 50 kilohms) . 2-27

the CA L I- Rufus Ρ . Turner, "Practical Oscilloscope H andbook", BR ATOR switch . The arrow above the PROBE LOO P indi- Volumes 1 and 2, Joh n F. Rider Publisher Inc ., N ew York , cates conventional cu rrent flow ; i.e ., from + to - . 1964 . Freq uency . The Cali brator circu it uses frequency-stable Pea k-to-Peak Voltage Measurements-AC com ponents to maintain accurate frequency and constant duty cycle . Thus th e Calibrator can be used for chec k ing To ma ke α pea k-to-peak voltage measurement, use the the basic sweep timing of the horizontal system . following procedure : Waveshape . The square-wave outpu t signal of th e Cali- brator can be used as α reference waveshape when check ing or adju stin g th e compensation of passive, high-resistance probes . Since th e square-wave output from th e Calibrator has α flat top, any distortion in the displayed waveform is due to th e probe com pensation . The following information descri bes the proced ures and techniques for making measurements with α 453Α Oscillo- scope . These applications are not described in detail, since each application m u st be ada pted to the requirements of the ind ividual measu rement . Th is instrument can also be used for many applications wh ich are not described in th is manual . Contact your local Tektronix F ield Office or rep resentative for assistance in making specific measure- ments with th is instrument . The following books describe oscilloscope measurement tech niques wh ich can be adapted for use with this instru - ment . Harley Carter, "An Introd uction to the Cathode Ray Oscilloscope", Ph ilips Technical L ibrary, Cleaver-Hume Press L td., London, 1960 . J oh n F. Rider and Seymour D . Uslan, "E ncyclopedia of Cat h ode- R ay Oscilloscopes and Their U ses", John F . Rider Publisher Inc ., N ew York , 1959 . 2-28 1 . Connect the signal to either input connector . 2 . Set th e MOD E switch to d isplay th e channel used. 3 . Set the VOLTS/DI V switch to display about five d ivi- sions of the waveform . 4 . Set the Input Coup ling switch to AC . APPL ICATIO NS NOTE General For low-frequency signals below about 16 hertz, use the DC position . 5 . Set the Α Triggering controls to obtain α stable dis- play . Set th e ΤΙΜΕ/DI V switch to α position that displays several cycles of the waveform . 6 . Turn the vertical POSITION control so the lower por- tion of the waveform coincides with one of the graticule lines below th e center horizontal line, and the top of the waveform is on the viewing area . M ove the disp lay with the h orizontal POSITION control so one of the upper pea k s lies near th e center vertical li ne (see Fig . 2-17) . Position to center vertical line J . Czech , "Oscilloscope M easuring Technique", Ph ilips Technical Library, Springer-Verlag, New York , 1965 . Robert G . M idd leton, "Scope Waveform Analysis", H oward W . Sams & Co . Inc ., The Bobbs- Merrill Com pany Inc ., Ind ianapolis, 1963 . Robert G . Middleton and L . Donald Payne, " Using the Vertical deflection Oscilloscope in Industrial E lectronics', H oward W.Sams& Co . Inc ., The Bobbs-M errill Com pany Inc ., Indianapolis, 1961 . J oh n F. Rider, "Obtai n ing and Interpreting Test Scope Traces", Joh n F . Rider Pub lisher Inc ., New York , 1959 . Fig . 2-17 . Meas u ring peak-to-pea k voltage of α waveform .

to peak . Make sure the VA R VO LTS/DI V control is in th e cali brated position . To measure α voltage level with respect to a voltage rather than ground, make the following changes in step 6. Set the Input Coupling switch to DC and apply the reference voltage to the INPUT connector. Then position the trace to the reference line . This technique may also be used to make measure- ments between two points on the waveform rather than peak to peak. 7 . Set the Input Coup ling switch to DC . The ground reference line can be checked at any time by switch ing to the GN D position (except when using α DC reference volt- 8 . Mu ltiply the distance measured in step 7 by the age) . VO LTS/DIV switch setting . Also includ e the attenuatio n factor of the probe, if any . 8 . Set the Α Triggering controls to obtai n α stable dis- play . Set th e ΤΙΜΕ/DI V switch to α setting that displays Example . Assu me α pea k-to-peak vertical deflection of several cycles of the signal . 4.6 d ivisions (see F ig . 2-17) using α 10Χ attenuator pro be and α VOLTS/DIV switch setting of .5 . 9 . M eas u re the distance in divisions between the refer- ence line and th e point on the waveform at wh ich th e DC Using the formula : level is to be measured. For exam ple, in F ig . 2-18 th e vertical probe measurement is made between the reference line and point Volts VOLTS/DIV Α . Peak to Peak - deflection Χ setting Χ attenuation (divisions) factor Substituting the given values : ΝΟΤΕ Volts Peak to Peak = 4.6 Χ 0.5 V Χ 10 The peak-to-peak voltage is 23 volts . Operating Instructions-453Α / R453A NOΤΕ 10 . Establis h th e polarity of the signal . If the waveform is above the reference line, the voltage is positive ; below the line, negative (w h en th e I NVERT switch is push ed in if using C hannel 2) . 11 . Mu lti ply the distance measured in step 9 by the VO LTS/DI V switch setting . Include th e attenuation factor Instantaneous Voltage Measurements-DC of the probe, if any . To measu re the DC level at α given point on α waveform, use the following procedu re : 1 . Connect th e signal to either input connector . 2 . Set the MOD E switch to display the channel used . 3 . Set the VO LTS/DI V switch to disp lay about five divi- sions of the waveform . ENEEMSEEME /""ΝΕWιΕRΕ" ιΜι ιΜι ιΕR πm!ΕΝΝΝΝ NNENEENEWE 4 . Set the In put Coupling switch to G N D . Vertical distance 5 . Set the Α SWEEP MOD E switch to AUTO TR IG . 6 . Position the trace to the bottom line of the gratic u le Reference line or other reference line . If the voltage is negative with re- spect to ground , position the trace to the top line of the graticule . Do not move the vertical POSITIO N control after Fig . 2-18 . Measu ring in stantaneou s DC voltage wit h respect to α th is reference line has been established . reference . 2-29

Example . Assume that the vertical distance measure d is 3 . To establish an arbitrary vertical deflection factor so 4.6 d ivisions (see F ig . 2-18), the waveform is above the the amplitu de of an un k nown signal can be measu red accur- reference line, using α 10Χ attenu ator probe and α VO LTS/ ately at any setting of the VO LTS/DIV switch , the amp li DIV setting of 2 . tude of the reference signal must be known . If it is not known, it can be measu red before the VA R VO LTS/DI V Using th e formu la : control is set in step 2 . Instan- vertical VO LTS/ probe taneous = distance Χ polarity Χ DIV Χ attenuation 4 . Divide the amplitu de of th e reference signal (volts) by Voltage (d ivisions) setting factor the product of the vertical deflection estab lished in step 2 (divisions) and the setting of th e VO LTS/DI V switch . Th is Substituting the given values : is the vertical conversion factor . Instantaneous - 4.6X+1 Χ 2 V Χ 10 reference signal Voltage Vertical Conversion = am plitude (volts) Factor vertical VO LTS/D Ι V Factor The instantaneous voltage is +g2 volts . deflection Χ switch (d ivisions) setting Comparison Measurements General . In some applications it may be desirable to estab lish arb itrary units of measu re other than th ose indi- cated by the VOLTS/DIV switch or ΤΙΜΕ/DI V switch . Th is is particularly usefu l when com paring unknown signals to α reference am plitude or repetition rate . One u se for the com parison-measurement tech nique is to facilitate cali- bration of equipment (e.g ., on an assembly-line test) where the desired amp lit u de or repetition rate does not prod u ce an exact number of d ivisions of deflection . The adjustment will be easier and more accu rate if arbitrary units of meas- ure are establis h ed so that correct adjustment is indicated by an exact number of divisions of deflection . Arbitrary sweep rates can be useful for com paring harmonic signals to α fundamental freq uency, or for comparing the repetition rate of the input and output pu lses in α digital cou nt-down circuit . T he following procedure descri bes how to establish arbitrary units of measure for com parison measu rements . Alth ough the procedure for establish ing vertical and hori- zontal arbitrary u nits of measure is much the same, both processes are described in detail . Vertical Deflection Factor . To establis h an arbitrary vertical d eflection factor based upon α specific reference amp litude, proceed as follows : 1 . Connect the reference signal to the in pu t connector . Set the ΤΙΜΕ /DIV switch to display several cycles of the Vertical signal . Conversion = 30 V = 1 .5 2 . Set the V O LTS/DIV switch and the VA R VO LTS/ DIV control to produce α display an exact num ber of grati- cule divisions in am plitude . Do not change th e VA R VO LTS/DI V control after obtaining the desired deflection . Th is disp lay can be used as α reference for amplit u de com- parison measurements . 2-30 5 . To meas u re the amplitude of an unknown signal, dis- connect the reference signal and connect the un known sig- nal to the input connector . Set th e VO LTS/DI V switch to α setting th at provides su fficient vertical deflection to make an accurate measurement . Do not readju st the VA R VO LTS/D 1V control . 6 . Measure the vertical deflection in divisions and calcu- late the amplitu de of the unk nown signal using the follow- ing formula . VO LTS/DI V vertical vertical Signal = switch Χ conversion Χ deflection Amplitude setting factor (divisions) E XAMPLE : Assu me α reference signal am plitude of 30 volts, α VOLTS/DIV switch setting of 5 and th e VA R VO LTS/DI V control is adjusted to provide α vertical deflec- tion of four divisions . Su bstituting these values in the vertical conversion factor formula (step 4) : F actor 4 Χ 5 V Then, wit h α VOLTS/DI V switch setting of 10, the peak-to- peak amp litude of an un k nown signal wh ich produ ces α vertical deflection of five divisions can be determined by u sing the signal am plitude formula (step 6) : Signal = 10 V Χ 1 .5 Χ 5 = 75 volts Amplit ude

Sweep Rates . To establish an arb itrary horizontal sweep EXAMPLE : Assume α reference signal frequency of 455 rate based upon α specific reference frequency, proceed as hertz (repetition rate 2 .19 milliseconds), and α ΤΙΜΕ/DI V follows : switch setting of .2 ms, with the Α VA R ΤΙΜΕ/DI V control adjusted to provide α horizontal deflection of eigh t d ivi- 1 . Connect the reference signal to the input connector . sions . Substituting these values in the horizontal conversion Set the VOLTS/DIV switch for fou r or five d ivisions of factor formu la (step 4) : vertical deflection . H orizontal 2 .19 ms 2 . Set the ΤΙΜΕ /DIV switch and the Α VA R ΤΙΜΕ /DI V Conversion = 0.2 ms Χ 8 = 1 .37 control so one cycle of the signal covers an exact num ber of Factor horizontal divisions . Do not change the Α VAR ΤΙΜΕ/DI V control after obtaining the desired deflection . Th is display Then, with α ΤΙΜΕ/DI V switch setting of 50 μ s, th e repeti- can be used as α reference for frequency comparison meas- tion rate of an u n known signal which com pletes one cycle urements . in seven horizontal divisions can be determined by using the 3 . To establish an arb itrary sweep rate so th e repetition rate of an unknown signal can be measu red accu rately at any setting of the ΤΙΜΕ/DI V switch , the repetition rate of the reference signal must be known . If it is not known, it can be meas u red before the Α VA R ΤΙΜΕ /DIV switch is set in step 2 . 4 . Divide th e repetition rate of the reference signal (second s) by the product of the horizontal deflection estab- lish ed in step 2 (d ivisions) and th e setting of the ΤΙΜΕ/DI V switch . Th is is the h orizontal conversion factor . Horizontal reference signal Conversion = repetition rate (seconds) Factor horizontal ΤΙΜΕ /DIV deflection Χ switch ( divisions) setting 6 . M easure the horizontal deflection in d ivisions and calculate the repetition rate of th e un known signal using the following form ula : repetition rate formula (step 6) : Repetition = 50 μs Χ 1 .37 Χ 7 = 480 μ s Rate Th is answer can be converted to frequency by taking th e reciprocal of the repetition rate (see a pplication on Deter- mining F requency) . Time-Duration Measurements To measu re time between two points on α waveform, use the following procedure : 1 . Connect th e sign al to either input connector . 2 . Set the MOD E switch to display th e channel used . 5 . To measure the repetitio n rate of an un known signal, 3 . Set the VO LTS/DI V switch to display about five divi d isconnect the reference signal and connect th e u nknown sions of th e waveform . signal to the input con n ector . Set the TI ΜΕ/DI V switch to α setting that provides sufficient h orizontal deflection to make an accurate measu rement . Do not readjust the Α 4 . Set the Α Triggering controls to obtain α stable d is- VAR ΤΙΜΕ/DI V control . play . 5 . Set th e ΤΙΜΕ/DI V switch to th e fastest sweep rate th at d isplays less than eight divisions between th e time measu remen t points (see F ig . 2-19) . (See the topic entitled Selecting Sweep Rate in th is section concerning non- linearity of first and last divisions of d isplay .) ΤΙΜΕ/DI V h orizontal horizontal Repetition = switch Χ conversion Χ deflection Rate setting factor (divisions) 6 . Adjust the vertical POSITIO N control to move th e points between which the time measurement is made to th e NOTE center horizontal line . If the horizontal magnifier is used, be sure to use the magnified sweep rate in place of the Τ/ΜΕ/D/ V 7 . Ad ju st th e h orizontal POSITION control to center the switch setting. display with in the center eight divisions of the graticule . 2-3 1

2-32 F ig . 2-19 . Meas u ri ng the time du ration between points on α wave- form . 8 . Measure the h orizontal distance between the time measurement points. Be sure the Α VAR control is set to the calibrated p osition . 9 . Mu ltip ly the distance measured in step 8 by the set- ting of the ΤΙΜΕ/DIV switch . If sweep magnification is used , divide th is answer by 10 . h orizontal ΤΙΜΕ/DI V distance Χ setting Time Duration = (divisions) magnification Substituting the given values : U se th e following procedure : The time duration is 0.5 millisecond . 90% points on the waveform . periodically-recurrent signal is the reciprocal of the time du ration (period ) of one cycle . 1 . Measure the time d uration of one cycle of th e wave- form as described in the previous application . 2 . Take the reciprocal of the time duration to determine the frequency . Example . The frequency of the signal shown in F ig . 2-19 wh ich has α time duration of 0.5 millisecon d is : Frequency = 1 = 1 = 2 kHz time duration 0.5 ms R isetime Measurements R isetime measurements emp loy basically the same tech niques as time-du ration measurements . The main d iffer- ence is the p oints between wh ich the measurement is made . The following procedu re gives the basic method of measur- ing risetime between the 10% and 90% points of the wave- form . Falltime can be measured in the same manner on the trailing edge of the waveform . 1 . Connect the signal to eith er input connector . Example . Assume that the horizontal distance between the time measurement points is five d ivisions (see F ig . 2-19) and th e ΤΙΜΕ /DIV switch is set to .1 ms with th e magnifier off . 3 . Set the VO LTS/DI V switch and VAR V OLTS/DI V control to prod uce α d isplay an exact num ber of divisions Using the formu la : in am plitud e . 2 . Set th e MODE switch to display the channel u sed. 4 . Center the d isp lay about the center h orizontal line . 5 . Set the Α Triggering controls to obtain α stable dis- play . Time Duration = 5 Χ 0.1 ms 1 6 . Set th e ΤΙΜΕ/DIV switch to the fastest sweep rate that displays less than eight d ivisions between the 10% and Determining F requency 7 . Determine the 10% and 90% points on th e rising por- tion of the waveform . The fig u res given in Table 2-2 are for Th e time measurement technique can also be used to the points 10% up from the start of th e rising portion and measure the frequency of α signal . Th e frequency of α 10% down from th e top of the rising portion (90% point) .

10% point of the waveform to the first graticule line . F or Time-Difference Measurements example, with α five-d ivision display as sh own in F ig . 2-20, the 10% point is 0.5 division up from the start of the rising The calibrated sweep rate and dual-trace features of the portion . 453Α allow measurement of time d ifference between two separate events . To measure time d ifference, use th e follow- ing proced u re . 9 . Measure the horizontal d istance between the 10% and 90% points . Be sure th e Α VAR control is set to the cali- brated position . 10. Multiply the distance measured in step 8 by the setting of the ΤΙΜΕ/DI V switch . If sweep magnification is used, divide th is answer by 10 . Examp le . Assume that the horizontal d istance between the 10% and 90% points is four d ivisions (see Fig . 2-20) and the ΤΙΜΕ/DI V switch is set to 1 μ s with the MAG switch set to Χ 10 . 8 . If possib le, set the ΤΙΜΕ/DIV switch for α sweep rate which shows th ree or more d ivisions between the two wave- Fig . Ζ-20 . Measuring risetime . for um s. Vertical display (divisions) 10% and 90% points 4 0 .4 and 3.6 d ivisions 5 0 .5 and 4.5 d ivisions 6 0 .6 and 5.4 d ivisions 7 0 .7 and 6.3 d ivisions 8 0 .8 and 7 .2 d ivisions TABLE 2-2 ι Ι ι ι Horizon tal 1 d istance Ι Divisions vertically between 10% & 90% points _3 .2 _4 .0 _4 .8 _5 .6 6.4 Operating Instructions-453 Α/R453A Applying th e time duration form u la to risetime : horizontal ΤΙΜΕ /DIV d ista nce Χ R isetime setting _ (divisions) (Time Duration) magnification Su bstituting the given values : R isetime -- 4 Χ 1 μs 10 The risetime is 0 .4 microsecond. 1 . Set the Input Coup ling switches to the desired coup- ling positions . 2 . Set th e M OD E switch to either CH O P or ALT . In general, CH OP is more suitable for low-frequency signals and the A LT position is more su itable for h igh-frequency signals . M ore information on determining the mode is given under Dual-Trace O peration in th is section . 3 . Set the ΙΝΤ TR IG switch to CH 1 OR Χ-Y . 4 . Connect the reference signal to the CH 1 OR Χ con- nector and the comparison signal to CH 2 OR Υ connector . The reference signal shou ld precede th e com parison signal in time . Use coaxial cables or probes wh ich have equ al time 1-1-1 delay to connect the signals to the inpu t connectors . 5 . If th e signals are of opposite polarity, pull ou t th e I NVERT switch to invert the Channel 2 display (signal may be of opposite polarity due to 180° time difference ; if so take into account in final calcu lation) . 6 . Set the V O LTS/DIV switches to produce fou r or five- division d isplays . 7 . Set the Α LEVEL control for α stable display . 2-33

9 . Adjust the vertical POSITIO N controls to center each Substituting the given values : waveform (or the points on the d isplay between wh ich the measu rement is made) in relation to the center horizontal 50 μs Χ 4.5 line . Time Delay = 10 10 . Ad ju st the h orizontal POSITIO N control so the Channel 1 (reference) waveform crosses th e center h ori zontal line at α vertical graticule li ne . NOTE Do not use the MIXED position of the ΗΟR /Ζ DlS- 11 . Measure the horizontal difference between the Chan- PLAY switch to make time measurements with the nel 1 waveform and the Ch annel 2 waveform (see F ig . DELA Y-TIME MUL TIPL IER dial. /η th is mode, error 2-21) . is in troduced into the measurement due to the special relationship between the Α and Β sweeps . 12 . Mu ltip ly the measured difference by the setting of the ΤΙΜΕ/DI V switch . If sweep magnification is used, divide th is answer by 10 . Example . Assu me that the ΤΙΜΕ/DI V switch is set to 50 μs, the MAG switch to Χ 10, and the horizontal difference between waveforms is 4.5 d ivisions (see Fig . 2-21) . Using the formula : ΤΙΜΕ/DI V horizontal Χ difference setting (division s) 2 . Set the VO LTS/DI V switch to produce α display Time Delay = ρ magnification about four d ivisions in amplitude . Channel 1 ( reference) Channel 2 . . . MMMMMMMMMM 11ιιιΕιιι ιιιιιιιιι EMMMMMINNIMM MMMMMMENIMM M0 MMENIMM υ~. ι ι ι cαιαυκο~ The time delay is 22 .5 microseconds . Delayed Sweep Time Measurements T he delayed sweep mode can be used to make accurate time measurements . Th e following measurement determines the time d ifference between two pulses disp layed on the same trace . Th is application may also be used to measure time d ifference from two different sources (dual-trace) or to measure time duration of α single pulse . See Section 1 for measu rement accuracy . 1 . Connect the sign al to either in put connector . Set th e M OD E switch to d isplay th e channel used . 3 . Adju st th e Α Triggering controls for α stable d isplay . 4 . If possi b le, set the Α ΤΙΜΕ/DI V switch to α sweep rate which displays about eight d ivisions between the pulses . 5 . Set th e HOR IZ DISPLAY switch to Α ΙΝΤΕΝ D UR- I N G Β and the Β SWEEP M OD E switch to Β STA RTS AFTER DELAY TIME . 6 . Set the Β ΤΙΜΕ/DI V switch to α setting 1/100t h of the Α ΤΙΜΕ/DI V sweep rate . Th is produ ces an intensified portion about 0 .1 d ivision in length . ΝΟΤΕ Do not change the Α L EVEL control setting or the horizontal POSITION control setting in the following Fig . 2-21 . Measu ring time difference between two pulses . steps as the measurement accuracy will be affected. 2-34

Exam ple . Assume the first d ial setting is 1 .31 and the the intensified portion to the first pu lse . second d ial setting is 8.81 with the Α TI ΜΕ /DI V switch set to 0.2 microsecond (see Fig . 2-22) . 8 . Set the HO R IZ DISPLAY switch to Β (D ELAYED SWEEP) . 9 . Adj ust the DELAY-TI ME MULTI PL I ER d ial to move second first delay time the pu lse (or the rising portion) to the center vertical line . Time Difference = dial - dial Χ ( Α ΤΙΜΕ/DI V N ote the setting of the DELAY-TIME MULTI PL I ER dial . (delayed sweep ) setting setting setting) 10 . Turn the DELAY-TIME MULTI PL I ER dial clock - Substituting the given values : wise until the second pu lse is positioned to th is same point (if several pulses are displayed, ret u rn to the Α ΙΝΤΕΝ Time Difference= [8.81 - 1 .31] Χ 0.2 μs D UR I NG Β position to locate the correct pulse) . Again note th e dial setting . The time difference is 1 .5 microseconds . 11 . Subtract th e first d ial setting from the second and mu ltiply by the delay time shown by the Α ΤΙΜΕ/DI V switch . Th is is the time interval between the pulses . DELAY-TIME DELAY-TIME MULTIPLIER dial : MULTIPLIER dial : 1 .31 8.81 on ~000=0 NNNNEEN EN NNEEMENNNE EMMMMM MM MMMMMMMMMM 131111~ , !III Using th e formu la : Delayed Sweep Magnification Operating Instructions-453A/ R 453A The delayed sweep feature of th e 453Α can be used to provide h igher apparent magnification than is provided by th e MAG switch . The sweep rate of the DELAYE D SWEEP ( Β sweep) is not actually increased ; the apparent magnifi- cation is the resu lt of delaying the Β sweep an amou nt of time selected by the Α ΤΙΜΕ/DI V switch and the DELAY- TIME MULTI PL I ER d ial before th e d isplay is presented at the sweep rate selected by the Β ΤΙΜΕ/DI V switch . The following methods use the Β STARTS AFTER DELAY TIME position to allow the delayed portion to be posi- tioned with the DELAY-TIME MULTI PL I ER d ial . If there is too much jitter in the delayed d isplay, use the Triggered Delayed Sweep Magnification procedu re . 1 . Connect the signal to either input connector . Set th e MOD E switch to d isp lay th e channel used . 2 . Set the VOLTS/DIV switch to produce α d isplay about 4 d ivisions in amp litu de . 3 . Adju st the Α Triggering controls for α stable display . 4 . Set th e Α ΤΙΜΕ/DI V switch to α sweep rate which disp lays th e complete waveform . 5 . Set th e HO R IZ DISPLAY switch to Α ΙΝΤΕΝ D UR- I N G Β and the Β SWEEP M OD E switch to Β STARTS AFTER DELAY TIME . (Β ) Β (DELAYED SWEEP) display. 6 . Position the start of the intensified portion with the DELAY-TIME MULTIPL I ER dial to the part of the display Fig . 2-22 . Measuri ng time difference using delayed sweep . to be magnified . 2-35

fies the fu ll portion to be magnified . The start of the inten- sified trace will remain as positioned above . 8 . Set th e HO RIZ DISPLAY switch to Β (DELAY E D SWEEP) . 9 . Time measurements can be made from the d isplay in the conventional manner . Sweep rate is determined by the setting of th e Β ΤΙΜΕ/DI V switch . 10 . The apparent sweep magnification can be calculated by dividing the Α ΤΙΜΕ/DI V switch setting by the Β TIME/ DI V switch setting . Example . The apparent magnification of the display shown in F ig . 2-23 with an Α ΤΙΜΕ/DI V switch setting of .1 ms and α Β ΤΙΜΕ/DIV switch setting of 1 μs is : 2-36 Apparent Magnification - Α ΤΙΜΕ/DI V setting (delayed sweep) Β ΤΙΜΕ/DI V setting Substituting th e given val u es : Apparent 1 Χ 10-4 Magnification 1 Χ 10-6 The apparent magnification is 100 times . Triggered Delayed Sweep Magnification . The delayed sweep magnification method just described may produce too much j itter at h igh apparent magnification ranges . The T R IGG ER ABLE AFTER D ELAY TIME position of the Β SWEEP MODE switch provides α more stab le display since th e delayed display is triggered at th e same point each time . 1 . Set up the display as given in steps 1 throu gh 7 de- scri bed above . 2 . Set th e Β SWEEP MODE switch to T R IGG ERA BLE AF TER DELAY TIME . 3 . Adju st the Β LEVEL control so the intensified por- tion on the trace is stable . (If an intensified portion cannot be obtained, see step 4 .) Pu lse to be magn ified on MEN mom ΙNEEMEENEEN MENEEMENNE ENNEEMENOM (Α ) Α sweep d isplay . ιrι:ι...ι~ι ι NEENEENEEN (Β ) Delaye d sweep display . Fig. 2-23 . Using delayed sweep for sweep mag nification . dition cannot be remed ied with the Β Triggering controls or by increasing the d isp lay am plitude (lower VO LTS/DI V set- ting), externally trigger the Β sweep. 5 . When the correct portion is intensified , set the H O R IZ DISPLAY switch to Β (D ELAYE D SWEEP) . Slight re-adjustment of the Β LEVEL control may be necessary for α stable d isp lay . 6 . Measu rement and magnification are as described above . Displaying Complex Signals Using Delayed Sweep Complex signals often consist of α num ber of individ u al 4 . Inability to intensify the desired portion indicates events of differing am plitudes . Since the trigger circu its are that the Β Triggering controls are incorrectly set or the sensitive to changes in signal amp litud e, α stable display can signal d oes not meet the triggering requirements . If the con- normally be obtained only when the sweep is triggered by

may not prod uce the desired display of α lower am p litude event wh ich follows the triggering event . The delayed sweep feat u re provides α means of delaying the start of the Β sweep by α selected amount following th e event wh ich trig- gers th e Α Sweep Generator . Th en, the part of the wave- form wh ich contain s th e information of interest can be displayed . Use the following p rocedure : 1 . Connect the signal to either input connector . Set the MODE switch to display the channel u sed . 2 . Set th e VO LTS/DI V switch to produce α disp lay about four d ivisions in amp litude . 3 . Adjust the Α Triggering controls for α stable display . 4 . Set the Α ΤΙΜΕ/DI V switch to α sweep rate wh ich displays the complete waveform . 5 . Set the HO R IZ DISPLAY switch to Α ΙΝΤΕΝ D UR- I N G Β and the Β SWEEP MODE switch to Β STA R TS A FTER D ELAY TIME . 6 . Position the start of the intensified portion with the DELAY-TIME MULTI PL I ER dial to the part of the display to be magnified . 7, Set the Β ΤΙΜΕ/DI V switch to α setting which inten- sifies the fu ll portion to be magnified . The start of the intensified trace will remain as positione d above . Operating Instructions-453Α/R453A MENEEMENNE MENEEMEEME EMEEMOMMMM ONNOMMUNNE 0rιιιιυ6ίNοWi rι i" EMENSEEMEN (Α) Th is portion of display cannot be viewed ade- quately because Α sweep is triggered on larger amp li- tude sign als at start of d isplay . MENNEEMENE NEENEEMMMM MMMMMMMMMM suffiammmmmm ΜΜΜΜO-ιιιιΜΜΜ !"lUl"ΜΜ""/" EMBEEMENNE NEENEEMENE (Β ) Area of interest displayed by delaying Β sweep (Β STARTS AFTER DELAY TIME mode) . F ig . 2-24 . Displaying α complex signal u si ng delayed sweep . Pulse Jitter Measurements 8 . Set the HOR IZ DISPLAY switch to Β (DELAYE D SWEEP) . In some applications it is necessary to measure the amount of j itter on th e leading edge of α pulse, or j itter between pulses . 9 . Time measurements can be made from the display in the convention al manner . Sweep rate is determined by the setting of th e Β ΤΙΜΕ/DI V switch . U se the following procedure : 1 . Connect the signal to either input connector . Set the Exam ple . F ig . 2-24 shows α complex waveform as d is- MODE switch to disp lay the channel used . played on the CRT . The circled portion of the waveform cannot be viewed in any greater detail because the sweep is triggered by the larger am plitude pu lses at the start of the 2 . Set the VO LTS/DI V switch to display about four d isplay, and α faster sweep rate moves th is area of the wave- divisions of the waveform . form off the viewi ng area . The second waveform shows the area of interest magnified 10 times using Delayed Sweep . The DELAY-TIME MULTI PL I ER dial has been adjusted so 3 . Set the Α ΤΙΜΕ/DIV switch to α sweep rate wh ich the delayed sweep starts just before the area of interest . displays the comp lete waveform . 2-37

4 . Set the Α Triggering controls to obtain as stable α d isp lay as possib le . 5 . Set the H OR IZ DISPLAY switch to Α ΙΝΤΕΝ DUR- I NG Β and th e Β SWEEP MODE switch to Β STARTS AFTER DELAY TIME . 6 . Position the start of the intensified portion with the DELAY-TIME MULTI PL I ER dial so the pulse to be meas- ured is intensified . 7. Set the Β ΤΙΜΕ/DIV switch to α setting wh ich inten- sifies the full portion of the pu lse th at shows j itter. 8 . Set the H O R IZ DIS PLAY switch to Β (DELAYE D Fig . 2-25 . Meas u ring pu lse jitter . SWEEP) . 9 . Pulse j itter is shown by horizontal movemen t of the pu lse (ta k e into account inherent j itter of Delayed Sweep) . M easure the amount of horizontal movement . Be sure both variab le controls are set to the calibrated position . 10 . M ultiply th e d istance measured in step 11 by the Β ΤΙΜΕ/DI V switch setting to obtain pu lse jitter i n time . Example . Assu me that the horizontal movement is 0.5 division (see F ig . 2-25), and the Β ΤΙΜΕ/DIV switch setting is .5 μs . U sing the form ula : 6 . The du ration of the Β GAT E signal is determined by Su bstitu ting th e given val u e : the setting of the Β ΤΙΜΕ/DI V switch . Pulse Jitter = 0.5 Χ 0.5 μs 7 . The external equipment will be triggered at the start The pu lse jitter is 0.25 microsecond . of the intensified portion if it responds to positive-going 2-38 Delayed Trigger Generator The Β GAT E ou tput signal can be used to trigger an external device at α selected delay time after the start of Α Sweep . The delay time of the Β GATE ou tpu t signal can be selected by the setting of the DELAY-TIME MULTIPL I ER dial and Α ΤΙΜΕ/DI V switch . Α Sweep Triggered Internally . When Α sweep is triggere d internally to p roduce α normal display, the delayed trigger may be obtained as follows . 1 . Obtain α triggered disp lay in the normal manner . 2 . Set the HO R IZ DISPLAY switch to Α ΙΝΤΕΝ D UR- ING Β . 3 . Select the amou nt of delay from the start of Α Sweep with the DELAY-TIME MULTI PL I ER dial . Delay time can be calculated in the normal manner . 4 . Set the Β SWEEP M OD E switch to Β STA RTS AF TER DELAY TIME . horizontal Β ΤΙΜΕ/DI V Pu lse J itter = j itter Χ setting 5 . Connect the Β GATE signal to the external equip- (d ivisions) ment .

if it re- nals may be of opposite polarity d ue to 180° phase differ- sponds to negative-going triggers . ence ; if so, take th is i n to account in the final calculation .) Α Sweep Triggered Externally . Th is mode of operation 6 . Set th e C H 1 and C H 2 VO LTS/DI V switches and the can be used to prod u ce α d elayed trigger with or wit h out α VA R VO LTS/DI V controls so the disp lays are equal and corresponding d isplay . Connect th e external trigger signal about five d ivisions in am plitude . to th e Α ΕΧΤ TR IG I NPU T connector and set the Α SO URCE switch to EXT . F ollow the operation given above to obtain the delayed trigger . 7 . Set the triggering controls to obtain α sta ble display . Normal Trigger Generator 8 . Set the ΤΙΜΕ/DI V switch to α sweep rate wh ich dis- Ordinarily, the signal to be displayed also provides the plays about one cycle of the waveform . trigger signal for the oscilloscope . In some instances, it may be desirable to reverse th is situ ation and h ave the oscillo- 9, Move th e waveforms to the center of th e graticule scope trigger th e signal source . Th is can be d one by connec- w it h th e vertical POSITION controls . ting th e Α GATE signal to th e input of the signal sou rce . Set the Α LEVEL control fully clockwise, Α SWEEP M OD E switch to AUTO TR IG, and adju st the Α ΤΙΜΕ/DI V switch 10 . Turn the Α VA R control until one cycle of the for the desired display . Since the signal source is triggered α signal that h as α fixed time relations h ip to the sweep, reference signal (Channel 1) occup ies exactly eight d ivisions by the output of the signal source can be displayed on the horizontally (see F ig . 2-26) . Each division of th e gratic u~le CRT as th ou gh the 453Α were triggered in the normal man- rep resents 45 of th e cycle (360 - 8 divisions = 45 / division) . (th is meth od d oes not allow selection of trigger level or ision) . The sweep rate can be stated in terms of degrees as 45/division . co u pling) . 11 . Measu re th e horizontal d ifference between corre- Multi-Trace Phase Difference Measurements spond ing points on the waveforms . Phase comparison between two signals of the same fre- quency can be made using the d u al-trace feat u re of the 453Α . Th is meth od of phase difference measurement can be used up to the frequency limit of the vertical system . To ma k e the comparison, use the following procedu re . 1 . Set the In put Coupling switches to the same position, depend ing on the type of cou pling desired . Channel l Channel2 2 . Set th e M OD E switc h to either CH O P or ALT . In (refere nce) (lagging) general, C HOP is more suitable for low-frequency signals and th e A LT position is more suitable for h igh-frequency signals . M ore information on determining the mode is given u nd er Dual-Trace Operation in th is section . 22 3 . Set the ΙΝΤ T R IG switch to C H 1 O R Χ-Y . 4 . Connect the reference signal to the CH 1 OR Χ con- nector and the comparison signal to the C H 2 O R Υ con- nector . The reference signal should precede the com parison signal in time . U se coaxial cables or probes wh ich have equal time d elay to connect the signals to the input connec- tors . 5 . If th e signals are of opposite polarity, pull the I NVER T switch out to invert the Channel 2 display . (Sig- F ig . 2-26 . Meas uring phase difference . Operating Instructions-453 Α/R453A 12 . Mu lti ply the measu red d istance (in d ivisions) by 45°/d ivision (sweep rate) to obtain the exact amount of phase d ifference . ι ι ι ι ι ι ι Horizon tal ι ι Differe nce ι ι 8 Division s ι Ί (360°) 1 1 2-39

Example . Assume α horizontal difference of 0.6 division Sub stituting the given valu es : with α sweep rate of 45°/division as shown in Fig . 2-26 . Phase Difference = 6 Χ 4.5 ° U sing the form u la : The phase difference is 27 ° . horizontal Ph ase Difference = difference Χ sweep rate (d ivisions) (degrees/div) X-Y Phase Measurements Su bstituting the given values : Phase Difference = 0 .6 Χ 45° The phase difference is 27 ° . H igh Resolution Phase Measurements More accurate d u al-trace phase measurements can be made by increasing the sweep rate (without changing the Α VA R control setting) . One of the easiest ways to increase th e sweep rate is with the MAG switch . Delayed sweep magnification may also be u sed. Th e magnified sweep rate is determined by d ividing the sweep rate obtained previ- ously by the amoun t of sweep magnification . Example . If th e sweep rate were increased 10 times with the magnifier, th e magnified sweep rate would be 45°/ division _ 10 = 4.5 ° /d ivision . F ig . 2-27 shows the same signals as used in F ig . 2-26 but with the MAG switch set to Χ 10 . W it h α horizontal difference of six divisions, the phase difference is : 2-40 horizontal magnified Phase Difference = difference Χ sweep rate (division s) (degrees/div) Channel l (reference) Channel 2 ιFΑ,ι'ιιι~!==FAOMM MEMOME EMENEEMEME MOMMEMEMEM Ι Ι .6 Horizon tal 01 Ι difference Ι F ig . 2-27 . High resolution phase-difference measu rement with i n- creased sweep rate . Th e X-Y ph ase measuremen t meth od can be used to measure th e phase d ifference between two signals of the same frequency . Th is meth od provides an alternative meth od of measurement for signal frequencies up to about 100 kilohertz . H owever, above th is frequency the inherent phase d ifference between the vertical and horizontal sys- tems makes accurate phase measu reme nts difficult . In th is mode, one of the sine-wave signals provides h orizontal deflection ( Χ ) wh ile the oth er signal provides the vertical deflection ( Υ ) . The phase angle between th e two signals can be d etermined from the lissa jous pattern as follows : 1 . Connect one of the sine-wave signals to both the CH 1 OR Χ and th e CH 2 O R Υ connectors . (N ote : steps 1 through 5 measure inherent ph ase d ifference between the Χ and Υ amplifiers to provide α more accurate X-Y phase measurement ; not necessary below abou t 1 kHz) . 2 . Set the HO R IZ DISPLAY switch to Χ-Y . Set th e ΙΝΤ T R IG switch to CH 1 O R X-Y and the Β SOUR CE switch to Ι NT . 3 . Position th e d isplay to the center of the screen and adjust the VO LTS/DI V switches to produce α display less than six d ivisions vertically (Υ ) and less than 10 divisions h orizontally ( Χ ) . The CH 1 VO LTS/DI V switch controls the horizontal deflection (Χ ) and the CH 2 VO LTS/DI V switch controls the vertical deflection ( Υ ) . 4 . Center th e display in relation to the vertical graticule line . M easure th e distances Α and Β as sh own in F ig . 2-28 . Distance Α is th e h orizontal measurement between the two points wh ere the trace crosses the center horizontal line . Distance Β is the maximum h orizontal width of the d isplay. 5 . Divide Α by Β to obtain the sine of the phase angle (φ ) between the two signals . The angle can then be obtained from α trigonometric table . Th is is the inherent phase sh ift of the instrument . 6 . Connect th e Υ signal to CH 2 O R Υ connector . Repeat steps 2 th rough 5 to measure phase angle . If th e d isp lay appears as α diagonal straight line, th e two signals are either in phase (tilted u pper righ t to lower left) or 180 ° out of phase (tilted u pper left to lower righ t) . If th e d isplay

MEMEMEMEME 7 . Subtract the inherent phase sh ift from the phase angle φ to obtain the actual phase difference . Example . Assume an inherent phase difference of 2° with α d isplay as shown in F ig . 2-28 where Α is 5 divisions and Β is 10 d ivisions . U sing the formula : is α circle, the signals are 90° out of phase . F ig . 2-29 shows the lissa j ous d isp lays produced between 0° and 360° . From the trigonometric tables : Notice th at above 180° phase sh ift, the resu ltant disp lay is the same as at some lower angle . φ = 300 Sub stituting the given val u es : Sine 0 = ό = 0.5 Operating Instrucltions-453Α/R453A Sine φ = ΑΒ F ig . 2-29 . Phase of lissa jous d isplay . (Α ) 0° or 360° , (Β ) 30 ° or 330 ° , (C) 90' or 270 ° , (D) 150 ° or 210 ° , ( Ε ) 180° . 2-41

Common- Mode Re jection 5 . Set the ΙΝΤ T R IG switch to NO RM . The ADD feature of th e 453Α can be u sed to display signals wh ich contain undesirable components . These und esirable com ponents can be eliminated through common-mode rejection . The precautions given under Alge- braic Add ition sh ou ld be observed . 1 . Connect the signal containing both the desired and undesired information to the C H 1 O R Χ connector . 2 . Connect α sign al similar to the unwanted portion of the Channel 1 signal to the C H 2 O R Υ connector . For exam p ie, in Fig . 2-30 α line-freq ue ncy sign al is co nnected to Channel 2 to cancel out the line-frequency component of the Channel 1 signal . 6 . Set the MOD E switch to ADD . Pull the I NVER T switch so the common-mo de signals are of opposite polar- ity . 7 . Ad just th e CH 2 VOLTS/DI V switch and CH 2 VAR control for maximum cancellatio n of the common-mode signal . 8 . The signal wh ich remains shou ld be only the desired portion of the Chan nel 1 signal . The u ndesired signal is cancelled ou t. 3 . Set bot h I nput Coupling switch es to DC (AC if DC Example . An examp le of th is mode of operation is component of input signal is too large) . shown in Fig . 2-30 . Th e signal applied to Chann el 1 con - tains unwanted line-frequency components ( F ig . 2-30Α ) . Α corresponding line-frequ ency signal is connected to Channel 4 . Set the MODE switch to A LT . Set the VO LTS/DI V 2 ( Fig . 2-30Β ) . F ig . 2-30C shows the desired portion of the switches so the signals are about equ al in am plitude . signal as d isplayed wh en common-mode re jection is used . MEMMEMEMOM MEMMEMEMEMEMEMEMEMS WMΕιιιι =WDEιER N-0 ----. ιιίιιιιιιι ιιιιιιιιιι ιιιιιιιιιι ιιιιιιιιιι NOONιιιιιι ιιιιιιιιιι Fr LL - Fig . 2-30 . Usi ng the ADD feat ure for common-mode re jection . (Α ) Channel 1 sig n al con tains desired information along with line-frequency com ponen t, (Β ) Channel 2 sig n al contains line-frequency only, (C) CRT display u sing common -mode re jection .

453Α/R453A Introduction Axis Am plifier circuit to b lank out the between-cha nn el switch ing transients when in the chopped mode of opera- tion . Α trigger-p ickoff stage at the output of the V ertical circuitry used in the 453Α Oscilloscope . The description Switching circuit p rovid es α sam ple of the displayed begins with α d iscussion of the instrument using the basic signal(s) to the Trigger Preamp circuit . block d iagram shown in Fig . 3-1 . Then , eac h circuit is describe d in detail, using α d etailed block d iagram to show the interconnections between the stages in eac h major cir- cuit and the relations hip of th e front-panel controls to the The output of the Vertical Switching circuit is con ind ivid ual stages . nected to the Vertical Output Amplifier through the Delay Line . The V ertical Output Am plifier circuit provides the final amplification for the signal before it is connected to Α com plete block d iagram is located in the Diagrams the vertical deflection plates of the C RT . T h is circuit in- section at the rear of th is manual . T h is block d iagram shows cludes the BEAM FIN DER switch wh ich com presses the the overall relationsh i p between all of the circuits . Com- vertical and horizontal deflection with in the viewing area to plete schematics of each circuit are also given in the Dia- aid in locating an off-screen display . grams section . Refer to these diagrams throughout the following circuit d escription for electrical values and relationsh ip . T he Trigger Preamp circuit provides am plification for the internal trigger signal selected by the ΙΝΤ TR IG switch . Th is internal trigger signal is selecte d from either the BLOCK DIAG R AM Chann el 1 Vertical Pream p circuit or the Vertical Switch ing circuit . O utput from th is circuit is connected to the Α Trig- General ger Generator circuit and the Β Trigger Generator circuit . The following discussion is provided to aid in und er- stand i ng the overall concept of the 453Α before the ind i- The Α and Β Trigger Generator circuits prod uce an out- vid ual circuits are discussed in detail . Α basic block d iagram put pulse wh ich initiates the sweep signal prod uced by the of the 453Α is shown in F ig . 3-1 . Only the basic inter- Α or Β Sweep Generator circuits . The in put signal to the Α connections between the ind ividual block s are shown on and Β Trigger Generator circuits can be ind ivid ually selec- th is d iagram . Each b lock represents α major circuit within ted from the i nternal trigger signal from the Trigger Preamp th is instrument . T he number on each block refers to the circuit, an external signal applied to the ΕΧΤ T R IG I NPU T com plete circuit diagram w h ich is located at the rear of th is connector, or α samp le of the line voltage app lied to the manual . instrument . Each trigger circu it contains level, slope, coupling, and source controls. Signals to be d isplayed on the C RT are app lied to either the CH 1 O R Χ a nd /or the CH 2 OR Υ connectors . The The Α Sweep Generator circuit prod uces α linear saw- in put signals are then amplified by the Channel 1 Vertical tooth output signal when initiated by the Α Trigger Gen- Pream p and/or the Channel 2 Vertical Preamp circuits . erator circuit . The slope of the sawtoot h produced by the Α Each Vertical P reamp circuit includes separate vertical de- Sweep Generator circuit is controlled by the Α ΤΙΜΕ/DI V flection factor, position, input coupling, gain, variable switch . The operating mod e of the Α Sweep Generator cir- attenuation, and balance controls . Α trigger-pickoff stage in cuit is controlled by th e Α SWEEP MODE switch . In the the Channel 1 Vertical Preamp circuit supplies α sam ple of AUTO T R IG position, the absence of an adeq uate trigger the C hannel 1 signal to the Trigger Preamp circuit or the signal causes the sweep to free run . In the NO RM T R IG CH 1 O UT connector . The C hannel 2 Vertical P reamp position, α horizontal sweep is presented only when cor- circuit contains an invert feature to invert the Channel 2 rectly triggered by an adequate trigger signal . The SI NG LE signal as displayed on the C RT . The output of both Vertical SWEEP position allows o ne (and only one) sweep to be Pream p circuits is connected to the Vertical Switch ing initiated after the circu it is reset with the RESET button . circuit . Th is circu it selects th e channel(s) to be displayed . The Α Swee p Generator circuit also produces an unblanking An output signal from th is circuit is connected to the Ζ gate signal to unblan k the C RT so the display can be pre-

signal is coi n cid ent with the sawtoot h calibration of the instrument and the compensation of produced by th e Α Sweep Generator circuit . Α gate signal, probes . The PR OBE LOOP provides an accurate current wh ich is also coincid ent wit h th e sawtoot h , is available at source for calibration of current-measuring probe systems . the Α GATE connector on the side panel . T he Α Sweep Generator circuit also prod uces an alternate sync pulse, wh ich is connected to the Vertical Switch ing circuit . Th is CI RC U IT OPERATIO N pulse switch es the d isplay between ch annels at th e end of each sweep when the MOD E switch is in the A LT position . General The Β Sweep Generator circuit is basically the same as the Α Swee p Generator circuit . H owever, th is circuit only prod uces α sawtooth output signal after α delay time deter- mined by the Α ΤΙΜΕ/DIV switch and the DELAY-TIME MULTIPL I ER d ial . If the Β SWEEP MODE switch is set to the Β STA RTS A FT ER DELAY TIME position, the Β Sweep Generator begins to produce the sweep immed iately following the selected delay time . If th is switch is i n the TR IGG E RABLE A F TER DELAY TIME position, the Β Sweep Generator circuit does not prod uce α sweep until it receives α trigger pulse from the Β Trigger Generator circuit after the selected d elay time . The output of eit h er the Α or Β Sweep Generator circuit is amplified by the H orizontal Amplifier circuit to produce h orizontal d eflection for the C RT in all positions of the HO R IZ DISPLAY switch except Χ-Y . Th is circuit contains α 10 times magnifier to increase the swee p rate ten times in any Α or Β ΤΙΜΕ/DI V switch position . Other horizontal deflection signals can be connected to the H orizontal Amplifier by using the Χ -Υ mode of operation . When the Β SOUR CE switch is set to ΙΝΤ , the Χ signal is connected to the Horizontal Amplifier circuit through the CH 1 Vertical Preamp circuit, the Trigger Pream p circuit and the Β Trigger Generator circuit (HO R IZ DISPLAY switch set to Χ-Y, Β SOURCE switch set to ΙΝΤ , and the ΙΝΤ T R IG switch set to CH 1 O R Χ-Y) . In the ΕΧΤ or ΕΧΤ = 10 position of the Β SO UR CE switch , the Χ signal is obtained from α signal connected to the Β ΕΧΤ T R IG OR Χ I NPU T connector . Circuit Description-453Α/ R453A Th is section provides α detailed descri ption of the elec- trical operation and relationsh ip of the circuits in th e 453Α . The theory of operation for circuits uniq ue to th is instru- ment is described in detail i n th is d iscussion . Circu its w h ich are commonly used i n the electronics ind ustry are not d escribe d in d etail . If more information is desired on these commonly used circuits, refer to th e following textbooks : Tektronix Circuit Concepts Books (order from your local Tektronix F ield Office or representative) . Cat hod e- R ay Tubes, Te k tronix P art No . 062-0852-01 . Horizontal Am plifier Circuits, Tektronix Part No . 062-1144-00 . Oscillosco pe Trigger Circuits, Tektronix Part No . 062- 1056-00 . Power Supp ly Circuits, Tektronix Part No . 062- 0888-01 . Sweep Generator Circuits, Tektron ix Part No . 062- 1098-01 . Vertical Am plifier Circuits, Tek tronix Part No . 062- 1145-00 . Ph illip Cutler, "Semiconductor Circuit Analysis", McGraw-H ill, New York , 1964 . The Ζ Axis Amp lifier circuit determines the CR T inten- L loyd Ρ . H u nter (Ed .), " Handbook of Semiconductor sity and blank ing . The Ζ Axis Am plifier circuit sums the E lectronics", second edition, McGraw-H ill, New York , current in puts from the I N TENSITY control, Vertical 1962 . Switch ing circuit (chopped blank ing), Α and Β Sweep Gen- erator circuits (unblank ing), and the external Ζ AXIS Jacob M illman and H erbert Taub, "Pulse, Digital, and I NPUT bind ing post . The output level of the Ζ Axis Am pli- Switching Waveforms", McGraw-H ill, N ew York , 1965 . fier circuit controls th e trace intensity through the C RT Circuit . The CR T Circuit provides the voltages and contains the controls necessary for operation of the cathode-ray T he following circuit analysis is written around the tube . detailed block d iagrams wh ich are given for each major cir- cuit . T hese detailed block d iagrams give the names of the individ ual stages within the ma jor circuits and show how The Power Su pply circuit provides the low-voltage they are connected together to form the major circuit . T he power necessary for operation of th is instrument . Th is block diagrams also show the in puts and outputs for each voltage is d istributed to all of the circuits in th is instrument circuit and the relations h i p of the front- panel controls to as shown by the Power Distrubution d iagram . The Calibra- the individ ual stages . Th e circuit d iagrams from wh ich the for circu it produces α square-wave out put with accurate detailed block diagrams are derived are shown in the Dia- am plitude and frequency wh ich can be used to check the grams section . 3-3

NOTE from passing to the amplifier . The G N D position opens the signal path and the in put to the amplifier is connected to Α // references to direction of current in this manual ground . Th is provides α ground reference without the need are in terms ofconventional current; i.e., from plus to to d iscon nect the applied signal from the CH 1 connector . minus. Resistor R2, connected across the input coupling switch, allows C1 to be precharged in the GND position so the trace remai n s on screen when switched to the AC position CHANNEL 1 VERTICA L PREAMP with α high DC level app lied . General Input signals for vertical deflection on the C RT can be connected to the CH 1 O R Χ connector . In the Χ -Υ mode of o peration , th is input signal provides the horizo ntal (X- axis) deflection (HO R IZ DISPLAY switch set to Χ-Y, Β SOURC E switch set to ΙΝΤ , and ΙΝΤ TR IG switch set to C H 1 O R Χ ) . The Channel 1 Vertical Pream p circuit pro- vides control of in put coupling, vertical deflection factor, balance, vertical position, and vertical gain . It also contains α stage to provide α sample of the Channel 1 i nput signal to the Trigger Preamp circuit to provide internal triggering from the Channel 1 sig nal only . F ig . 3-2 shows α detailed block diagram of the Channel 1 Vertical Preamp circuit . Α schematic of th is circuit is shown on d iagram 1 at the rear of th is manual . For the CH 1 VOLTS/DI V switch positions above 20 Input Cou pl i ng mV, the attenuators are switched into the circuit singly or in pairs to produce the vertical deflection factor indicated Input signals applied to the CH 1 O R Χ connector can be on th e front panel . These attenuators are frequency- AC-coupled , DC-coupled , or internally disconnected . When com pensated voltage dividers . For DC and low-frequency Input Coupling switch S1 is in the DC position, the input signals, they are primarily resistance d ividers and the volt- signal is coupled directly to the Input Atten uator stage . In age attenuation is determined by the resistance ratio in the the AC position, the input signal passes through capacitor circuit . The reactance of the ca pacitors in the circuit is so C1 . This capacitor prevents the DC com ponent of the signal high at low frequencies that their effect is negligible . How- 3-4 S5 Input Attenuator The effective overall Channel 1 d eflection factor of the 453Α is determined by the CH 1 VOLTS/DI V switch. In all positions of the CH 1 VO LTS/DI V switch above 20 mV, the basic deflection factor of the V ertical Deflection Sys- tem is 20 millivolts per division of C R T d eflection . To in- crease this basic deflection factor to the values indicated on the front panel, precision attenuators are switched into the circuit . In the 5 and 10 mV positions, input attenuation is not used. Instead , the gain of the Feedback Amplifier is changed to decrease the deflection factor (see Feedback Am plifier d iscussion ) . Fig . 3-2 . Channel 1 Vertical Preamp detailed block diagram . Ι ~rτ Channel 1 signal to R75 Amplifier Vertical VAR Q84, η94, Switching circuit

ever, at h igher frequencies, the reactance of the capacitors selected to provide th e same amplitude AC and DC signal at d ecreases and the attenuator becomes primarily α εαραε- the base of Q33. C24 couples high-freq uency i nformation itance voltage d ivider . to the junction of R25-R26, thereby reducing the load ing at the base of Q43. In add ition to provid ing constant attenuation at all fre- quencies with in the bandwidth of the instrument, the Input Feedback Amplifier Attenuators are designed to maintain the same in put RC characteristics (one megohm Χ 20 p F) for each setting of Feedback Amplifier Q34 and Q54 changes the overall the CH 1 VO LTS/DI V switch . Each attenuator contains an gain of the Channel 1 Vertical P ream p to provide the cor- adj ustable series capacitor to provide correct attenuation at rect deflection factor in the 5 and 10 mV positions of the hig h-freq uencies and an ad j ustable shunt ca pacitor to pro- CH 1 VO LTS/DI V switch . Gain of th is stage is determined vide correct input capacitance . by the ratio of R46- R 50 to R 43, R 44, or R45 . In the 5 mV position of the CH 1 VO LTS/DI V switch , the network C43A-C43 B -C43C-C43D-C43 E -L 43A-R43A- R 43C-R 43E is In put Stage connected into the emitter circuit of Q34. The ratio be- tween R46-R50 and R43 provides α gain of about 10 . The Channel 1 signal from the In put Attenuator is con- C43A, C43C, L 43A, and R43C are adjustable to provide nected to th e Input Stage through the network C17-C18- hig h -freq uency peaking for the network . In the 10 mV posi- C20- R 16- R 17-R 18- R 19- R 20-R 21 . R 16, R 17, and R20 pro- tion, conditions are th e same except that the networ k vide the input resistance for this stage. These resistors are C44A-C44B-C44C-L 44A-R44A-R 44B -R 44C is connected part of the attenuation network at all CH 1 V O LTS/DIV into the circuit in place of the previous network . The ratio switch positions. Variable capacitor C17 ad j usts the basic between R 46-1350 and R44 provides α gain of about five input time constant for α nominal value of one megohm Χ times in this CH 1 V OLTS/DIV switch position . C44C 20 picofarads . The divider action of R16- R 17-R 20 allows and R 44C p rovid e h ig h fre q uency pea k ing for this about 98%ο of DC and low-frequency signals to pass to the network . In the 20 mV and h igher C H 1 VO LTS/DI V gate of FET (field-effect transistor) Q23A . C18, with the switch positions, the gain of the Feedback Amp lifier is stray capacitance in the circuit, forms an AC divid er which about 2.5 as estab lished by the ratio between R 46-R 50 and maintains th is same voltage division for high-freq uency sig- R45 . Ad j ustable ca pacitor C45A p rovides h igh-frequency nals . R18 limits the current d rive to the gate of Q23A . peaking for the Feedback Amplifier stage. C49 and R49 Diode C R 18 protects the circuit by clamping the gate of provid e h igh-frequency damping for the circuit . As men- Q23A at about -12 .5 volts if α h igh -amplitud e negative tioned previously, th e STEP ΑΤΤΕΝ BA L ad justment is set signal is a pplied to the CH 1 O R Χ connector . Over-voltage to provide zero volts at th e emitter of Q34when the input protection for h igh -am plitud e positive signals is provid ed by is at zero volts. Since there is no voltage difference across forward conduction of Q23A . Th is current path is th rough emitter resistor R43, R44, or R45, changing the value of R 23, L23, C R 36, and CR 37 . the resistance d oes not change the current in the circuit . T h erefore, the trace position will not change when switch ing between the 5 mV , 10 mV , and 20 mV positions of the CH 1 VO LTS/DI V switch if the ST EP ΑΤΤΕΝ BA L FET Q23B is α constant current source for Q23A and control is correctly ad justed . also provides tem perature compensation for Q23A . ST EP ΑΤΤΕΝ BAL ad j ustment R30 varies the gate level of Q23B to provid e α zero-volt level at th e emitter of Q34 with no signal a pplied . With α zero-volt level at the emitter of Q34, V ertical position of the trace is determined by the the trace position will not change w hen switch ing between setting of POSITIO N co ntrol R40 . This control changes the the 5, 10, and 20 mV positions of the CH 1 VO LTS/DI V current into the emitter of Q34, α low-impedance point, switch . whic h results in negligible voltage change at th is point . However, the change in current from the POSITION con- trol prod uces α resultant DC voltage at the output of the DC and low-frequency signals are connected from the F eedback Amp lifier stage to change the vertical position of source of Q23A to the Feed back Amplifier th rough R 23, the trace. C H 1 Position Center adjustment R55 is adjusted L23, Q33, and R39 . L23 isolates the base of Q33 from the to provid e α centered display when the Channel 1 POSI source of FET Q23A . Diodes C R 34-CR 35 and CR 36-C R37 ΤΙΟΝ control is centered (with α zero-volt DC input level) . limit the d ynamic range of the signal at the base of Q33 and prevent th e following stages from being damaged by α large voltage swing at the source of Q23A . T he signal path for Zener diode VR53 provides α low-impedance current hig h -freq uency signals is through C23, Q43, and C39. H ig h - source for Q54. Variable capacitor C54 provid es feedback freq uency signals at the emitter of Q43 are connected to from the collector to th e base of Q54 for amplifier stab ili- the base of Q33 through C38 . Th is allows Q33 to be d riven zation . The output signal from the F eedback Amp lifier at h igh frequencies wh ile preventing the base circuitry of stage is connected to the Para phase Amplifier stage and the Q33 from capacitively loading the input FET, Q23A . C38 is Channel 1 Trigger Pickoff stage. 3-5

Channel 1 Trigger P ίckoff Q84 and Q94 are connected as α common-emitter phase The signal at the collector of Q54 in the Feedback inverter (paraphase amplifier) to convert the single-end ed Amplifier stage is connected to the Channel 1 Trigger Pick- In put signal to α push-pull output signal . Gai n of this stage off stage through C R58 and R59. This sam ple of the is determined by the emitter degeneration . As the resistance Channel 1 input signal provides internal triggering from the between the emitters of Q84 and Q94 increases, emitter Channel 1 signal or X-axis deflection for Χ-Υ operation. degeneratio n increases also to result in less gain through the Q63 is connected as an emitter follower to provide isolation stage. GAIN ad justment R90 varies the resistance between the emitters to control the overall gai n of the Ch annel 1 between the Trigger Preamp circuit and the Feedback Am- Vertical P rea plifier stage . It also provides α minimum load for the Feed- back Amplifier stage and α low output imped ance to the Trigger Preamp circuit . CR58 provides thermal compensa- CHANNEL 2 VERTICAL PREAMP tion for Q63. CH 1 Trigger DC Level adj ustment R60 sets the DC level at the base of Q63 for α zero-volt DC output General level from the Trigger Preamp circuit when the Channel 1 The Channel 2 Vertical Preamp circuit is basically the trace is centered vertically . Output from the Channel 1 same as the Channel 1 Vertical Pream p circuit. Only the Trigger Pickoff stage is connected to the Trigger Preamp differences between the two circuits are described here . circuit through ΙΝΤ T R IG switch S230B . Portions of this circuit not described in the following description o perate in the same man ner as for the Channel , 1 Vertical Pream p circuit (corresponding circuit numbers Paraphase Amplifier assigned in the 100-199 range) . F ig . 3-3 shows α detailed The output signal from the Feedback Amplifier stage is block diagram of the Channel 2 Vertical Pream p circuit . Α connected to the Paraphase Amplifier stage th rough VAR schematic of this circuit is shown on diagram 3 at the rear (variable) control R75. When the VAR control is set to the of this manual . cali brated position (fully clockwise), R75 is effectively by-passed and maximum signal current reaches the base of Feedback Amplifier Q84 . Switch S75, ganged with the VAR control, is open and the UN CAL neon bulb is disconnected . As the VAR Basically, the Channel 2 Feedback Amplifier operates as control is rotated counterclockwise from the calibrated described for Channel 1 . However, the Channel 2 Vertical d etent, S75 is closed and UNCAL light DS75 ignites to Pream p circuit does not have α trigger pickoff stage . To ind icate that the vertical deflection factor is uncalibrated . provide α load at the collector of Q154 similar to the load The signal applied to the base of Q84 is continuously re- the Channel 1 Trigger P ickoff stage provid es at the collector duced as the VAR control is rotated counterclockwise . of Q54, C159 and R159 are co nnected into the circuit . 3-6 S105 Fig . 3-3. Channel 2 Vertical Preamp detaile d block diagram. ι ι ι Channel 2 1 Signal Το Vertical Switch ing Circuit ι ι ι ι

Am p lifier . CR 201 through C R 204 control the Channel 1 The basic C hann el 2 Paraphase Amp lifier configuration output and CR 206 through CR209 control the Channel 2 and operation is the same as for C h annel 1 . However, IN- output . These d iodes are in turn controlled by the VERT switch S195 has been add ed in the C hannel 2 circuit . Switch ing Multivibrator for dual-trace displays, or by the Th is switch allows the d isplayed signal from C hannel 2 to MOD E switch for single-trace displays . be inverted . VERTICAL SWITCH I NG volts is app lied to the junction of C R 207-CR 208 in the C hannel 2 Diode Gate through R 227 (see simplified d ia General gram in F ig . 3-5) . Th is forward biases C R 207-C R 208 and Th e Vertical Switch ing circuit determines if the CH 1 reverse biases CR 206-C R209, since the input to th e Delay- and/or the CH 2 Vertical Preamp output signal is connected L ine Driver stage is at about -5 .8 volts . C R 206-C R 209 to the Vertical Output Amp lifier circuit (through the Delay block the Channel 2 signal so it cannot pass to th e Delay- L ine Driver and Delay L ine stages) . In the ALT and C HOP L ine Driver stage . At the same time, in the Channel 1 Diode positions of the MOD E switch , both channels are alter- Gate, CR202-C R203 are connected to ground through nately displayed on α shared-time basis . F ig . 3-4 shows α 8212 . C R 202-C R203 are held reverse biased w h ile detailed b lock diagram of the Vertical Switching circuit . Α C R201-C R 204 are forward biased . Therefore, the C hannel schematic of th is circuit is shown on d iagram 5 at the rear 1 signal passes to the Delay-L ine Driver stage . of th is manual . CH 2 . In the CH 2 position of the MODE switch , the above cond itions are reversed . C R 202-C R203 are connected Diode Gates to -12 volts th roug h R 217 and C R 207-C R208 are con nec- ted to ground through R222 . The Channel 1 Diode Gate The Diod e Gates, consisting of four diod es each , can be blocks th e signal and the C hannel 2 Diode Gate allows it to thought of as switches wh ich allow either of the Vertical pass . Channel l signal from Channel l Vertical Preamp Channel 2 sign al from Channel 2 Vertical Preamp Alternate trace sy nc pu lse from 0 01 Α Sweep Ge nerator CH 1 . In the CH 1 position of the MODE switch , -12 F ig . 3-4 . Vertical Switching detailed bloc k diagram . Circuit Description-453Α/ R453A N ormal Trigger Pickoff Network Normal 0- (composite) trigger sign al to Trigger Preamp Delay- Vertical L ine Driver signal to Q24, Delay Q294 Line Chopped blan k ing to Ζ Axis Amplifier 3-7

Chan nel 1 Ver tical Preamp Signal in from Chann el 2 Vertical Preamp 3-8 R212 R222 *ΟCR202 CR201 R217 Ζ Ζ R211 R221 Ζ Ζ R227 \ S230A -12 ν \_ - - MnnF 1-- _ _ -/ -12 ν CR206 VCR207 Chann el 1 Diode Gate Signal path Reverse-biased diode To Delay-L ine Driver F ig . 3-5 . Effect of Diode Gates on sign al path (simplified Ve rtical Switch ing diagram) . Co nditions shown for CH 1 position of MOD E switch . Switch i ng MUIt iV i brdtor Q234 is off and holds the emitter of Q215 more negative than the emitter of Q225 . Wh en both Q215 and Q225 were ALT . In th is mode of operation , the Switching M ulti- off the voltage at their bases became approximately equal . vibrator operates as α bistable multivibrator . In the A LT Now when Q234 comes back on, the transistor with the position of the MOD E switch , -12 volts is app lied to the most negative emitter will start conducting first wit h the emitter of Alternate Trace Switch ing Am plifier stage Q234 resulting negative movement at its collector holding the by the MOD E switch . Q234 is forward b iased to su pply other transistor off . The conditions described previously are current to the "on" Switch ing-Μυltivibrator transistor reversed ; now the Ch annel 1 Diode Gate is reversed biased through R 234, and C R218 or CR 228 . For examp le if and the Ch annel 2 signal passes through the Chann el 2 Q225 is cond ucting, current is su pp lied to Q225 through Dio de Gate . R 228 . The current flow th rough collector resistors R221 and R 222 d rops the C R207-C R208 cathode level negative so the Channel 2 Diode Gate is blocked as for Channel 1 Reference F eedback stage Q253 provides common-mode only operation . The signal passes through the Channel 1 voltage feedback from the Delay-Line Driver stage to allow Diode Gate to the Delay-L ine Driver stage . the diode gates to be switched with α minimum amplitude switch ing signal . The emitter level of Q253 is co n nected to the junction of the Switching Mu ltivibrator collector resis The alternate-trace sync pulse is applied to Q234 tors, R211- R 212 and R221- R222 through CR213 or at the end of each sweep. Th is negative-going sync pulse CR223 . The collector level of the "on" Switch i ng Multi- momentarily interrupts the current through Q234 and both vibrator transistor is negative and either CR 213 or C R223 is Q215 and Q225 are turned off. When Q234 turns on again forward biased . Th is clamps the cathod e level of the after the alternate-trace sync pulse, the ch arge on C218 forward-biased shunt d iodes in the applicable Diode Gate determi n es whether Q215 or Q225 conducts . For example, about 0 .5 volt more negative than the emitter level of wh en Q225 was conducting, C218 was charged negatively Q253 . The level at the emitter of Q253 follows the average on th e C R 218 side to the emitter level of Q215 and voltage level at the emitters of the Delay-L ine Driver stage . positively on the CR 228 side . T h is charge is stored while The sh unt d iodes are clamped near their switching level and

-12 volts app lied to their cathodes th rough R 260 and am p litude switch ing signal . This maintains about the same R270. Since both signals are applied to the Delay-Line current th rough th e Diode Gate shunt d iodes so they can be Driver stage, the output signal is the algebraic sum of the switched with α minimum amplitud e switch ing signal, signals on both Channel 1 and 2 . regard less of the d eflection signal at the anodes of the shunt diodes . CHOP. In the CH O P position of the MODE switch, the Switch ing M ultivibrator free runs as an astable multi- vibrator at about α 500-kH z rate . The emitters of Q215 and Q225 are connected to -12 volts through R 218 and R228 . At the time of turn-on, one of the transistors begins to cond uct ; for example, Q225 . Q225 conducts the C hannel 2 current and prevents the Channel 2 signal from reach ing the Delay-L ine Driver stage . M eanwhile, th e Channel 1 Diode Gate passes the Channel 1 signal to the Delay-Line Driver . Delay-Line Driver Circuit Description-453Α/R 453A Output of the Diod e Gate stage is applied to Delay-Line Driver stage Q284 and Q294 . Q284 and Q294 are con- nected as operational amplifiers with feed back provided by R268-13269 and R278- R279 and the delay-line compensa- tion network . The delay-line compensation network , C261- C262-C263-C264-C265-C266-R261-R262-R264- R 265, pro- vides h ig h-frequency com pensation for the Delay Line . R289-C289 in the collector circuit of Q284-Q294 im prove the h ig h -frequency reverse termination of the Delay L ine . Output of the Delay-L ine Driver stage is connected to the Vertical Output Amplifier th rough the Delay L ine . The frequency-determining components in the CHOP mod e are C218-R218-R228 . Switching action occurs as follows : When Q225 is on, C218 attem pts to charge to -12 Normal Trigger Pic koff Network volts through R 218 . The emitter of Q215 slowly goes The toward -12 volts as C218 charges . The base of Q215 is held trigger signal for NO RM trigger operation is obtained from the collector of Q284 . Normal Trigger DC at α negative point determined by voltage divid er Level adj ustment R285 sets the DC level of the normal R215-R224 between -12 volts and the collector of Q225 . trigger output signal so the sweep is triggered at the zero- When the emitter voltage of Q215 reaches α level slightly level of the d isplayed signal when the Triggering LEVEL more negative than its base, Q215 conducts . The collector control is set to 0 . The normal trigger signal is connected to level of Q215 goes negative and pulls the base of Q225 the Trigger Pream p through S230B . R294 and R295 pro- negative also, through divider R214-R225, to cut Q225 off vide the same DC load for allow Q215 to conduct . This action switches the Diode r as provided to Q284 by Gate stage to connect the opposite half to the Delay-Line the Normal Trigger Pickoff Network . Driver stage . Again C218 begins to charge towards -12 volts but this time th rough 8228 . The emitter of Q225 VERTICAL OUTPUT AMPL I F I ER slowly goes negative as C218 charges, until Q225 turns on . Q215 shuts off and the cycle begins again. General The Vertical Output Am plifier circuit provides the final Diodes CR218 a nd C R228 have no effect in the CHO P amplification for the vertical deflection signal . This circuit mode . Q253 operates the same in CHOP as in ALT, to includes the Delay L ine and the BEAM F I N D ER switch . allow the Diode Gates to be switched with α minimum The BEAM F I ND ER switch compresses an overscanned d is signal level . play with in the viewing area when pressed in . F ig . 3-6 shows α detailed block d iagram of the Vertical Output Am plifier circuit . Α schematic of this circuit is shown on Th e Cho pped Blank ing Amplifier stage, Q244, provides d iagram 6 at the rear of th is manual . an output pulse to the Ζ Axis Amplifier wh ich blanks out the transition between the Channel 1 trace and the Chann el 2 trace . When the Switching M ultivibrator changes states, Delay Line the current through Τ241 momentarily changes . Α negative Delay Line DL301 provides approximately 140 ηαηο - pulse is applied to the base of Q244, to tu rn it off . The seconds delay for the vertical signal to allow the Sweep width of the pulse at the base of Q244 is determined by Generator circuits time to initiate α sweep before the verti- R241 and C241 . Q244 clips the signal applied to its base, cal signal reaches the vertical deflection plates . This allows and the positive-going outpu t pulse, wh ich is coincident the instrument to display the lead ing edge of the signal with trace switch ing, is app lied to the Ζ Axis Amp lifier originating the trigger pulse w hen using internal triggering . circuit through R245 . ADD . In the ADD position of the MODE switch, the Phase Equalizer Network Diode Gate stage allows both signals to pass to the Delay- The Phase Equalizer N etwork is com prised of L 301- Line Driver stage . The Diode Gates are both held on by 1_302-1-311-C301-C302-C311-C312 . This network compen- 3-9

Vertical deflection signal to vertical deflection plates sates for the phase distortion of the Delay Line . C303-13303 when large signals deflect the display off screen . Τ357 pro- and C313-13313 in series with the base-emitter resistance of vides high-frequency balance for the Output Amplifier Q304 and Q314 provide the forward termination for the stage . Q364 and Q374 provide the output signal voltage to Delay L ine . drive the C RT vertical d eflection plates . LR 367 and LR377 provid e damping for the leads connecting the output signal to the deflection plates . Q304 and Q314 are connected as common-base amp li- TR IGG ER PREAMP fiers to provide α low input impedance to properly ter- minate the Delay L ine (along wit h the Phase Equalizer Net- General work ) . It also provides isolation between the Delay L ine and the following stages . The Trigger Preamp circuit amplifies the internal trigger signal to the level necessary to d rive the Α and Β Trigger Generator circuits . Input signal for the Trigger P reamp cir cuit is either α sam ple of th e signal app lied to Channel 1 or The output of Q304 and Q314 is connected to the bases α sample of the composite vertical signal from the Vertical of 0324 and Q334 . Th e network C326-C327-C328-C336- Switching circuit . F ig . 3-7 shows α detailed b lock diagram R328 provides h igh-freq uency peak ing to com pensate for of the Trigger Pream p circuit . Α schematic of th is circuit is th e capacitive loading of the d eflection plates on the output shown on diagram 7 at the rear of th is manual . stage . C328, C336, and R328 are adj ustable to provide opti- mu m response . BEAM F I NDER switch S330 red uces the quiescent current of Q324 and Ο334, when pressed , to compress an off-screen d isplay wit h in the graticule area . N ormally, th e collector current for Q324 and Q334 is Input C ircu itry su pp lied th roug h R 321, R322 and th e parallel combination The internal trigger signal from the Vertical Deflection of R323 a nd R333 . When S330 is pressed , -12-volts is System is connected to the Trigger Preamp through ΙΝΤ connected to the collector circuit of Q324 and Q334 T R IG switch S230 B . When the ΙΝΤ T R IG switch is in the th roug h R 332 . Th is reduces the collector potential of Ο324 NO RM position, the trigger signal is α sample of the com- and Q334 to limit their dynamic range and compress the posite vertical signal in the Vertical Switching circuit . Th is display vertically wit h in the graticule area . Although th is signal is obtained from the collector of Q284 and is α compressed d isplay is nonlinear, it provides α method of sample of the d isplayed channel (or channels for d ual-trace locating α signal th at is off screen vertically d ue to incorrect o peration) . Since the signal source follows the dual-trace positioning or deflection factor, switch i ng stage, the N O RM trigger signal also includes the chopped switch ing transients when o perating in the C HOP mode . When the ΙΝΤ T R IG switch is in the N ORM Ο344 and Q354 am plify the output of Q324 and Q334 . position, the C H 1 lights DS400 and DS401 are d iscon- The sig nal at the collectors of 0344 and Ο354 is app lied to nected . Also, the sample of the Channel 1 signal is con- t he out p ut tran sistors, Q364 and Q374, th rough nected to th e C H 1 OU T connector . Th is output signal can C344- R 344-VR 344, C354- R 354-VR 354, and Τ357 . VR 344 be used to monitor C hannel 1 or it can be used to cascade and VR 354 prevent saturation of Q344 and Q354 to im- with Channel 2 to provide α one millivolt/d ivision minimum prove the recovery of the Vertical Output Amplifier circuit deflection factor (with reduced bandwidth ) . 3-1 0

Preamp F rom Q284, Vertical Switch ing S230B ΙΝΤ T R IG Ι Ι Ι Ι Ι Ι Ι Ι Ι Ι DS400 DS401 Ι ι Ι N ORM CΗ 1 ςΗ 1 (Α Triggeri ng) Ι (Β Triggering) F ig . 3-7 . Trigge r Preamp detailed block diagram . Circuit Description-453Α/R453A Internal trigger signal to Α Trigger Ge nerator Internal trigger sign al to Β Trigger Generato r In the CH 1 OR Χ -Υ position of the ΙΝΤ TR IG switch , converts the trigger voltage signal at its base to α current the internal trigger signal is obtained from the emitter of d rive for the remainder of the Trigger Preamp . C R408 in Q63 in the CH 1 Vertical Preamp circuit . Now, the internal the emitter circuit of Q404 provides thermal compensation trigger signal is α sample of only th e signal app lied to the for th e am plifier . CH 1 OR Χ connector . The CH 1 lights are turned on to ind icate that the ΙΝΤ T R IG switch is in the CH 1 O R Χ -Υ position and the CH 1 OU T connector is discon nected from T he signal current at the collector of Q404 is connected the circuit . to the base of Q414 . Q413, Q414, and Q423 are connected as α curren t-driven, voltage-output operational amplifier . R402, R 403, and R404 terminate the coaxial cables The amp lified signal at the collector of Q414 is connected from the trigger pickoff stages to provide α constant load d irectly to the base of Q413, and to the base of Q423 for these stages . In th e NORM position of the ΙΝΤ TR IG through zener diod e VR 421 . Th is zener diode provides α switc h , the N O RM trigger signal from the Vertical DC voltage drop wh ile the signal is connected to the base of Switc h ing circuit is terminated at the in put to the amp lifier Q423 with minimum attenuation . 0413 and Q423 are con- by R404 . The C H 1 O R Χ -Υ trigger signal from the C H 1 nected as emitter followers in th e com plementary sym- Vertical Pream p circu h is terminated at the C H 1 OU T metry am plifier configuration . Th is configuration over- connector by R402 . I n the CH 1 O R Χ -Υ position, the CH comes th e basic limitation of emitter followers ; inability to 1 O R Χ -Υ trigger signal is terminated at the input to the provide eq ual response to both positive- and negative-going amp lifier by R 404, and the NO RM trigger signal is termina- portions of α signal . Th is is remedied in th is configuration ted by R 403 . by using an ΝΡΝ transistor for one emitter follower, 0413, and α ΡΝΡ transistor for the other emitter follower, Q423 . Since Q413 is an ΝΡΝ transistor, it responds best to Amplifier Circuitry positive-going signals and Q423, being α ΡΝΡ transistor responds best to negative-going signals . The result is α cir- The internal trigger signal selected by the ΙΝΤ T R IG cuit which has eq ually fast response to both positive- and switch is connected to the base of Q404 . Transistor Q404 negative-going trigger signals wh ile maintaining α low out- 3- 1 1

Preamp circuit is connected to the base of Q414 th rough R 419. This feedback provides more linear operation . Total overall gain of the Trigger Preamp is about 10 . The amp li- fied internal trigger signal is connected to the Α and Β SOUR CE switches through R 427 and R429 . General Α TRIGGER G ENERATOR The Α Trigger Generator circuit produces trigger pulses to start the Α Sweep Generator circuit . These trigger pulses are derived either from the internal trigger signal from the Vertical Deflection System, an external signal connected to the ΕΧΤ TR IG I NPUT connector, or α sample of the line voltage applied to the instrument . Controls are provided in th is circuit to select trigger level, slope, cou pling, and source . Fig. 3-8 shows α d etailed block diagram of the Α Trigger Generator circuit . Α schematic of th is circuit is shown on diagram 8 at the rear of th is manual . S430 SOURCE Α Trigger Ι signal ΙΝΤ 1 C435 AC Ι from Trigge r Preamp L INE C436 LF ρ ,R EJ *__--0 Line trigger signal from Power Supply ΕΧΤ __Q ΕΧΤ - 10 3-1 2 S435 I Trigge r Τ D CR475 Input Stage 0443,Q453 R460 ο DC ιενει ?F~ S455 Fig . 3-8. Α Trigger Generator detailed block diagram . line, and external . Α fourth position of the Α SOUR CE switch provid es 10 times attenuation for the external trig- ger signal . The internal trigger sign al is obtained from the Vertical Deflection System th rough the Trigger Preamp circuit . Th is signal is α samp le of the signal(s) applied to the CH 1 OR Χ and/or CH 2 OR Υ connectors . Further selection of the internal trigger source is provide d by the ΙΝΤ TR IG switch to provide the internal trigger signal from both channels or from Channel 1 only (see Trigger Preamp d iscussion for details) . The line trigger is obtained from voltage divid er R 1104- R1105 in the Power Su pply circuit . This sample of the line frequency, about 1 .5 volts RM S, is cou pled to the Α Trigger Generator in the L I NE position of the Α SOUR CE switch. The Α COUPLI NG switch should not be in the LF REJ position when using this trigger source . Trigger Source External trigger signals applied to the Α ΕΧΤ T R IG I NPUT connector can be used to produce α trigger in the The Α SOURCE switch, S430, selects the source of the ΕΧΤ and ΕΧΤ - 10 positions of the Α SOURCE switch. Α trigger signal . Three trigger sources are available; internal, In put resistance (DC) is about one megohm in both exter- Slope Comparator 0454, 0464 -ON Pulse - Shaper Q484 Pulse Amp lifier 0473 Auto Mu ltivibrator 0485, 42494, Q495 Trigger pulse to Α Sweep Gen erator Auto gate to Α Sweep Generator ι ι ι ι ι ι ι ι ι ι ι ι

the LF REJ position of the Α wh ich the sweep is triggered . The reference voltage for the COUPL I NG switch , th e med ium and h igh -frequency resis- comparator is provided by Α LEVEL control R460 a nd Α tance d rops to about 90 kilohms due to the add ition of Trigger Level Center adjustment R462 . The Α Trigger Level C436-R436 in the circuit . In the ΕΧΤ - 10 position, α 10 Center ad justment sets the level at the base of Q464 so the times frequency compensated attenuator is connected into d isplay is triggered at the zero-volt DC level of the incoming the in put circuit . This attenuator reduces the input signal trigger signal when the Α LEVEL control is centered . The Α am plitude 10 times to provide more Α LEVEL control LEVEL control varies the base level of Q464 to select the range while maintaining the one-megohm Χ20 pF i nput RC point on the trigger signal where triggeri ng occurs . characteristics. Trigger Coupling The Α COUPL I NG switch offers α means of accepting or rejecting certain frequency components of the trigger sig- nal. In the AC and LF REJ positions, the DC component of the trigger signal is blocked by cou pling capacitors C435 or C436 . In the AC position , frequency components below about 30 hertz are attenuated . In the LF REJ position, frequency components below about 30 k ilohertz are atten- uated . The HF REJ position attenuates high-frequency com- ponents of the triggering signal . The trigger signal is AC cou pled to the in put, attenuating signals below about 30 hertz and above about 50 kilohertz . The DC position pro- vid es eq ual cou pling for all signals from DC to 60 mega- hertz . Input Stage T he trigger signal from the Α COUPL I NG switch is con- nected to the Input Stage th rough the network C440-R 438- R439-R440-R 441 . R438-R439 provide the in put resistance for th is stage . The voltage-d ivider action of R438-R439 allows about 98% of DC or low freq uency signals applied to R438 to be available at the junction of R438 and R439 . C440 along with the stray capacitance in the circuit forms an AC divider wh ich maintains about th is same voltage divi- sion for h igh -freq uency signals. R440 limits the current d rive to the gate of FET Q443 . Diode CR441 protects the circuit by clamping the gate of Q443 at about -12 .5 volts if α h igh -am plitude negative signal is applied to the ΕΧΤ TR IG INPUT connector. Over-voltage protection for high- amplitude positive signals is provided by the forward con- duction of FET Q443 . Q443 is connected as α source follower to provide α high input impedance and α low output imped ance . As α result, this stage provid es isolation between the Α Trigger Genera- tor circuit and the trigger signal source . The output signal ' from Q443 is connected to the Slope Com parator stage through emitter follower Q453 . Diode CR 449, CR459, and The slope of the input sign al wh ich triggers the Α sweep VR460 provide protection for the Slope Comparator stage is determined by Α SLOPE switch S455 . When the Α transistors, Q454 and Q464 . S LOPE switch is set to the - position, the collector of Q454 is connected to the +12-volt su pply through CR456 Slope Comparator and R 467 . The anode of CR466 is ground ed and it is re-' verse biased . Now the collector current of Q464 must flow Q454 and Q464 are connected as α difference amp lifier through CR 465, R459, the parallel combination CR475 (com parator) to provide selection of the slope and level at and R 468-R 469-L469, and R467 to the +12-volt supply Circuit Description-453Α/R453A R458 establishes the emitter current of Q454 and Q464 . The transistor with the most positive base controls conduc- tion of the comparator . For example, assume that the trig- ger signal from the Input Stage is positive going and Q454 is forward biased . The increased cu rrent flow through R458 produces α larger voltage drop, and the emitters of both Q454 and Q464 go more positive . Α more positive voltage at the emitter of Q464 reverse biases this transistor, since its base is held at the voltage set by the Α LEVEL control, and its collector current decreases . At the same time, Q454 is forward b iased and its collector current increases . N otice that the signal currents at the collectors of Q454 and Q464 are opposite in phase. The sweep can be triggered from either the negative-going or positive-going slope of the input trigger signal by producing the trigger pulse from either the signal at the collector of Q464 for - slo pe operation or the signal at the collector of Q454 for + slope operation. Th is selection is made by SLOPE switch S455 . When the Α LEVEL control is set to 0 (midrange), the base of Q464 is at about one volt positive, which corres- ponds to α zero-volt level at the input to this circuit (with correct calibration) . The base-emitter drop of Q464 sets the common emitter level of Q454-Q464 to about +ρ.3 volt . Since the base of Q454 must be about 0 .65 volt more posi- tive than the emitter before it can cond uct, the com parator switches arou nd the zero-volt level of the trigger signal (zero-volt level on the trigger signal correspond s to about one volt positive at th is point) . As the Α LEVEL control is turned clockwise toward +, the voltage at the base of Q464 becomes more positive . Th is increases the current flow through R 458 to produce α more positive voltage on the emitters of both Q454 and Q464 . Now the trigger signal must rise more positive before Q454 is biased on . The re- sulta nt CRT disp lay starts at α more positive point on the displayed signal . When the Α LEVEL control is in the - region, the effect is the opposite, to produce α resultant CRT d isplay which starts at α more negative point on the trigger signal . 3-13

(see Fig . 3-9) . Since the output pulse from the Α Trigger operates in its low-voltage state . The current from one of Generator circuit is derived from th e negative-going portion the transistors in the Slope Comparator stage is diverted of the signal applied to the Trigger TD stage, the sweep is th rough th e Trigger TD stage by th e Α SLOPE switch . As triggered on the negative-going portion of the input trigger th is current increases due to α change in the trigger signal, signal (signal applied to Trigger TD stage is in phase with tunnel d iode C R475 switches to its h igh -voltage state . L 469 th e in put signal for - slope triggering) . When the Α SLOPE opposes th e sudd en change in current, wh ich allows more switch is set to +, cond itions are reversed (see F ig . 3-10) . current to pass through CR475 and switch it more quick ly . Q464 is connected to the +12-volt supp ly throug h C R 466 As the current flow stab ilizes, L469 again conducts the and R 467 . The anode of C R456 is grounded to divert the major part of th e current . However, the current th rough collector current of Q454 through the Trigger TD stage . CR 475 remains h igh enough to hold it in its high-voltage The signal a pplied to the Trigger TO stage is now 180 ° out state . The circuit remains in th is cond ition until the current of phase with the input trigger signal, so the sweep is trig- from the Slo pe Com parator stage decreases due to α change gered on the positive-going portion of the in put signal . in the trigger signal app lied to the input . Then, the current through C R 475 decreases and it reverts to its low-voltage state . Trigger TD T he Trigger TO stage shapes the output of th e Slope Pulse Am pl if ier Comparator to provide α trigger pulse with α fast lead ing The trigger signal from the Trigger TO stage is connected edge . Tunnel d iode CR 475 is q uiescently biased so it to th e base of Pulse Amplifier Q473 through R 472 . The 3- 1 4 ο CR456 Q ά S455 - SLQPE - - -Ι R467 C467 R473 Ι Ι C466 CR455 CR465 δ* CR466 -12 V R453 +12 V C473 R468 ~ ~CR475 R471 -0 ΤΡ475 R469 ρ L469 R459 Ι R472 Q473 Av\A/-- I : 5 ~.Υ Current path Reverse-biased d iode +75 V Fig . 3-9 . Trigger path for negative-slope triggering (simplified Α Trigger Generator diagram) .

+ρ.5 volt . Α simultaneous negative-going pulse with the wit h α fast rise . The width of the pulse d epends upon the same wid th as the trigger pulse is available at the emitter of waveshape of the input signal and th e setting of the Α 0473 . Th is pulse is connected to the Auto Pulse Amp lifier L EVEL control . Q473 is connected as an amplifier with the stage . primary of pulse transformer Τ474 provid ing the major col- lector load . The negative-going pulse at the base of Q473 Auto Pulse Amplifier d rives it into heavy cond uction and the resulting current increase of Q473 flows through Τ474, R474, Q473, C473, The negative-going trigger pulse from the emitter of and C467 . Due to the short time constant of the RC net- Q473 is connected to the base of Q484 through R481 . Th is work involving C473, the current of Q473 quick ly returns stage is similar to the Pulse Amplifier stage . Ind uctor L484 to the level determined by 8473 . The resultant signal at the provid es the collector load for this stage . The positive-going collector of Q473 is α positive-going fast-rise pulse with the portion of the trigger pulse is cou pled to the Auto M ulti- width determined by th e time constants of th e RC network vibrator stage th rough C R484 . C R483 clamps the collector in the circuit . Τ474 inverts the output pulse to produce α of Q484 at about -0.5 volt to eliminate negative transients . negative-going trigger pulse wh ich is coincident with the rise of the output signal from the Trigger TD stage . Th is Auto M ultivibrator negative-going trigger pulse is connected to the Α Sweep Generator circuit through C476-R 476 . C R 474 limits the T he basic configuration of the Auto M ultivibrator stage collector of Q473 from going more positive than about is α monostable multivibrator made up of Q485 and Q495 . CR455 CR465 -12 V R453 CR456 _V* Ι \,/ C R466 +12 V R471 R459 R469 ~ ~ ι469 R472 Cu rrent path Reverse-biased d iode Circuit Description-453A/ R453A +7ς V R473 0473 F ig . 3-10 . Trigger path for p ositive-slope triggerin g (simp lified Α Trigger Gen erator diagram) . 3- 1 5

Trigger Generator circuit . Operation in the AUTO TR IG circuits located in the Α Sweep Generator circuit . Under position is much the same as NORM T R IG except that α quiescent cond itions (no trigger signal), the base of Q495 is free-runn ing trace is displayed when α trigger pulse is not near zero volts. The base of Q485 is held at about -0.65 present . In the SI NGLE SWEEP position, operation is also volt by the forward voltage drop of CR484 . Since the base similar to NORM TR IG except that the sweep is not re- of Q495 is the most positive, it cond ucts and raises the, current . The following circuit description is given with the emitter level of Q485 positive enough to hold it off. C485 Α SWEEP MODE switch set to NORM TR IG . Difference in charges to about +13 volts where it is clamped by CR486 operation for the other two modes are then discussed later. and CR493. The base of Q494 is clamped at about +12.6 volts by CR493, which reverse biases it . Since there is no current flow th rough Q494, its collector level goes negative . Normal Trigger Mode Operation When α trigger signal is present, the positive-going pulses from the Auto Pulse Am plifier stage turn Q485 on th rough C R484. The collector of Q485 goes negative and C485 d is- charges rapid ly th rough Q485, R490, and R485 . As C485 d ischarges, the current flow through R490 b iases Q495 off. When C485 is fully discharged , the current flow th rough R490 ceases and Q495 comes back on to reset the multi- vibrator . Now C485 begins to charge towards +75 volts through R486. Current also flows through R494, and the base of Q494 goes negative to bias it on . The collector level of Q494 rises positive to produce the auto gate output for the Α Sweep Generator circuit . Sweep Gate . The negative-going trigger pulse generated by the Α Trigger Generator circuit is applied to th e Sweep Gate stage through C R501 . Tunnel diode CR505 is quies- cently biased on in its low-voltage state. When the negative- going trigger pulse is applied to its cathode, the current through CR505 increases and it rap idly switches to its high- voltage state, where it remains until reset by the Sweep Reset M ultivibrator stage at the end of the sweep . The negative-going level at the cathode of CR505 is connected to the base of Q504 through C503 and R503 . Q504 is turned on and its collector goes positive . This positive-going step is connected to the Disconnect Diod e through C509-R509 and to the Output Sig nal Amplifier through C506-R506 . For low-frequency signals (below about 30 hertz), C485 rech arges to about +13 volts in about 85 milliseconds . Output Signal Amplifier . The positive-going gate pulse Then, Q494 is biased off to end the auto gate (display free from the Sweep Gate stage applied to the base of Q514 ru n s or is unstable) . However, if α repetitive trigger signal turns produces α negative-going pulse at its collector . This pulse is Q485 on again before C485 has charged to +13 volts, C485 connected to th e Ζ Axis Am plifier circuit through R519 to is d ischarged completely again and once more starts to unblan k the CRT du ring sweep time . It is also connected to charge towards +75 volts. Si nce the base of Q494 remains the H oldoff Capacitor through R 517 and CR517 to dis- negative enough with α repetitive trigger signal to hold it in charge it com pletely at the beginning of each sweep . conduction, the auto output level is continuous for α stable display (with correct Α LEVEL control setting) . The positive-going gate pulse at the base of Q514 is also coupled from the emitter of Q514 to the emitter of Q524 . Α SWEEP G ENER ATOR The resulting positive-going signal at th e collector of Q524 is coupled to the Vertical Switching circuit through C526 General to provide an alternate-trace sync pulse for dual-trace operation . It is also coupled to the Α GATE output con- The Α Sweep Generator circuit prod uces α sawtooth nectoron the side panel through R529 . C R 528 and C R529 voltage which is amp lified by the Horizontal Amplifier cir- clamp the gate signal so it does not go more than about 0 .5 cuit to provide horizontal sweep deflection on the CRT. volt negative and 12 .5 volts positive . This output signal is generated on comman d (trigger pulse) from the Α Trigger Generator circuit . The Α Sweep Gen- erator circuit also produces an unblanking gate to unblank the CRT during the Α sweep time . I n addition, this circuit produces several control signals for other circuits within Disconnect Diode . Disconnect Diode C R 533 is quies- this instrument and several output signals to the side-panel cently conducting current th rough R 506, R508, R509, connectors . Fig . 3-11 shows α detailed block diagram of the R530, and R531 . This prevents timing current from Timing Α Sweep Generator circuit . Α schematic of th is circuit is Resistor R530 from charging Timing Capacitor C530 . The shown on diagram 9 at the rear of th is manual . positive-going gate signal from Q504 reverse b iases CR533 and interru pts the qu iescent current flow . Now the timing current through the Timing Resistor begins to charge Timing Capacitor C530 so the Sawtooth Sweep Generator The Α SWEEP MODE switch allows three modes of stage can produce α sawtooth output signal . The positive- operation. In the NORM TR IG position, α sweep is pro- going gate signal also reverse biases CR547 to disconnect duced only when α trigger pulse is received from the Α the Sweep Start Amp lifier . Th e Disconnect Diode is α fast

from Α Trigge r Generator Fig. 3-11 . Α Swee p Ge nerator detailed block diagram . Circuit Description-453Α/R453A Sawtoot h Sweep Generato r 0533, 0531 S530A Α sweep to Delay-P ic koff Comparator Β Sweep Generator --}"~ Α sweep to Horizontal Amplifier Α unblan k ing gate Alternate trace sy nc pu lse Α GATE turn-off d iode with low reverse leakage to red uce switching Q533 through R533 . Th is produces α positive-goi ng output time and improve timing linearity at the start of the sweep. voltage which is connected to the base of Q531 through R536 . Q531 am plifies and inverts the voltage change at its base to produce α negative-going Sawtoot h output . To pro- Sawtoot h Sweep Generator . The basic generator circuit vide α linear charging rate for the Timing Capacitor, the is α M iller Integrator circuit . Wh en the current flow through sweep output signal is connected to the negative side of C R533 is interru pted by the Sweep Gate signal, the Timing C530 . Th is feedback provides α constant charging current Capacitor C530 begi ns to charge through Timing Resistor for C530 wh ich maintains α constant charge rate to prod uce R 530, and the Α Sweep Cal Adjustment R 531 . The Timing α linear Sawtoot h output signal . The output voltage con- Capacitor and R esistor are selected by the Α ΤΙΜΕ/DI V tinues to go negative un til the circuit is reset through the switch to change sweep rate . The Α Sweep Cal adj ustment Sweep R eset Multivibrator stage . The output signal from allows calibration for accurate sweep timing . The Α VA R the collector of Q531 is connected to the H orizontal control, R530Y (see Timing Switch diagram), provides vari- Amplifier circuit through R538, the Delay Pickoff Com- able swee p rates by varying the charge rate of the Timing parator stage i n the Β Sweep Generator circuit th roug h Capacitor . UNCA L light DS530W (see Diagram 12) ind i- R 532, and the Β Sweep Start stage th roug h the H OR I- cates when the sweep is not calibrated . ZO NTA L DISPLAY switch . The positive-going voltage at the R530 side of C530 as it Sweep Reset E mitter Follower . The negative-goi ng saw- charges toward +75 volts is connected to the gate of FET tooth voltage at the collector of Q531 is connected to the 3- 1 7

stage is turned on to rapidly d ischarge the Timing Capacitor negative-going signal at the emitter of Q543 is coupled to and pull the gate of Q533 rapidly negative to its o riginal the Sweep Reset Multivibrator stage to determine sweep level to produce the retrace portion of the Sawtooth signal . length and to the Sweep Start Amplifier stage to set the The Sawtooth Sweep Generator stage is now ready to pro- starting point for the sweep. C R542 connected to the base duce another sweep as soon as the Sweep R eset Mu lti- of Q543 protects th is stage du ring instrument warmup. vibrator stage is reset and another trigger pulse is received . Sweep Start Amplifier . The signal at the emitter of Q543 When Q575 is turned on to end the sweep, it remains in goes negative along with the applied Sawtooth signal . Th is cond uction for α period of time to estab lish α holdoff increases the forward bias on CR 543, which in turn de- period and allow all circuits to return to their original con- creases the forward bias on CR 545 as the Sawtooth goes ditions before the next sweep is produced . The holdoff negative . When the a node of C R543 reaches α level about time is determi ned by the charge rate of Holdoff Capacitor o ne volt more negative than the level on the base of Q544, ς550 . At the start of the sweep , C550 is completely dis- it is reverse biased to interru pt the current flow through charged by the unbla nk ing gate at the collector of Q514 . It Q544 . is held at th is level throughout the sweep time . When the Sweep Gate output end s, Q514 is cut off and C550 begins The circu it remains in th is condition until after the to charge toward +75 volts through R 552 and R551 . The sweep retrace is complete . As the voltage at the emitter of positive-going voltage across the H oldoff Capacitor as it Q543 returns to its original DC level at the end of the charges is connected to the base of Q575 through CR552 sweep , C R545 is again forward biased and Q544 cond ucts and VR 559 . When the base of Q575 rises positive enough through CR547 to set the quiescent current through the so it is reverse biased , its collector level drops negative and Disconnect Diode CR533 . T h is establishes the correct Q585 comes back into conduction . The bias on the Sweep starting point for the sweep . CR 546 clam ps the collector of Gate tun nel diode CR505 retu rns to α level that allows it to Q544 at about +0 .5 volt . This reduces the voltage swing at accept the next trigger pulse (C R505 is enabled) . Holdoff the collector of Q544 and improves the response time . Capacitor C550 is changed by the Α ΤΙΜΕ/DIV switch fo r Sweep Start ad j ustment R758 (in the Β Sweep Generator the various sweep rates to provide the correct holdoff time . circuit) sets the base voltage level of Q544 . The collector of Diagram 12 shows α complete diagram of the Α ΤΙΜΕ/DIV Q531 is held at this same voltage level through the feedback etch . loop comprised of Q533 and Q531, thereby setting the starting point of the Sawtooth output signal . The level established by the Sweep Start ad justment is also connected As the Α SWEEP LENGTH control is rotated counter- to the Β Sweep Start Am plifier so the Β sweep starts at the clockwise from the FULL position , R555 places α more same voltage level as the Α sweep (except i n MIXED) . positive level on the anode of C R556 than is on the anode of C R 555 so C R555 remains reverse biased . The Sweep Reset M ultivibrator is reset as described for FULL sweep Sweep Reset Multivibrator . The negative-goi ng Sawtooth length operation at the point where C R556 (instead of signal at the emitter of Q543 is coupled to the cathodes of CR555) is forward b iased. Since th is occurs at α more posi- CR555 and CR 556 . These diodes are quiescently reverse tive level on the negative-going Sawtooth, the displayed biased at the start of the sweep . As the Sawtooth voltage at sweep is shorter. Thus, R555 provides α variable sweep its cathode goes negative, C R555 is forward biased at α level length for the Α sweep (from about 11 d ivisions in the about 0.5 volt more negative than the base level of Q575 (Α FULL position to about four d ivision s in the fully clock- SWEEP LENGTH control in FULL position) . Then the wise position-not in Β EN DS Α detent) . In the Β ENDS Α negative-going Sawtooth signal from the Sweep Reset position (fully counterclockwise), α negative-going pulse Emitter Follower stage is connected to the base of Q575 . from the Β Sweep Generator circuit is connected to the Q575 and Q585 are connected as α Schmitt bistable multi- base of Q575 through CR 575 at the end of the Β sweep vibrator . Quiescently, at the start of the sweep, Q585 is time . If the Α sweep is still runni ng, this negative-going conducting and Q575 is biased off to produce α negative pulse turns Q575 on to end the Α sweep also . Since the Α level at its collector . This negative level allows Sweep Gate sweep ends immed iately following the end of the Β sweep, tunnel d iode C R 505 to be switched to produce α sweep as t h is position provides the maximu m repetition rate discussed previously . When the negative-going sweep signal (brightest trace) for Delayed Sweep mode operation . is connected to the base of Q575 through C R 555, Q575 is eventually biased on and Q585 is biased off by the emitter cou pling between Q575 and Q585 . The collector of Q575 rises positive and CR505 is switched back to its low-voltage The HF STA B control, R551, varies the charging rate of state through R502 . CR 505 is held in its low-voltage state the Holdoff Capacitor to provide α stable disp lay at fast so it cannot accept incoming trigger pulses until after the sweep rates . Th is change in holdoff allows sweep synchro- Sweep Reset M ultivibrator stage is reset . This end s the nization for less d isplay jitter at the faster sweep rates . The Sweep Gate stage output and the Disconnect Amplifier HF STAB control has little effect at slow sweep rates . 3- 1 8

through C R555 or C R556 at the end of the sweep . With vibrator stage in the Α Trigger Generator circuit is con- Q575 on, C R505 is held in its low-voltage state to lock out nected to Lam p Driver stage Q594, throug h CR 591 and any incoming trigger pulses . The circuit remains in th is εοη - C R 594 . Th is gate level is coincident wit h the trigger pulse dition until reset by the Single-Sweep Reset Amp lifier generated by the Α Trigger Generator circuit and is present stage . only when th e instrument is correctly triggered . T he positive-going auto-gate level saturates Q594 and its col- lector goes negative to about zero volts . Th is applies about Single-Sweep Reset Amplifier . Single-Sweep Reset 12 volts across DS596, Α SWEEP TR IG'D ligh t, and it Amp lifier Q564 prod uces α pulse to reset the Sweep Reset comes on . Th is light remains on as long as the auto-gate Multivibrator stage so anot her sweep can be prod uced in level is present . When the auto-gate level goes negative be- the SI NG LE SWEEP mode of operation . Quiescently, Q564 cause the instrument is no longer triggered , CR 595 clam ps is biased off and th e RES ET switch is open . When the the base level of Q594 at about -0 .5 volt and Q594 is RES ET button is pressed, DS568 ignites and th e voltage at reverse biased . The collector of Q594 rises positive and the base of Q564 goes negative . Q564 saturates and pro DS596 goes off . duces α positive-going output pulse . Th is pulse has suffi- cient amplitude to shut off Q575 and allow Q585 to con- duct and enable Sweep Gate tunnel d iode C R505 . Now the Auto Trigger Mode Operation Α Sweep Generator circuit can be triggered when the next O peration of the Α Sweep Generator circuit in the trigger pulse is received . AUTO TR IG position of the Α SWEEP M OD E switch is the same as for the NO RM T R IG position j ust described when α Lamp Driver . In the SI NG LE SWEEP mode, the cathode trigger pulse is app lied. H owever, when α trigger pulse is not of CR 591 is connected to ground to b lock the incoming present, α free-running reference trace is produced in the auto-gate level . Α SWEEP T R IG'D ligh t DS596 is discon AUTO TR IG mode . Th is occurs as follows : nected from the collector of Q594 and RES ET light DS597 is connected into th e circuit . The anode of C R 595 is also d isconnected from ground . Now the cond ition of Q594 is The auto-gate level from the Auto M ultivibrator stage in determined by th e Sweep Reset Mbltivibrator stage . When the Α Trigger Generator circuit is also connected to CR592 . Q585 is off before the RESE T button is pressed , the col- When the auto-gate level is positive (instrument triggered), lector level of Q585 is negative . The current th rough the current flowing through CR592 and R593 reverse biases R594-CR595-R587- R 588 sets the base level of Q594 nega- CR593 and Sweep Gate tunnel d iode C R505 operates as tive enough to bias it off . H owever, when the RESET previously d escribed for NORM TR IG operation . H owever, button is pressed and Q585 turns on, its collector goes when the instrument is not triggered , the auto-gate level positive . Th is positive level allows the base of Q594 to go d ro ps negative and the reduction in current through C R592 positive also and it is biased on . The collector of Q594 goes and R593 allows C R593 to become forward biased . Now, negative and the RESE T lig ht comes on . Q594 and the when the Sweep Reset M ultivibrator stage resets at the end RESET light remain on until Q585 turns off again at the of th e hold off period, the add itional current from end of the next sweep. R593-C R 593 flows th rough CR505 and is sufficient to automatically switch th e Sweep Gate tunnel diod e back into its h igh -voltage state . Th e result is that the Α Sweep Β TR IGG ER G ENERATO R Generator circuit is automatically retriggered at the end of each h oldoff period and α free-running sweep is produced . Since the sweep free runs at the sweep rate of the Α Sweep General Generator circuit (as selected by the Α ΤΙΜΕ/DI V switch ), The Β Trigger Generator circuit is basically the same as α brig ht reference trace is prod uced even at fast sweep rates . the Α Trigger Generator circuit . Only the d ifferences be- tween the two circuits are discussed here . Portions of the circuit not described in the following discussion operate in Single Sweep Operation the same manner as for the Α Trigger Generator circuit General . O peration of the Sweep Generator in the (correspond ing circuit nu mbers are assigned in the 600-699 range) . F ig . 3-12 shows α detailed block diagram of the Β SI NG LE SWEEP position of the Α SWEEP MODE switch is Trigger Generator circuit . Α schematic of th is circuit is similar to operation in the other modes . However, after one shown on d iagram 10 at the rear of th is ma n ual . sweep has been produced , the Sweep Reset Multivibrator stage does not reset . All succeed ing trigger pulses are locked out until the RESET button is pressed . Input Stage The Β Input Stage operates in basically the same manner In the SI N G LE SWEEP position, the Α SWEEP M OD E as described for the Α Trigger Generator circuit . H owever, switch d isconnects the charging current for the Holdoff in the Β Trigger Generator circuit, HO R IZ DIS PL AY switch Capacitor . Now, Q575 remains on when it is forward biased S801A and C R 638 block the Β Trigger Generator input 3- 1 9

3-20 ΕΧΤ TR IG OR Χ L ine trigger sign al from ΕΧΤ Power Supply L INE - Ο S635 113 SWEEP M Ι S801Α Ι HOR IZ DISPLAY Ι ι Ι COUPL ING 5610 Ι ΙΙ SOUR CE Ι Ι Ι Ι Ι Β trigger Ι Ι sign al Ί Ι ~ from Trigger ΙΝΤ Ι C615 AC Ι Inp ut Slope Preamp 0-0ν Ο633 ι Stage Comparator Οβςq, Οβ64 ο643 +10 Attenuator Trigger Trigger Pulse pulse TO Amp lifier to Β S615 Ι Ι Ι CR675 Ο684 Sweep Generator R660 E xter n al I NPUT ΙL-~ Ho rizo n tal Gain Network F ig . 3-12 . Β Trigger Ge nerator detailed block diagram . External horizontal signal to Horizontal Amplifier signal in the modes where Β triggering is not desired . In the connected to its cathode th roug h R 642 by S801A . The Α position of the HO R IZ DISPLAY switch , -12 volts is signal from the Input Stage is connected to the Horizontal connected to the cathode of C R 635 and it is forward Amplifier th rough C R 641 and External Horizontal Gain biased . Since the cathode of C R638 is connected to +12 Network R 644-R645-R646 . Gain of the External H ori- volts throug h R 638, C R 638 is reverse b iased and it blocks zontal circuit is set by R 645, E xt H oriz Gain, so α signal the trigger signal . In the Α ΙΝΤΕΝ D UR I NG Β , Β app lied to the CH 1 O R Χ connector produces the indi (DELAYE D SWEEP), and M IX E D positions, α second cated horizontal deflection . switch , Β SWEEP MOD E S635 determines whether the Β trigger signal is blocked or passed to the Slope Comparator stage . If the Β SWEEP M OD E switch is in the Β STA RTS A FT ER DELAY TIME position, th e trigger signal is bloc ked as in the Α position . However, the Β Sweep Gen- The external horizontal signal can be obtained either erator essentially free ru ns in th is position as controlled by externally from the Β ΕΧΤ TR IG O R Χ I N PU T connector another portion of the Β SWEEP M OD E switch located in when the Β SOUR CE switch is set to ΕΧΤ or ΕΧΤ = 10, or the Β Sweep Gen erator circuit (see Β Sweep Generator d is- internally from Channel 1 when the ΙΝΤ T R IG switch is in cussion ) . In the TR IGG ERABLE A FT ER DELAY TIME the CH 1 OR Χ -Υ position and the Β SOUR CE switch is set position, -12 volts is connected to the cathode of CR 638 to ΙΝΤ . through R639 rather than to C R635 . Th is forward biases C R638 and allows the Β trigger signal to pass to the Β Slope Comparator stage . Pulse Amplifier S655 S LOPE In all positions of the HO R IZ DISPLAY switch except The Pulse Am plifier i n the Β Trigger Generator operates Χ-Y, C R 641 is bac k biased since it is connected to +12 much the same as in the Α Trigger Generator . H owever, volts through R 641 . In the Χ -Υ position, C R638 is reverse since there is no Auto circuit in the Β Trigger Generator, α biased because its cathode rises positive toward +12 volts pulse is available only at the collector of Q684 . The output applied through R 638 . Therefore, the trigger sig nal can not pulse is a pplied to the Β Sweep Generator through Τ686 pass th roug h C R 638 . C R 641 is forward b iased by -12 volts and R 688-C688 .

is the same as The Β Swee p Generator circuit is basically the same as the corresponding circuit in the Α Sweep Generator circuit . the Α Swee p Generator circu it . Only the differences be- Two unblan king gates are available from the collector of tween the two circuits are d iscussed here . The following 0714 . An unblank ing gate is connected to the Ζ Axis circuits operate as described for the Α Sweep Generator Am plifier circuit through R 717 and the HOR IZ DISPLAY (corres ponding circuit numbers assigned in the 700-799 switch to unblank the C R T to display the Β sweep . F or Α range) : Sweep Gate (C R 705, Q704), Disconnect Diode ΙΝΤΕΝ DUR I N G Β operation, add ition al unblanking (C R 742), Sawtoot h Sweep Generator (0743 and Q741), current is added to the Α unblan k ing gate during the Β and the Sweep Reset Emitter Follower (Q753) . F ig . 3-13 sweep time . Th is produces α display which is partially υη - shows α detailed block diagram of the Β Sweep Generator b lanked during Α sweep time and further unblanked during circuit . Α schematic of th is circuit is shown on diagram 11 Β sweep time to prod uce α display w h ich has an intensified at the rear of th is manual . portion coinciden t wit h the Β sweep time . Β SWEEP G ENER ATO R Output Signal Amplifier Circuit Description-453Α/R453A Mixed Sweep Unb lank ing Multivi brator 0779,Q790 Trigger pulse from Β Trigger Generator S635 F ig . 3-13 . Β Sweep Generator detailed bloc k diagram . Mixed Sweep Unb lank ing to Ζ-Axis Amplifier Β un blanking gate to Ζ Axis Amplifier Α intensified un blanking gate to Ζ Axis Amplifier 3-2 1

Β E nds Α Pulse Amplifier pulse forces the Β Sweep Reset Multivibrator to reset and The positive-going voltage as the Β unblanking gate end s end th e Β sweep also . is cou pled to Β Ends Α Pulse Amplifier Q734 through C731 and C R731 . When the Α SWEEP LEN GTH control is in the Delay Multivibrator Β EN DS Α position, th is pulse saturates Q734 to produce α negative-going output pulse at its collector . Th is negative- The Delay M ultivibrator, Q768 and Q772, provides α going pulse is connected to the Α Sweep Reset Multivibra- lockout for the Β Sweep Generator circuit during the Α for stage to reset the Α sweep at the end of the Β sweep for Sweep Generator reset and holdoff time to allow accurate maximum delayed sweep repetition rate . delayed-sweep measurements w hen the DELAY-TIME MULTI PL I ER dial is set near 0 . Th is stage prevents the Β Sweep Generator from being triggered before the Α Sweep Delay-Pickoff Comparator Generator is triggered ( Β Sweep Generator must always be The Delay-Pick off Comparator stage allows selection of triggered after the Α Sweep Generator is triggered) . Th is th e amount of d elay from the start of the Α sweep before circuit also produces α pulse wh ich resets the Β Sweep the Β Sweep Generator is turned on . Th is stage allows the Reset M ultivibrator stage after the delay period so the Β start of Β sweep to be delayed between 0.20 and 10 .20 Sweep Gate tunnel d iode can be enabled to produce α times the setting of the Α ΤΙΜΕ/DI V switch . Then, the Β sweep. Sweep Generator is turned on and o perates at α sweep rate independent of the Α Sweep Generator (determined by Transistors 0768 and Q772 are connected as α Schmitt setting of Β ΤΙΜΕ/DI V switch ) . bistable multivibrator . Quiescently, Q772 is held on by the negative level at th e collector of Q764A and Q768 remains Q764A and Β are connected as α voltage comparator . In off . The circuit remains in th is cond ition until the incoming th is configuration, the transistor with the most positive ρ` sweep switches the Delay-Pickoff Comparator (see Delay- base controls conduction . Α dual transistor, Q764, and α Pickoff Comparator discussion) . Then, the base of Q772 dual d iode, C R764, provide tem perature stability for the goes positive and it turns off . At the same time, the base of com parator circuit . Q769 maintains α constant current Q768 is pulled negative by the collector level of Q764B and th rough the conducting transistor . Reference voltage for it turns on . Th e collector of Q772 goes negative and α negative-going output pulse is cou pled to the Β Sweep the comparator circuit is provid ed by DELAY-TIME Reset M ultivibrator stage through C774 . Th is pulse resets MULTI PL I ER control R760 . The voltage to th is control is the Β Sweep Reset M ultivibrator wh ich in turn enables the filtered by R759-C759 to hold it constant and allow precise Β Sweep Gate stage . delay pickoff . The instrument is calibrated so that the ma j or dial mark ings of R760 correspond to the ma j or divi- sions of horizontal deflection on the graticule . For M ixed Sweep if the DELAY-TIME MULTI PL I ER d ial is set to weep Unblan k ίng MuIt~V ίbrator 5.00, the Β Sweep Generator is delayed five d ivisions of the Transistors Q779 and Q790 com prise α bistable multi- Α sweep time before it can prod uce α sweep ( Β sweep delay vibrator very similar in configuration to the Sweep Reset time equals five times setting of Α ΤΙΜΕ/DI V switch ) . Multivibrator . The purpose of the Mixed Sweep Unblank ing Multivibrator is to provide add itional unblanking d uring the Β sweep portion of α mixed sweep display . Because the Β The output sawtoot h from the Α Sawtoot h Sweep Gen- Sweep Generator is normally running at α faster sweep rate erator stage is connected to the base of Q764A . The quies- than the Α Sweep Generator in α mixed sweep d isplay, th is cent level of the Α sawtoot h biases Q764A on and its col- add itional unblanking reduces the intensity differences be lector is negative enough to hold Q772 in the Delay Multi- tween the two parts of the d isplay . vibrator stage in cond uction . As the Α sweep output saw- tooth begins to run down, the base of Q764A also goes negative . When it goes more negative than the level at the base of Q764B (established by the DELAY-TIME MULTI- During th e Α Sweep portion of α mixed sweep display, PL I ER control), Q764B takes over conduction of the com- transistor Q779 is off and Q790 is on . At the end of the parator and Q764A shuts off . Th is also switches the Delay d elay time α negative pulse is coupled to the base of Q779 M ultivibrator stage to produce α negative-going reset pulse from the collector of Q772 by capacitor C774 . Q779 is to the Β Sweep Reset Multivibrator . turned on and its collector goes positive . Th is positive movement is coupled to the base of Q790 through C780-11780, and Q790 turns off . At the same time th at Q779 is turned on, the pulse from C774 turns Q775 on and When the Α sweep resets, Q764A is again returned to its collector goes positive . The negative movement of the conduction and Q764B is turned off . Th is also resets the collector of Q790 and the positive movement of the col- Delay M ultivibrator to prod uce α positive-going output lector of Q775 are added together so that the net change at pulse . If the Β sweep is still running, th is positive-going the base of Q797 is an app roximate 0.6 volt more positive 3-22

When the Β Sweep Reset Multivibrator is reset by the to ste p slightly more negative to further unblan k the C RT Delay Multivibrator, Q775 comes on and Q785 turns off . display . Then at the end of th e Β Sweep time, Q790 turn s The collector of Q785 goes negative and Β Sweep Gate on and Q775 turns off . The negative movement at the base tunnel diode CR 705 is enabled. The state in which C R705 of Q797 is sufficient to cause total blanking of the CRT so remains depends upon the Β SWEEP MODE switch and the any remaining part of Α Sweep is not seen . HOR IZ DIS PLAY switch . When Β SWEEP M ODE switch S635 is set to the T R IGGER ABLE AF TER D ELAY TIME position, C R705 is biased so it can be switched to its high - Mixed Sweep Unblanking Ampl if ier voltage state by the next trigger pulse from the Β Trigger In the MIX E D position of the HO R IZ DISPLAY switch , Generator . However, in the Β STARTS AF TER DELAY TIME position, the setting of HOR IZ DISPLAY switch +12 volts is applied to the collector of the M ixed Sweep Sg01A determines operation of the Β Sweep Gate tunnel Blank ing Amplifier Q797 through collector load resistor diod e . In the Α position, the Β trigger pulses are block ed in R797 . Th is activates Q797 so it can am plify the mixed- the Β Trigger Generator circuit so the Β Sweep Generator sweep unblanking gate at its base . The output at the εοΙ - cannot be triggered and does not prod uce α sweep. In the lector of Q797 is added to the Α unblanking gate (see Hori- remaining positions of S801A, -12 volts is connected to blanking zontal Display Switch , Diagram 14) to produ ce α composite the cathode of C R705 through R786 and R789 . Th is ng gate for the Ζ -Axis Amplifier . voltage pulls the cathode of CR 705 negative enough so it automatically switches to its h igh -voltage state after it is enabled by the Β Sweep Reset M ultivibrator stage . Th is Sweep Start Am plifier produces α free-ru nning Β sweep reset similar to the no In all positions of the HO R IZ DISPLAY switch except trigger AU TO T R IG mod e in the Α Sweep Generator, How- MIXED, the operation of Β Sweep Start Amplifier Q754 is ever, since the Β Sweep is reset (and automatically re- the same as described for the Α Sweep Start Amplifier triggered) at α fixed point on the Α sweep sawtooth , the stage . In the M IX E D position, the Sweep Start control d isp lay is relatively stable . The best delayed sweep stability R758 is disconnected from the base of Q754 and the Α is provided in the T R IGGER ABLE AF TER D ELAY TIME sweep sawtooth is app lied . Now, the point at which the Β position, since the Β sweep is triggered by the trigger signal Sweep Generator will start generating its sawtoot h wave- in th is mode . form is constantly being changed by the Α sweep sawtoot h . The outp ut waveform from the Β Sweep Generator takes the form of α composite sawtoot h waveform with the first and last parts occurring at α rate determined by the Α HO R IZO NTAL AMPL I F I ER Sweep Generator (last part of com posite sweep blanked out), and the middle part at α rate determined by the Β General Sweep Generator . T he Horizontal Amplifier circuit provides the output sig- nal to the C R T horizontal deflection plates . In all positions of the HO R IZ DISPLAY switch except Χ-Y, the horizontal deflection signal is α sawtooth from either th e Α Sweep Generator circuit or the Β Sweep Generator circuit . In the Sweep R eset Multivibrator Χ -Υ position , the horizontal deflection signal is obtained from the Input Stage of the Β Trigger Generator . In The basic Β Sweep Reset Multivibrator configuration addition, th is circuit contains the horizontal magnifier cir- and operation is the same as for the Α Sweep Generator . it and the horizontal positioning network . F ig . 3-14 However, several differe nces do exist . The Β Sweep Reset cu it α detailed block d iagram of the H orizontal Amp lifier Multivibrator does not have α sweep length network for circuit . Α schematic of th is circuit is shown on d iagram 13 variable sweep length or α Holdoff Capacitor and associated at the rear of th is manual . circuit to reset the Β Sweep Reset Multivibrator after the retrace . Instead, the negative-going sweep from the Β Sweep Reset E mitter Follower, 0753, is connected to the base of Input Amp lifiers Q785 through CR748 . Diode CR 748 is forward biased when the sweep voltage at the emitter of Q753 dro ps about The input signal for the Horizontal Am plifier is selected 0.5 volt more negative than the level at the base of Q785 by HO R IZ DISPLAY switch S801A . In the Α and Α estab lished by voltage d ivid er R784-R785 between +12 ΙΝΤΕΝ DUR I N G Β positions of the HO R IZ DISPLAY volts and the collector of Q775 . T h is negative-going saw- switch , the sawtooth from the Α Sweep Generator is con- tooth turns on Q785, and its collector goes positive to nected to the base of the - Input Amplifier, Q814, through switch Β Sweep Gate tunnel d iode C R705 to its low-voltage R803 . In the Β (D ELAY E D SWEEP) position, the Β saw- state, wh ich resets th e Β Sweep . Q785 remains on and holds tooth is connected to the base of 0814 and in the MIXED the Β Sweep Gate tunnel diode locked out until the Β position, the com posite sawtoot h from the Β Sweep Gen- Sweep Reset Multivibrator is reset by th e Delay Multi- erator is connected to the base of Q814 . Whichever saw- vi brator . tooth signal is connected to the base of Q814 prod uces α Circuit Description-453Α/R453A 3-23

mixed sawtooth from Β Sweep Ge nerator 3-24 Exter n al horizontal sig n al from Β Trigger Generator MAG Fig. 3-14 . Horizontal Amp lifier detailed bloc k diagram . S330 BEAM F INDER Horizontal deflection signal to horizon tal deflectio n plates current change wh ich is amplified to prod uce α positive- Q814 . These controls vary the q uiescent DC level at the going sawtooth voltage at the collector . Th is positive-going base of Q814 wh ich in turn sets the DC level at the horizon- sawtooth signal is connected to the base of Q834 in the tal deflection plates to determine th e horizontal position of Para ph ase Amplifier stage . the trace . C804-13804 eliminate common-mode noise from the position controls . In the Χ -Υ positio n of the HO R IZ DISPLAY switch , the external horizontal signal from the Β Trigger Generator cir- Paraphase Amp l if ier cuit is connected to the base of the + Input Amplifier, Q824, th rough R 821 . The Α and Β sawtoot h signals are The output of the + and - Input Amplifier stages is grounded by the HO R IZ DISPLAY switch . The Β SOURC E connected to Paraphase Amplifier Q834 and Q844 . Th is switch selects either the internal signal from Ch annel 1 stage converts the single-ended input signal from either ( ΙΝΤ TR IG switch set to CH 1 O R Χ-Y) or an extern al Input Amplifier stage to α push-pull output signal wh ich is signal connected to the ΕΧΤ T R IG OR Χ I NPUT connec- necessary to drive the horizontal deflection p lates of the tor . When the internal signal is selected, the Chan nel 1 CRT . In all positions of the HO RIZ DISPLAY switch deflectio n factor as indicated by the CH 1 VO LTS/DI V except Χ-Y, α positive-going sawtooth signal is connected to switch applies as Horizontal V olts/Divisio n . M ore informa- the base of Q834 through Q814 . Th is produces α negative- tion on the external horizontal circuitry is contained in the going sawtooth voltage at the collector of Q834 . At the Β Trigger Generator circuit d iscussion . same time, the emitter of Q834 goes positive and th is change is connected to the emitter of Q844 through the gain-setting network , R835-13836-R845-13846 . In all posi- Horizontal positioning is provided by POSITIO N control tions of the HO R IZ DISPLAY switch except Χ-Y, no signal R805A, and F I NE control R 805B connected to the base of is connected to the base of Q844 through Q824 so Q844 Οί

Μαg Register adj ustment R855 balances the quiescent fier . T hen, the positive-going change at its emitter is ampli- DC current to the base of Q863 and Q873 so α center- fied to prod uce α positive-going sawtoot h signal at the screen d isplay does not change position when the MAG collector . T hus the single-ended in put sawtoot h signal has switch is changed from Χ 10 to O FF . been amplified and is available as α push-pull signal at the collectors of Q834 and Q844 . In the Χ -Υ position of the HO R IZ DISPLAY switch , the external horizontal deflection signal is connected to the base of Q844 through Q824 and the sawtoot h signal at the base of Q814 is disconnected . Now, the circuit operates much the same as j ust described for α sawtoot h input . Α positive-going external horizontal deflection signal produces α negative-going change at the base of Q844 wh ich de- creases the current flow th roug h th is transistor . The collector of Q844 goes positive wh ile the emitter-coup led signal to Q834 prod uces α negative-going change at the collector of Q834 . Th is stage also provides ad j ustment to set the normal General and magnified gain of the H orizontal Amp lifier circuit, and The Ζ Axis Amplifier circuit controls the C RT intensity the MAG switch to provide α horizontal sweep which is level from several in puts . The effect of these in put signals is magnified 10 times . For normal sweep operation ( MAG to either increase or decrease the trace intensity, or to com- switch set to OFF), R835 and R836 control the emitter level blank ρ γ portions of the d isplay . F ig . 3-15 shows α degeneration between Q834 and Q844 to set the gain of the detailed block diagram of the Ζ Axis Amplifier circuit . Α stage . R835, N ormal Gain, is adj usted to provide calibrated sc hematic of th is circuit is shown on diagram 15 at the rear sweep rates . Wh en M AG switch S801 B is set to the Χ 10 of th is manual . positio n , R845 and R846 are co n nected in parallel with R835 and R836 . Th is additional resistance decreases the emitter degeneration of th is stage to increase the gain of the Input Amplifier circuit 10 times . R845, M ag Gain, is ad justed to provide calibrated magnified sweep rates . When the MAG switch is The input transistor, Q1014, in the Input Am plifier set to Χ 10, MAG ON light DS849 is connected to the stage is α current-d riven, low-input im pedance am plifier . It +150-volt supp ly through R849 . DS849 ignites to ind icate provides termination for the input signals as well as iso- that the sweep is magn ified . In the Χ -Υ position of the lation between the input signals a nd the following stages . HO R IZ DISPLAY switch , the magn ifier is connected into The current signals from the various control sources are the circuit by S801A so the horizontal gain is correct for connected to the emitter of Q1014 and the sum o r d iffer- external horizontal operation regardless of the setting of ence of the signals determines the collector conduction the MAG switch . However, bot h sides of DS849 are con- level . C R 1015 and C R 1016 in the collector provide limiting nected to ground so it can not ignite . protection at minimum intensity . When the I NTENSITY control is set fully countercloc kwise (minimum), the col- Output Amplifier lector current of Q1014 is reduced and its collector rises positive . C R 1015 is reverse biased to block the control cur- The push-pull output of the Para ph ase Amplifier is con- rent at the base of Q1023, and C R 1016 is forward biased to nected to the Output Amplifier . Each half of the Output protect the circuit by clamping the collector of Q1014 Am plifier can be considered as α single-ended , feedback about 0.5 volt more positive than the emitter level of amp lifier wh ich amp lifies the signal current at its input to Q1023 . Th is limiting action also takes p lace when α prod uce α voltage output to drive the horizontal deflection blank ing signal is applied . The clamping of C R 1016 allows plates of the CRT . The amplifiers have α low i nput im- Q1014 to recover faster to prod uce α sharper d isplay with pedance and require very little voltage change at the input sudden changes in blan k ing level . At normal intensity levels, to p roduce t h e d esired output ch ange . Diod es CR 1016 is reverse biased and the signal from Q1014 is CR851-C R852 and CR 861-C R 871 protect the am plifier cou pled to emitter follower Q1023 th roug h C R 1015 . from being overdriven by excessive current swing at the collectors of Q834 and Q844 . N egative feedback is pro- vided from the collectors of the final transistors, Q884 and The input signals vary the current drive to the emitter of Q894, to the bases of the i nput transistors through 01014, wh ich produces α collector level that determines C882-13882 and C892-R 892 . C882 and C892 adjust the the brilliance of the display . I NTENSITY control R1005 transient response of the amp lifier so it has good li nearity sets the quiescent level at the emitter of Q1014 . When at fast sweep rates . R1005 is turned in the clockwise directio n , more current Circuit Description -453A/R 453A BEAM F I N D ER switch S330 red uces h orizontal scan by limiting the current available to Q884 and Q894 . Normally the collectors of these transistors are returned to +150 volts . However, when the BEAM F I N D ER switch is pressed in, the power from the unregulated +150-volt supply is interru pted and th e collector voltage for Q884 and Q894 is supplied from +75 volts th roug h CR884 . Since th e collec- tors are returned to α lower potential, the output voltage swing is reduced to limit the horizontal deflection with in th e graticule area . Ζ AXIS AMPL I F I ER 3-25

Vertical Chopped Blan king Sign al from Ve rtical Switch ing Circuit External B la r ιk ing R 1011 from Ζ AXIS I NPUT ------^V1V`V Connector Α and Β unblank ing gate from Sweep Ge ne rator circu its Input Ou tpu t Amplifier Amplifier INTENSITY Q1014, Q1023 Q1024,01034 R 1005 Q1043 / R 1004 R 1012 C1036 R 1036 Fig . 3-15. Ζ Axis Amplifier detailed block diagram . Unblank ing gate to CR T circuit from the I NT ENSITY control is added to the emitter cir- cou pled com plementary amp lifier . This configuration pro- cuit of Q1014, wh ich results in an increase in collector vides α linear, fast output signal with minimum q uiesce nt current to provide α brig hter trace . However, the vertical power . chopped blank ing, Ζ Axis Input, and sweep unblan king signals (Α , Β , and mixed ) determine whether the trace is visible . The vertical chopped blank ing signal blanks the trace during dual-trace switch ing . Th is signal decreases the The overall Ζ-Axis Amplifier circuit is α shunt-feedbac k current through Q1014 during the trace switch ing time to operational amp lifier with feedback from the Output blank the CRT d isplay . The external blank ing in put allows Am plifier stage to the Input Amp lifier stage through an external signal connected to the Ζ AXIS I NPUT con- C1036-C1037- R 1036 . The output voltage is determined by nector to change the trace intensity . Α positive-going signal the input current times the feedback resistor and is shown connected to the Ζ AXIS I NPUT connector decreases trace by the formula : Εουτ = ιιη Χ Rfb where Rfb is R1036 . The intensity and α negative-going signal increases trace inten- unblank ing input current change is approximately two sity . T he Α , Β , and mixed unblanking gate signals from the milliamperes . T herefore, the output voltage change is about Α and Β Sweep Generator circuits blank the CRT during 60 volts (2 mA Χ 30 .1 kΩ ) . C1036 adj usts the feedbac k sweep retrace and recovery time so there is no disp lay on circuit for optimum h igh-frequency response . the screen . When the Sweep Generator circuits are reset and recovered (see Α and Β Sweep Generator d iscussion for more information), the next trigger initiates the sweep and an unblanking gate signal is generated by the Α or Β Sweep Ζener d iode VR 1043 connected between +75 volts and Generator circuit that goes negative to allow the emitter +150 volts through C R 1044, R 1044, and R 1043 produces α current of Q1014 to reach the level establish ed by the +90-volt level at the cathode of VR 1043 . Th is voltage I NTEN SITY control and the other blank ing inputs . establishes the correct collector level for Q1043 . C R 1045 connected from base to emitter of Q1043 improves the response of Q1043 to negative-going signals . When the base Output Ampl if ier of Q1043 is driven negative to cutoff, C R 1045 is forward b iased and conducts the negative-going portion of the υη - The resultant signal produced from the various inputs by blank ing signal . T h is provides α fast falling edge on the the In put Amplifier stage is connected to the base of unb lank ing gate to quick ly turn the display off . The output Q1024 th rough C1029 and to the base of Q1034 th rough unblank ing gate at the emitter of Q1043 is connected to R 1024 . These transistors are connected as α collector- the C RT circuit th rough R 1046 . 3-26

later when C913 discharges sufficiently to raise the voltage at the base of Q930 positive enough to bias Q930 into General conduction again . The cycle repeats at α freq uency of 40 to 50 k ilohertz . The amplitud e of sustained oscillatio n T he C RT Circuit provides the high voltage and co ntrol depends upon the average current delivered to the base of circuits necessary for operation of the cathode-ray tube Q930 . (CRT) . F ig . 3-16 shows α detailed block diagram of the C RT Circuit . Α sc hematic of th is circuit is shown on d ia- gram 16 at the rear of th is manual . F use F 937 protects the +12-volt Supply if the High - voltage Oscillator stage is shorted . C937 and L937 prevent the current changes at the collector of Q390 from affecting High-Voltage Oscillator the+12-volt regulator circuit . Q930 and associated circuitry comprise the h igh -voltage oscillator to prod uce the drive for high-voltage transformer Τ930 . When the instrument is turned on, the current High-Voltage Regulator through R925 charges C913 positive and Q930 is forward F eedback from the secondary of Τ930 is connected to biased . The collector current of Q930 increases and α the base of Q914 through the voltage d ivider networ k voltage is developed across the collector windi ng of Τ930 . 8903-R910 . Th is sam ple of the output voltage is compared Th is prod uces α corresponding voltage increase i n the feed - to the -12-volt level at the emitter of Q914 . Any change i n back winding of Τ930 wh ich is con nected to the base of the level at the base of Q914 produces an error signal at the Q930, and it conducts even harder . Wh ile Q930 is on, its collector of Q914 wh ich is amplified by Q914 and Ο913 base current exceeds the current through R925 and C913 and applied to the base of Q923 . Amplitude of the oscilla- charges negatively . Eventually the rate of collector current tions at the collector of 0930 is determined by the average increase in Q930 becomes less than that required to main- DC level at the emitter of Q923 . tain the voltage across the collector winding, and the out- put voltage d rops . Th is turns off Q930 by way of the feed- back voltage to the base . The voltage waveform at the collector of Q930 is α sine wave at the resonant freq uency R egulatio n occurs as follows : If the output voltage at of Τ930 . Q930 remains off u ntil α little less than one cycle the -1960 V test point starts to 9ο positive (less n egative), F937 U n reg ulated voltage from +12 Volt Rectifier, Power Supp ly Circu it Unblank ing gate from Ζ Axis Amplifier Fig . 3-16 . C RT Circ u it detailed bloc k diagram . Circuit Description-453Α/R453A ASTIG Exter n al B lank ing 0- to Ζ Axis Amp lifier 3-27

of 0914 . Q914 is forward biased and it, in turn, forward biases Q913 and Q923 . Th is results in α greater bias current to the base of Q930 through the feedback wind ing of Τ930 . Now, Q930 is biased closer to its conduction level so it comes into conduction sooner to produce α larger induced voltage in the secondary of Τ930 . Th is increased voltage appears as α more negative voltage at the -1960 V test point to correct the original positive-going change . By sampling th e output from the cath ode su pply in th is manner, the total output of the high-voltage su pply is held constant . Output voltage level of the h igh-voltage su pply is con- trolled by H igh Voltage adj ustment R900 in the base circuit of Q914 . Th is adjustment sets the conduction of Q914 to α level wh ich establishes α -1960-volt operating potential at the C RT cathode . High Voltage Rectifiers and Output H igh -voltage transformer Τ930 has three output wind ings . One winding provides filament voltage for the cathode-ray tube . The filament voltage can be supp lied from the h ig h -voltage su pply since the cathode-ray tube has α very low filament current drain . The cathode and filament are connected together through R975 to elevate the fila- ment and prevent cathode-to-filament breakdown . Two high-voltage wind ings provid e the negative and positive accelerating voltage and the C R T grid bias voltage . All of these outputs are regulated by the H igh -Voltage Regulator stage in the primary of Τ930 to hold the output voltage constant . 3-28 CRT Control Circuits Focus of the C R T display is controlled by F OCUS con- trol R967 . ASTIG adjustment R985 which is used in con- junction with the FOCU S control to provide α well-defined d isplay, varies the positive level on the astigmatism grid . Geometry adjustment R982 varies the positive level on the horizontal d eflection plate sh ields to control the overall geometry of the d isplay . Two adjustments control the trace alignment by varying the magnetic field around the C RT . Υ Axis Align ad just- ment R989 controls the current through L989 which affects the CRT beam after vertical deflection but before horizontal deflection . Therefore, it affects only the vertical (Υ ) components of the display . TRAC E ROTATIO N ad- justment R980 controls the current through L980 and affects both vertical and horizontal rotation of the beam . External Ζ Axis Input Signals app lied to the Ζ AXIS I NPUT connector (see Ζ Axis Amplifier schematic) are applied to the C RT cathode through C979-C976- R 976 . DC and low freq uency Z-axis signals are b loc ked from the C RT Circuit by C979 . How- ever, they are connected to the Ζ Axis Am plifier circuit to produce an increase or decrease i n intensity, depending upon polarity . C976 and C979 cou ple high-freq uency sig- nals d irectly to the CRT cathode to produce the same resultant d isplay as the Ζ Axis Amplifier circuit produces for low-frequency signals . Th is configuration operates as α crossover network to provide nearly constant intensity modulation from DC to 50 megahertz . Positive accelerating potential is supp lied by voltage triplex CR953, C R 955, and C R957 . Regulated voltage out- LOW-VO LTAG E POWER SUPPL Y put is about +12 kilovolts . Ground return for th is su pply is through the resistive helix inside the cathode-ray tube to General ground th rough VR963 . The Low-Voltage Power Supply circuit provides the operating power for th is instrument from three regulated The negative accelerating potential for the C R T cathode supp lies and one unregulated su pply . E lectronic regulation is supp lied by half-wave rectifier CR952 . Voltage output is is used to provide stable, low-ripple output voltages . Each about -1 .96 kilovolts . Α sam ple of th is output voltage is regulated supply contains α sh ort-protection circuit to pre- connected to the H igh -Voltage Regulator stage to provid e α vent instrument damage if α su pply is inadvertently sh orted regulated high-voltage output . to ground . The Power In put stage includes th e L ine Voltage Selector assembly . T h is assembly allows selection of the nominal operating voltage and regulating range for the in- Half-wave rectifier C R 940 provides α negative voltage for strument . Fig . 3-17 shows α detailed block d iagram of the the control grid of the CRT . Output level of th is supp ly is Power Su pp ly circuit . Α schematic of th is circuit is shown set by C R T Grid Bias ad justment R940 . Neon bulbs DS973, on d iagram 17 at the rear of th is manual . DS974, and DS975 provide protection if th e voltage d if- ference between the control grid and cathode exceed s Power Input about 165 volts . The unblanking gate from the Ζ Axis Amplifier is app lied to the positive side of th is circuit to Power is app lied to the primary of transformer Τ 1101 produce α change in output voltage to control CR T inten- th roug h the 115-volt line fuse F 1101, POWER switch sity, unblank ing, d ual-trace blanking, and intensity mod ula- S1101, thermal cutout S1104, Voltage Selector switch tion . S1102, and Range Selector switch S1103 . The Voltage

Current L imiting 01159 F ig . 3-17 . Power Supply d etailed block diagram . +75 V Feedbac k Amplifier 01184, \Ο 1193 Unregu late d +12 volts to H igh-Voltage ~` -12 V Oscillator, CRT Circuit Series Regulator rl_~ A 01137 6.3 Volt RMS Sou rce R 1107 R1108 R1104 POWWER R 1105 (~) 1 N Circuit Description-453Α/R453A +12 V Feedback Amplifier 01154, \01163 -12 V -12 V Current -,2 V Limiting -,2-V Reference 01129 Feedback VR 1114 Amplifier 01114, 01124, 01133 +75 V +12 V R 1129 --'j ί ~ -12 ν SCALE DS1107 Ι Ι LLUM Ι ~ 1 DS1108 1DS1109~ Line trigger signal to Trigger Generators 3-29

in this divider is ad- T1101 in parallel for 115-volt nominal operation, or in justable to set the output level of this supply . Regulation series for 230-volt nominal operation . Α second line fuse, occurs as follows : If the output level of this su pply de- F1102, is connected into this circuit when the Voltage creases (less negative) due to an increase in load , or α de- Selector switch is set to the 230 V position to provide the crease in input voltage (as α result of line voltage changes or correct protection for 230-volt operation (F 1102 current ripp le), the voltage across divider R 1121-R 1 122-R 1 123 Be rating is one-half of F 1101) . creases also . This results in α more positive feedback level at the base of Q1124 than established by the -12 V Refer- ence stage at the base of Q1114 . Since the transistor with Range Selector switch S1103 allows the instrument to the more positive base controls the conduction of the d if- regulate correctly on h igher or lower than normal line ferential amp lifier, the output current at the collector of voltages . E ach half of the primary has taps above and below Q1114 decreases . This decrease in output from Q1114 the nominal voltage point (115 or 230 volts) . As Range allows more current to flow through Q1133 to result in Selector switch S1103 is switched from LO to Μ to HI, increased conduction of -12 V Series Regulator Q1137, more turns are effectively added to the primary wind ing The load current increases and the output voltage of this and the turns ratio is decreased . This configuration com- supp ly also increases (more negative) . As α result, the feed- pensates for h igher or lower than normal line voltage to back voltage to the base of Q1124 returns to the same level extend the regulating range of the Low-Voltage P ower as the base of Q1 1 14 . Similarly, if the output level of this Supply . supp ly increases (more negative), the output current of Q1114 increases . The feedback through Q1133 reduces the conduction of the -12 V Series Regulator to decrease the Thermal cutout S1104 provid es thermal protection for output voltage of this su pply, this instrument . If the internal tem perature of the instru- ment exceed s α safe operating level, S1104 o pens to inter- ru pt the a pp lied power . When the temperature returns to α safe level, S1 104 automatically closes to re-apply the The -12 Volts adjustment R 1122 determines the d ivider power . ratio to the base of Q1124, and thereby determines the feedback voltage . This adjustment sets the output level of the su pp ly in the following manner : If R 1122 is adjusted so -12-Volt Supply the voltage at its variable arm goes less negative (closer to ground ), this appears as an error signal at the base of The following discussion includes the d escription of the 01124 . In the same manner as described previously, this -12 V Rectifier, -12 V Series Regulator, -12 V Feedback positive-going change at the feedback input of the differen- Am plifier, -12 V Reference, and -12 V Current L imiting tial am plifier increases the conduction of the -12 V Series stages . Since these stages are closely related in the pro- Regulator to produce more current through the load, and duction of the -12-volt regulated output voltage, their thereby increase the output voltage of this supp ly . This operation is most easily understood when discussed as α p laces more voltage across d ivider 131121-131122-131123, unit . and the d ivider action returns the base of Q1124 to about -9 volts . Notice that the feedback action of this supp ly forces α change in the output level which always returns the The -12 V Rectifier assembly CR1112 rectifies the out- base of Q1124 to the same level as the base of Q1114 . I n put at the secondary of T1 101 to provide the unregulated this manner, the out put level of the -12-Volt Su pply can voltage source for this supply . CR1112 is connected as α be set exactly to -12 volts by correct adjustment of bridge rectifier and its output voltage is filtered by C1112 R1122 . before it is applied to the -12 V Series Regulator Q1137 . Transistors Q1114, Q1124, and Q1133 operate as α feed back-stabilized regulator circuit to maintain α constant The -12 V Current L imiting stage Q1129 protects the -12-volt output level . Q1114 and Q1124 are connected as -12-Volt Supply if excess current is demanded from this α d ifferential amp lifier to compare the feedback voltage at su pply . All output current from the -12-Volt Supply must the base of Q1124 against the reference voltage at the base flow through R 1129 . Transistor Q1129 senses the voltage of Q1114 . The error output at the collector of Q1114 re- dro p across R1129 . U nder normal operating cond itions, flects the d ifference, if any, between these two inputs . The there is about 0 .3-volt drop across R 1129, which is not change in error-output level at the collector of Ο1124 is sufficient to forward bias Q1129 . H owever, when excess always in the same d irection as the change in the feedback current is demanded from the -12 V Series Regulator due input at the base of Q1124 (in phase) . to α short circuit or similar malfunction at the output of this su pply, the voltage dro p across R 1129 increases until it is sufficient to forward bias Q1129 . The collector current Zener diode VR1114 sets α reference level of about -9 of Q1129 results in α red uction of current through Q1133 volts at the base of 01114 . Α sam ple of the output voltage to decrease the conduction of Q1137 and limit the output from this su pply is connected to the base of Q1124 through current . 3-30

is filtered by C1202-C1204- R 1204 to provide an output level The unregulated voltage app lied to the +12-Volt Supply of about +150 volts . Fuse F 1204 protects th is su pply if the is also connected to the H igh -Voltage Oscillator stage in the output is shorted . CRT circuit . Two means of overload protectio n are provided for th is supply . The +75 V Current Limiting stage Q1189 operates in α manner similar to that described previously to control the co nd uction of the +75 V Series Regulator through C R 1188 and Q1193 . Ιη add ition, F 1437 provides overload protection for th is su pply . Diode CR1198 protects the +75-Volt Supp ly from damage if it is shorted to the -12-Volt Supply . +150-Volt Unregulated Supp ly 6.3-Volt RMS AC Source Oscillator Circuit Description-453Α/R453A Basic operation of all stages in the +12-Volt Supply is similar to the -12-Volt Supply . H owever, the +12 V F eed - The 6.3-volt RMS secondary winding of T1 101 provides bac k Amplifier provides inversion in the feedback path . The power for the POWER ON ligh t, DS1107, and the scale reference level for th is supply is established by the ground illumination lights, DS1108 and DS1109 . The current connection at the emitter of 01154 . Feedbac k voltage to th rough the scale illumination lights is controlled by the t h e base of Q1154 is p rovi d ed by divider SCALE Ι LLUM control, R1108,tochange theillumination R1151-R 1152-R 1153 between the output of th is supply of the graticule lines . Divider R1104- R 1105 provides α and regulated -12 volts . The -12 volts is held stable by the samp ling of the line voltage to the Α and Β Trigger Gen- -12-Volt Su pply as d iscussed previously . T herefore, any erator circuits for internal triggering at the line freq uency . change at the output of the +12-Volt Supp ly appears at the C1105 reduces noise on the line frequency signal . base of Q1154 as an error signal . The output voltage is regulated in the manner described previously for the -12-V olt Su pply . Diode C R 1152 provides thermal compen sation for th e +12 V Feedback Am plifier . C R 1164 protects VO LTAGE DIST R I BU TION Q1154 from damage if the output of th is supp ly is shorted to α more positive sup ply . Diagram 17 also shows the d istrubution of th e output voltages from the Power Supply curcuit to the circuit boards in th is instrument . The decoupling networks which provid e decoupled operating voltages are shown on th is +75-Volt Supply Diagram and are not repeated on the ind ivid ual circ u it Operation of the +75-Volt Supply is the same as de- d iagrams . scribed for the other supp lies . The unregulated output of the +150-Volt Supply is connected to the +75 V F eedback CAL I BRATO R Am plifier to provide sufficient collector supply for stable operation . The unregulated +150 volts connected to zener General diode VR 1209 through R 1209 establis h es α voltage level at the cathod e of V R 1209 of abo ut +108 volts . The drop The Calibrator circuit produces α square-wave output across R1186 sets th e correct base level for Q1193 and the with accurate amplitud e and frequency . T h is output is d rop across V R 1185-R 1 185 sets the correct collector level available as α square-wave voltage at the 1 kH z CAL connec- for Q1184 . Diode C R 1182 provides thermal compensation for or as α sq uare-wave current th rough the side-panel for the +75 V Feedback Amp lifier . PRO BE LOOP . F ig . 3-18 shows α detailed block d iagram of the Calibrator circuit . Α schematic of th is circuit is shown on d iagram 18 at the rear of th is manual . Q1255 and its associated circ u itry comprise α tuned- collector oscillator . Frequency of oscillation is determined by the LC circuit made up of the primary of variable trans- former Τ 1255 in parallel with C1255 . The accuracy and stability required to provide an accurate time and fre- quency reference is obtained by using α ca pacitor and trans- former which have equal but opposite temperature co- efficients . Rectifiers CR 1202 and C R 1212 provide the rectified voltage for the +150-Volt Su pply . However, th is secondary T he oscillations of the LC circuit, Τ 1255-C1255, are sus- winding of Τ 1101 does not su pply the full potential tai ned by the feed back wind ing of Τ 1255 connected to the necessary to obtain the +150-volt output level . To provide base of Q1255 . C1266 connects α sam ple of th e output of the required output level, the negative side of th is supply is th e LC circuit to the base of Q1265 . The regenerative feed- connected to the output of the +75-Volt Supply so the two back from the emitter of Q1265 to the emitter of Q1255 su pplies are effectively connected in series between ground produces fast changeover between Ο1255 and 01265 to and the +150-volt output . The output from th is secondary provide α fast risetime on the output square wave . Fre- wind ing of TI 101 also provides the operating potential for quency of the output square wave can be adjusted by 3-3 1

Calibrator detailed block diagram . PROBE LOOP - 5 mASL varying the coup ling to the feedback winding of Τ 1255 . Output D ivider The square-wave signal at the collector of Q1265 is con- nected to the Output Amplifier . Output Divider 131275-R1276-131277 provides two out- put voltages from the Calibrator circuit . In the 1 V CALI Output Amplifier BRATOR switch position, voltage is obtained from the The output signal from the oscillator stage saturates collector of Q1274 through R1274 . In the .1 V CALI- Q1274 to produce the accurate square wave at the output . BRATOR switch position, the output is obtained at the When the base of Q1274 goes positive, Q1274 is cut off and junction of voltage divider R1275 and 131276-131277 to the output signal drops negative to ground . When its base provide one-tenth of the previous output voltage . goes negative, Q1274 is driven into saturation and the out- put signal rises positive to about +12 volts . The output of the +12-Volt Supply is adjusted for an accurate one-volt Collector current of Q1274 flows through the PROBE output signal at the 1 kHz CAL connector when the LOOP on the side panel . Output current is α five- CALIBRATOR switch is set to 1 V . milliampere square wave .

mation for use in preventive maintenance, corrective mai n - tenance, or troubleshooting of the 453Α . General P reventive maintenance consists of cleaning, visual inspection, lubrication, etc . P reventive maintenance, per- formed on α regu lar basis may prevent instrument break - down and will im prove th e reliability of th is instrument . The severity of th e environment to wh ich the 453Α is sub- jected d etermines the frequency of maintenance . Α conven- ient time to perform preventive maintenance is preced ing recalib ration of the instrument . Cleaning PREVENTIVE M AI N TENANC E General . The 453Α should be cleaned as often as oper- ating conditions req uire . Accumulation of d irt in th e instru - ment can cause over-heating and com ponent breakdown . Dirt on components acts as an insu lating blanket and pre- vents efficient heat dissi pation . It also provides an electrical cond u ction pat h . CAUTION SECTION 4 MAINTENANCE Change information, if any, affecting this section will be found at the rear of this manual. 453Α/R453A the covers in place necessitates more freq uent cleaning . The front cover provides dust protection for the front panel and the C R T face . Th e front cover sh ould be installed for stor- age or transportation . Cover Removal Air Filter . The air filter should be visually check ed The to p and bottom covers of the instrument are held in every few weeks and cleaned or replaced if d irty . More p lace by thumb screws located on each side of th frequent inspectio ns are required under severe operati ng e instru- ment . To remove th e covers, conditions . The following procedure is suggested for clea n - slide the covers off the instrument . the th umb screws and ing the filter . If th e filter is to be replaced , order new air . The covers protect the filters from your local Tektronix Field Office or represen t- instrument from d ust in the interior . The covers also direct ative ; ord er by Tektronix Part No . 378-0033-00 . the flow of cooli ng air a nd reduce the EMI radiation from the instrument . 1 . Remove the filter by pulling it out of the retaining frame on the rear panel . Be careful not to drop any of the accumulated d irt into the instrument . 2 . F lus h the loose dirt from the filter wit h α stream of hot water . 3 . P lace the filter in α solution of mild detergent and hot water and let it soak for several minutes . 4 . Squeeze the filter to was h out any dirt wh ich remains. 5 . Rinse the filter in clear water and allow it to dry . 6 . Coat the d ry filter with an air-filter adhesive (available from air conditioner su ppliers, or order Tektronix Part No . 006-0580-00) . 7 . Let the adhesive d ry thorough ly . 8 . Re-install the filter in the retain ing frame . Avoid the use of chemical cleaning agents which might damage the plastics used in this instrument. Avoid chemicals which contain benzene, toluene, E xterior . Loose d ust accumulated on the outside of the xylene, acetone, or similar solvents. 453Α can be removed with α soft cloth or small brush . The brush is particularly useful for d islodging dirt on and around the fro nt-panel controls . Dirt wh ich remains can be The top and bottom covers provide protection again st removed with α soft cloth dampened in α mild d etergent d ust in the interior of the instrument . O peration wit hout and water solution . Abrasive cleaners should not be used .

CR T . Clean the p lastic ligh t filter, faceplate protector, Fan . The fan-motor bearings are sealed and d o not re a nd the C RT face with α soft, lint-free cloth dampened with quire lubrication . denatured alcohol . The optional C RT mesh filter can be cleaned in the following manner . d ust-proof container such as α plastic bag . Visual Inspection 1 . Hold the filter in α vertical position and brush lightly The 453Α should be inspected occasionally for such with α soft Νο .7 water-color brus h to remove lig ht coatings defects as b roken connections, bro k en or damaged ceramic of d ust or li nt . stri ps, impro perly seated transistors, damaged circuit board s, and heat-damaged parts . 2 . Greasy resid ues or dried-on dirt can be removed with α solution of warm water and α neutral-pH liquid detergent . The corrective procedure for most visible defects is ob vi Use th e brush to lightly scrub the filter . ous ; h owever, particular care must be taken if heat-damaged components are found . Over-heating usually indicates oth er trouble in the instrument ; therefore, it is important that the 3 . Rinse the filter thorough ly i n clean water and allow to cause of over-heating be corrected to prevent recurrence of air dry, the damage . 4 . If any li n t or d irt remains, use clean low-pressure air Trans i stor Checks to remove . Do not use tweezers, or other hard cleani ng Period ic checks of the transistors in the 453Α are not tools on the filter, as the special finish may be damaged . recommended . The best check of transistor performance is actual operation in the instrument . More details on check - 5 . When not in use, store the mesh filter in α lint-free, i ηg transistor operation are given under Troub leshooting . Recalibration Interior . Dust in the interior of the instrument should To assure accurate measurements, check the calibration be removed occasionally due to its electrical cond uctivity of th is instrument after each 1000 hours of o peration or under h igh -humid ity cond ition s . The best way to clean the every six months if used infrequently . In addition, rep lace- interior is to blow off the accumulated dust with d ry, low- ment of components may necessitate recalibration of the velocity air . Remove any dirt which remains with α soft affected circuits . Complete calibration instructions are brush or α cloth dampened with α mild detergent and water given in the Calibratio n section . solutio n . Α cotton-tipped applicator is useful for cleaning in narrow spaces or for cleaning ceramic terminal strips and circuit boards . T he calibratio n proced ure can also be helpful in local- izing certain troubles in the instrument . In some cases, The high-voltage circuits, particularly parts located in minor troubles may be revealed and/or corrected by recali- the high-voltage compartment and the area surround ing the oration . post-deflection anod e connector, should receive special attentio n . E xcessive dirt in these areas may cause h ig h - TRO UBLESHOOTI N G voltage arcing and result in improper instrument operation . Lubrication 4-2 Introduction The following informatio n is provided to facilitate General . The reliability of potentiometers, rotary troublesh ooting of the 453Α . Information contained in switches and other moving parts can be maintained if th ey other sections of th is manual should be used along wit h the are kept properly lubricated. U se α cleaning-type lubricant following information to aid in locating the defective com- (e .g ., Tektronix Part No . 006-0218-00) on switch contacts . ponent . An understanding of the circuit operation is very L ubricate switch detents with α heavier grease (e .g ., Tek - hel pful in locati ng troubles . See the Circuit Descri ption tronix Part No . 006-0219-00) . Potentiometers wh ich are section for complete information . not permanently sealed should be lubricated with α lubri- cant which does not affect electrical characteristics (e .g ., Tektronix Part No . 006-0220-00) . The pot lubricant can also be used on shaft bushings. Do not over-lubricate . Α Troubleshooting Aids lubrication kit containing the necessary lubricants a nd instructions is available from Tektronix, I n c . Order Tek - Diagrams . Comp lete circuit diagrams are given on fold - tronix Part No . 003-0342-01 . out pages in the Diagrams section . The component number

necting wires and /or connectors . The circuit board s are also are show n on the diagrams (see first page of th e Diagrams outlined on the diagrams with α blue li ne to show w hich section for definition of the reference designators used to portions of the circuit are located on α circuit board . ide n tify components in th is instrument) . Each main circuit is assigned α series of component numbers . Tab le 4-1 lists the main circuits in the 453Α and the series of com po nent Wiring Color-Code . All insulated wire and cable used in numbers assigned to each . Important voltages and wave- the 453Α is color-coded to facilitate circuit tracing . Signal forms are also shown on the diagrams . The portions of the carrying lead s are identified with one or two colored circuit mounted on circuit boards are enclosed with blue stripes . Voltage su pply leads are identified with three lines . stripes to ind icate the approximate voltage using the ΕΙΑ resistor color cod e . Α white backgrou nd color indicates α positive voltage and α tan background ind icates α negative TABLE 4-1 voltage . The widest color stripe identifies the first color of Component Numbers the code . Table 4-2 gives the wiring color code for the power-supp ly voltages used in the 453Α . Component Numbers on Ι Diagram Diagrams N umber Circuit TABLE 4-2 Power Supply Wiring Color Code 1-99 1 Channel 1 Vertical Pream p 100-199 3 C hannel 2 Vertical Pream p Back - 200-299 5 Vertical Switch ing ground First Second Th ird 300-399 6 Vertical Output Amplifier Su pply Color Stripe Stripe Stripe 400-429 7 Trigger Preamp 430-499 8 Α Trigger Generator -12 volt Tan Brown Red Black 500-599 9 Α Sweep Generator +12 volt White Brown Red Blac k 600-699 10 Β Trigger Generator +75 volt White V iolet Green Black 700-799 11 Β Sweep Generator +150 volt Wh ite Brown Green Brown 800-899 13 H orizontal Amp lifier 900-999 16 C R T Circuit 1000-1099 15 Ζ Axis Amplifier Resistor Color-Code . In add ition to the brown compo- 1100-1199 17 Power Su pply and sition resistors, some metal-film resistors and some wire- Distrib ution wound resistors are used in the 453Α . Th e resistance values 1250-1299 1 18 1 Calibrator of wire-wound resistors are printed on the bod y of the component . The resistance values of composition resistors and metal-film resistors are color-coded on the com ponents Switch Wafer Identification . Switch wafers shown on t he with ΕΙΑ color-code (some metal-film resistors may have diagrams are coded to indicate the position of the wafer in the value printed on the body) . The color-cod e is read start- the complete switch assembly . The numbered portion of ing with the stri pe nearest the end of the resistor . Compo- the code refers to the wafer number counting from the sition resistors have four stripes w hich consist of two sign if- front, or mounting end of the switch , toward the rear . The icant figures, α multiplier, and α tolerance valu e (see F ig . letters F and R indicate whether the front or rear of the 4 - 1) . M etal-film resistors have five stripes consisting of th ree wafer performs the particular switch ing function . F or significant figures, α multip lier, and α tolerance value . example, α wafer designated 213 ind icates that the rear of the second wafer from the front is used for th is particular switch ing fu nction . Capacitor Marking . T he capacitance values of common d isc capacitors a nd small electrolytics are marked in micro- farads on the side of the com ponent body . The white ceramic capacitors used in the 453Α are color coded in Circuit Boards . F ig . 4-4 shows the location of the circuit picofarads using mod ified ΕΙΑ code (see F ig . 4-1) . boards with in th is instrument along with the assembly numbers . The assembly numbers are also used on the d ia- grams and in the parts list to aid in locating the boards . Diode Color Code . The cathod e end of each glass- Pictures of the circuit boards are shown in Figs . 8-1 through encased diode is ind icated by α stripe, α series of stri pes, or 8-14 . These pictures are located in the Diagrams section, on α dot . F or most silicon or germanium d iodes with α series of the back of the page opposite the circuit d iagram, to aid the stripes, the color-code also identifies the Tektronix Part cross-referencing between the diagrams and the circuit- Number using the resistor color-code system (e .g ., α d iod e board p ictures . Each electrical component on the boards is color-cod ed pink -, or blue-brown-gray-green ind icates Tek - identified by its circuit number as well as the intercon- tronix Part N umber 152-0185-00) . The cathod e and anod e 4-3

Silve r Ι - - - Ι 10 - 2 Ι - - - Ι ±10% --- ' I ' . Gold I --- Ι 10-1 Ι --- ±5% -- Blac k 0 1 1 --- ±20% o r 2 pF* Brow n 1 10 10 ±1 % :±-l % or _ 0 .1 pF* Red Ι 2 Ι 10 2 10 2 ±2% Ι ±2% O range 3 Ι 10 3 Ι 10 3 Ι ±3% Ι =3 % Yellow Ι 4 Ι 10' Ι 10' Ι ±4 01. +100 0/0 -0%ο _ ±0.5 Metal-Film Resisto rs: Ceramic Capacito rs: 1 . Transistor Tester Troubleshooting E quipment Transistor Lead Configuration . F ig . 4-2 shows the lead configu rations of the transistors used in th is instrument . Th is view is as seen from the bottom of the transistors . The following equi pment is useful for troubleshooting the 453Α . Descri ption : Tektronix Ty pe 576 Tra nsistor-Curve Tracer or eq uivalent . Purpose : To test the semicond uctors used in th is instru- ment . F ig . 4-1 . Color code for resistors and ceramic capacitors. Resisto r a nd Capacitor Color Code Bl ue Ι 6 Ι Violet Ι 7 Ι Gray Ι 8 Ι --- Ι 10 -2 Ι --- Ι +80% -20% or 0.25 pF * (D@ and 3Ο -1st, 2nd and 3rd sign ificant fig ures; *For capacita nce of 10 pF or less. -mu ltip lier; ΟΤ -tole rance ; 9-temperature coefficient . NOTE : Ο and/or @. color code fo r ca pacito r s depends upon manu facture r and capacitor type. May not be prese n t in some cases . end of metal-encased d iodes can be identified by the diode within 3% . Test probes must be insulated to prevent acci- symbol marked on the body . dental shorting . Purpose : To check voltages and for general trouble- shooting in th is i n stru ment . NO ΤΕ Α 20,000 ohmslνο lt VOM can be used to check the voltages in th is instrument if allowances are made for the circuit loading of the VOM at high-impedance points . 3 . Test Oscilloscope Descri ption : DC to 20 megahertz freq uency response . 5 millivolts to 10 volts/d ivision deflection factor . U se α 10Χ probe . P urpose : To check waveforms in th is instrument . 2 . M ultimeter Troubleshooting Techniques Description : VTVM, 10 mego h m in put imped ance and 0 T h is troubleshooting proced ure is arranged i n an order to 500 volts range ; oh mmeter, 0 to 50 megohms . Accuracy, wh ich ch eck s t he sim ple possibilities before proceed ing 4-4

® ® Drain Plastic-Cased Transistors Metal-Cased Transistors F ield-Effect Transistors Fig . 4-2 . Electrode config uration for semiconductors in th is in str ument . ι ι ~ι ~ ,~. / ~/ C Maintenance-453Α/R 453A with extensive troubleshooti ng . The first few check s assure used with th is instrument is operati ng correctly . Check that proper connection, operation, and calibration . If the the signal is properly connected and that th e intercon - trouble is not located by th ese check s, the remaining steps necting cables are not defective . Also, check the power aid in locating the defective component . When the defective source . component is located , it should be replaced following the rep laceme n t proced ures given u nder Corrective M ainten- 3 . Visual Check . Visually check the an ce . Υ portion of the instrument in wh ich the trouble is located . Many troubles can be located by visual ind ications such as unsoldered 1 . Check Control Settings . Incorrect control settings can connection s, bro k en wires, d amaged circ u it boards, dam- ind icate α trouble that does not exist . If th ere is any aged compone nts, etc . question about the correct function or o peration of any control, see the Operating I nstructio n s section of th is 4 . Check Instrument Calibration . Check the calib ration manual . of th is i n strument, or the affecte d circuit if the troub le exists in one circuit . The appare nt trouble may only be a result of mis-adjustment or may be corrected by cali- 2 . Check Associated Equipment . Before proceed ing with bration . Complete calibration instructio ns are given in the troubleshooting of the 453Α , check that the eq uipment Calibration section of th is manual . Ϊ,\ ~ί' So urce So urce 4-5

isolate trouble to α The circuit board pictures in Section 8 show the correct circuit, note the trouble symptom . T he symptom often con nections for each board . identifies the circu it in which the troub le is located . F or examp le, poor focus i ndicates that the C RT (i ncludes h igh voltage) circuit is probably at fault . When trouble sym p- T he pin connectors used in th is instrument also provide toms appear in more than one circuit, check affected cir- α convenient means of circuit isolation . F or exam p le, α cuits by tak ing voltage and waveform read ings . Also check short in α power su pply can be isolated to the power supply for the correct output signals at the side-panel output con- itself by d isconnecting the pin connectors for that voltage nectors with α test oscilloscope . If the signal is correct, the at the remaining boards . circuit is work ing correctly up to that point . F or exam ple, correct amplitud e a nd time of the Α gate out waveform indicates that the Α Trigger Generator and Α Sweep Gate 7 . Check Voltages and Waveforms . Often the defective circuits are operating correctly . component can be located by check ing for the correct volt- age or waveform in the circuit . Ty pical voltages and wave- forms are given on the d iagrams. Incorrect operation of all circuits often ind icates trouble in the power su pply . Ch eck first for correct voltage of the individual supplies . However, α defective component else- where in the instrument can a ppear as α power-su pp ly trouble and may also affect the operation of other circuits . Table 4-3 lists the tolerances of the power su pplies in th is instrument . If α power-su pply voltage is with in the listed tolerance, the su pply can be assumed to be work ing cor- rectly . If outside the tolerance, the supply may be mis- adjusted or operating incorrectly . Use the procedure given in the Calibration section to adjust the power supp lies . Power Supply TABLE 4-3 Power Supply Tolerance Tolerance ΝΟΤΕ Voltages and waveforms given on the diagrams are not absolute and may vary sligh tly between instru - ments. To obtain operating conditions similar to those used to take these readings, see the first dia- gram page. 8 . Check Individual Components . Th e following pro- cedures describe methods of check ing ind ivid ual com po- nents in the 453Α . Components wh ich are sold ered in place are best checked by d isconnecting one end . Th is isolates the measurement from the effects of surrounding circuitry . -12 volt ±0.12 volt Α . T R AN SISTO R S . The best check of transistor oper- +12 volt 12 .1 volts, ±0.12 volt' ation is actual performance under o perating cond itions . If α transistor is suspected of being defective, it can best be +75 volt ±0.75 volt checked by substituting α new component or one wh ich has -1960 volt ±58 .5 volts been checked previously . H owever, be sure that circuit con- ditions are not such that α replacement transistor might also 'Adju sted for correct ou tput from the Cali brator circuit ; see Cali- be damaged . If substitute transistors are not availab le, use α bra τion procedu re . dynamic tester (such as Tektronix Type 576) . Static-type testers are not recommend ed , since they do not check oper- ation under simulated operating conditions . F ig . 4-3 provides α guide to aid in locating α defective circuit . T h is chart may not include check s for all possi ble defects ; use steps 6-8 in such cases, Start from the top of Β . DIOD ES . Α d iode can be checked for an open or the chart and perform the given ch eck s on the left side of shorted cond ition by measuring the resistance between the page until α step is found wh ich is not correct . F urther terminals . Wit h an oh mmeter scale having an internal source checks and/or the circuit in wh ich the trouble is probably of between 800 millivolts and 3 volts, the resista nce should located are listed to the right of th is step. be very h ig h in one direction and very low when the leads are reversed . After the defective circuit has been located, proceed with ste ps 6 through 8 to locate the defective com po- nent(s) . Do not use an ohmmeter scale that has α high internal current. High currents may damage the diode . Do not 6 . Check Circuit Board Interconnections . After the measure tunnel diodes with an ohmmeter, use α trouble has been isolated to α particular circuit, check the dynamic tester (such as α Tek tronix Type 576 pin connectors on the circuit board for correct connection . Transistor-Curve Tracer) . 4-6

Special Parts . i n addition to th e standard electronic com- Check the Electrical Parts L ist for the tolera n ce of the resis- ponents, some special com ponents are used in the 453Α . tors used in this instrument . Resistors normally do not need These components are ma nufactured or selected by Tek - to be replaced unless th e measured value varies widely from tronix, Inc . to meet specific performance requirements, or the specified value . are manufactured for Tektronix, Inc . in accordance with our specifications . Th ese special components are indicated in the E lectrical Parts L ist by an asterisk preceding the part D . I N D UCTO R S . Ch eck for open inductors b y check ing number . Most of the mechanical parts used in this instru- continuity with an o h mmeter . Shorted or partially shorted ment have been manufactured by Tektronix, Inc . Order all inductors can usually be found by check ing the waveform special parts d irectly from your local Tektronix F ield response wh en h igh -freq uency signals are passed through Office or representative . the circuit . Partial shorting often reduces h igh-frequency response (roll-off) . Ordering Parts . When ord ering replacement parts from Tek tronix, Inc ., include th e following information : Ε . CAPACITO R S . Α leaky or shorted capacitor can best be detected by checking resistance with an ohmmeter on 1 . I nstrument type . the highest scale . Do not exceed the voltage rating of th e capacitor . The resistance read ing should be high after initial 2 . Instrument serial number . charge of the capacitor . An open capacitor can best be d etected with α capacitance meter or by check ing whether 3 . Α description of the part (if electrical, include circuit the ca pacitor passes AC signals . number) . 4 . Tektronix Part N umber . 9 . Repair and Readjust the Circuit . If any defective parts are located, follow the rep lacement procedures given in this sectio n. Be sure to check the performance of any circuit Soldering Tech niques that has been repaired or that has had any electrical compo- nents rep laced. WARNING General The reliability and accuracy of this instrument can be Corrective maintenance consists of component rep lace- maintained only if proper soldering techniq ues are used ment and instrument repair . Special tech niques required to when repairing or replacing parts . General soldering tech- replace components in th is instrument are given here . niques wh ich apply to maintenance of any precision elec- tronic equi pment should be used when work ing on th is instrument . Use only 60/40 rosin-core, electronic-grade Obtaining Replacement Parts solder . The choice of soldering iron is determined by the repair to be made . When soldering on circuit boards, use α Standard Parts . All electrical and mechanical part re- 35- to 40-watt pencil-type soldering iron with an 1/8-inch placements for the 453Α can be obtained through your wide, wedge-sha ped ti p. Keep the tip properly tinned for local Tektronix F ield Office or re presentative . H owever, best heat transfer to the solder joint . Α higher wattage many of the standard electronic components can be ob- solderi ng iron may separate the wiring from the base mater- tai ned locally in less time than is req uired to order them ial . Avoid excessive heat ; app ly only enough h eat to remove from Tektronix, Inc . Before purchasing or ordering replace- the component or to make α good solder joint . Also, apply ment parts, check the parts list for value, tolerance, rating, only enough solder to make α firm solder joint ; do not and descri ption . apply too much solder . Disconnect the instrument from the power source CO RRECTIVE MAI NT ENANCE before soldering. NOTE For metal terminals (e .g ., switch terminals, potenti- ometers, etc .), α high er wattage-rating soldering iron may be When selecting replacement parts, it is important to required . M atch the soldering iron to the work being done . remember that the physical size and shape of α com- For example, if the component is connected to th e chassis ponent may affect its performance in the instrument, or other large heat-rad iating surface, it will require α particularly at high frequencies . Α // replacement parts 75-watt or larger sol dering iron . The pencil-type sold ering should be direct replacements unless it is known that iron used on the circuit boards can be used for soldering to α different component will not adversely affect switch terminals, p otentiometers, or metal terminals instrument performance . mou nted in plastic holders . 4-7

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