DRAKE 1002366 Manuals

Installation 2 INTRODUCTION The 1002366 board is used to process the transport stream after satellite demodula- tion and before QAM modulation. It enables the FIXED CLOCK mode of operation (AUTO CLOCK mode is still selectable), performs PCR correction, and it also provides an ASI output of the demodulated transport stream. TRANSPORT STREAM PROCESSING The transport stream processing feature of the 1002366 board will add null packets if the SCT860 is set to the FIXED CLOCK mode and the demodulated transport stream data rate is less than the rate set as the fixed output rate. The 1002366 can also drop extra null packets from the transport stream when required to obtain the desired output rate. The standard SCT860 does not modify the transport stream - Drake labels this mode the ‘AUTO CLOCK’ mode as the output rate is automatically determined by the received input signal data rate. When the SCT860, with the 1002366 installed, is set to the AUTO CLOCK mode setting, it operates as if the board were not installed; the null packets will not be processed and neither dropping or adding will occur. The 1002366 option board must be installed into the SCT860, and the SCT860 firmware must be updated, in order to activate the FIXED CLOCK mode. The null packet processing functions are enabled in the FIXED CLOCK mode. The AUTO CLOCK mode can still be selected in the menu. When the SCT860, with the1002366 board, is set to the FIXED CLOCK setting, all null packets will be dropped from the demodulated transport stream. The rate is then built back up, by adding 1 TM Model 100-2366 Packet Processing/ASI TS Output Option Board (SCT860) null packets, to the fixed output QAM symbol (baud) rate that is set via the front panel. Dropping null packets is required in some cases in order to bring the rate down to or below the desired rate when the satellite uplink may add extra null packets. PCR CORRECTION The SCT860 performs PCR correction on the processed transport stream before QAM modulation when the SCT860 is used with the 1002366 option and is set up in the FIXED CLOCK mode. No PCR adjustments are made when the unit is set to the AUTO CLOCK mode. ASI OUTPUT The 1002366 option board also adds an ASI transport stream output connector to the SCT860. A chassis mount type BNC connector with coaxial cable is provided for those who have a requirement for this feature. The ASI output will be the de- modulated satellite signal transport stream output, without processing. It is provided in DVB ASI format. This output may be used to feed the satellite signal transport stream to a multiplexer where part of the stream may be needed for remultiplexing with another stream for another output channel. If ASI output is not a requirement, place the connector assembly in a storage location for possible future use. If the ASI output feature is desired, plug in the supplied BNC connector cable to the SCT860 PC board as indicated in Figure 3 and mount the BNC connector in the rear panel mounting hole. If your SCT860 does not have this hole, it must be added. The unit can be returned to the Drake Service Department, if necessary, for this installation. INSTALLATION IN THE SCT860 Looking at the SCT860 from the front panel, observe the right side of the unit. Remove the three top screws as shown, three side screws, and three bottom screws holding the right side of the case. 3 TOP SCREWS Remove the right side and then lay the transcoder on a flat surface laying on its left side. Locate the 36 pin interface connector and remove the 11 jumpers that are in place. Keep these jumpers for future use in case the 100-2366 board is ever removed. REMOVE 11 JUMPERS FROM THE 36 PIN CONNECTOR LOCATION A