Antenna Computer

Antcom demodulates the FSK signal into 250 Kbits/sec data, regenerates 250 KHz clock using Digital Phase Lock Loop,look for sync. bits and if matches with no error or one bit error then demultiplexes the data into COMMAND, VOICE, DIAL PULSE AND AUX. DATA and passes them to respective circuits for further processing. (VDM)

The STATE MACHINE shows the functions of the SYNC. DETECTOR.

The user commands are processed and sent to the various systems as follows.

• SERVO commands to SCC thro' link E.
• MCM and FPS commands thro' link D.

  In the return link,the ANTCOM gets the monitoring information from SCC,MCMs(5) and FPS and form a packet of SDLC/HDLC data and multiplxes it voice,phone Hook Status and AUX. channels into a single bit stream, convets it into FSK @ 4.5 MHz.The UP converter upconverts this IF into 205.5 MHz signal using regenerated 201 MHz as the LO carrier.This FSK signal is sent along with the IF signals (CH.1 and CH.2 ) of 32 MHz bandwidth each to CEB (RETURN LINK).Thirty CEBCOMs at CEB retrieves the monitoring information from the respective antennas and passes them to COMH thro' MUX 32 card.Also the voice signals from all the antennas are routed thro' EPABX system for TELEPHONE conversation.

  Next,let us see how the C & M system handles voice communication.