Regenerative SCPC satellite communications systems

The design concept of a regenerative SCPC satellite communications system is developed, and preliminary test results on components are reported. FDMA uplink signals are regenerated and TDM multiplexed for downlink transmission; network clock synchronization is imposed; and a frequency extraction and retransmission (FERT) scheme which matches transmitted-frequency stability to that of the satellite reference frequency is used to maintain Pe performance and limit adjacent-channel interference. The realization of these concepts is discussed and illustrated with a block diagram, and the results of experimental studies of the FERT scheme, a prototype digital transmultiplexer, and a digital QPSK demodulator, are presented graphically. Good agreement is found with theoretical predictions, and substantial reductions in onboard-component weight and power consumption are achieved.