Clock recovery for on-board regeneration in a TDMA satellite communication system

Clock recovery at the on-board receiver of a regenerative satellite using 4phi-DCPSK modulation in the uplink is analyzed by computer simulation. The results show that simple baseband circuits consisting of half-wave or full-wave rectifiers followed by an adder and a single-tuned resonant filter and applied directly to the differentially demodulated signals are well suited to provide a rapid and correct acquisition of the timing synchronization. It is found that the full-wave rectifier scheme is still valid when a limiter, that is, a saturating amplifier, is included in front of the on-board differential demodulator. The computer simulation here is restricted to a particular model of the uplink transmission chain, and many conservative hypotheses are assumed for the BER evaluation.