Abstract: In this paper, we emphasize on analyzing the application of ⅡR filter feedback differential detection in differential demodulation of π/4DQPSK. The practical implementation scheme is presented. The BER performance and its correction capability are investigated by computer simulation in AWGN channel. The simulation results show that the improved performance of proposed algorithm is superior to conventional differential demodulation by 1.2dB at a BER of 10-4 in AWGN channel. Considering that the loss of implementation and the test result of practical system agree with the simulation result, the algorithm can be widely applied in practical satellite communication system, thereby improving the system's traditional differential detection and the capacity and communication quality of a satellite communication system with limited power.

Key words: IIR filter feedback differential detection, π/4 DQPSK demodulation, satellite communication system