PSK Combiners for Fading Microwave Channels

The signal-to-noise (S/N) ratio of digital signals can be improved by using diversity transmission, followed by combining at the receive end, resulting in a lower probability of error P(e) . Second-order combining schemes for data signals are presented in this paper. The effect of delay difference in the two channels of a diversity system is analyzed, using four-phase coherent, phase-shift keying (PSK) as an example. For comparison with predicted performance, experimental results are included.