An improvement effect by a hard-limiter on differential detection performance of PSK in frequency-selective fading

Differential detection of PSK after an IF hard-limiter is described. This detection scheme is well known for the reason that the receiver structure is greatly simplified with saturated amplifiers and a digital-type differential detector. In addition, it can give the improved effect of reducing eye pattern timing fluctuation which is found to be a cause of excessive errors in a frequency-selective fading channel. Error rates were measured for binary and quadrature phase-shift keying. The results show great improvement over the detection scheme employing linear amplifiers and an analog differential detector.