Discriminator Response to an FM Signal in a Fading Channel

The response of an FM discriminator to a fading FM signal in additive Gaussian noise is obtained. The technique employed is based on the model of an FM discriminator proposed by Rice and extends his results of SNR (above, at, and below threshold) to the fading environment. While the technique employed is quite general, examples considering Rayleigh fading, and sinusoidal and Gaussian modulation are given. The use of diversity to combat threshold degradation is studied and the threshold of a discriminator using predetection combining diversity is found. Experimental results are shown to verity the theory.