Effects of Random Fluctuation Noise on FM and FDM/FM Reception

Abstract

A tutorial review and analysis of the effects of random noise upon the output of a conventional FM demodulator is presented. The mechanism by which these effects are produced is conveniently brought out with the aid of phasor diagrams. Illustrative computations are given of the smooth and impulsive components of the output noise and of output signal-to-noise power ratios for various types of frequency modulation. Various types of thresholds are pointed out and the practical significance of threshold reduction as a system design optimization tool is discussed.