Preemphasis/Deemphasis Effect on the Output SNR of SSB-FM

The effect of preemphasis/deemphasis on the noise power output of FM detectors for SSB-FM is studied. Two cases are considered: namely, when the modulating signal is assumed to be sinusoidal and when it is a Gaussian random process. For both cases the noise is assumed to be stationary and Gaussian. For a sinusoid modulating signal, the improvement of(S/N)_{0}for SSB-FM detectors is obtained when the modulation index β lies in the interval (0.1-12.0) with negligible improvements for higher β. For a Gaussian modulating signal, improved results are obtained for a modulation index in the interval (0.1-0.6).