Phase Distortion in FM Satellite Communication Systems

Wide deviation FM techniques employed in satellite communications require careful control of envelope delay distortion in the communications signal path to minimize phase distortion noise. This system impairment is more significant in satellite systems because of the high test tone deviations required. This paper highlights important characteristics of both terrestrial and satellite systems with emphasis on the latter. Methods for determining envelope delay coefficients and their conversion into picowatts of noise in frequency-division multiplexed (FDM) telephone channels and noise power ratio (NPR) amplitudes are included.