Power Spectrum of PAM/FM and PAM/PM

Abstract

Mathematical expressions are obtained for FM and PM power spectra when the modulating waveform is a constantrate random sequence of nonoverlapping pulses with arbitrary shape and amplitude distribution. These expressions essentially reduce the computation of power spectrum to the computation of the average energy spectrum of a section of the wave only two pulses in length. The results are applied to the special PAM/FM case where the modulating pulses have a rectangular shape and uniformly distributed amplitude. Spectra are plotted for several values of the deviation ratio. Results are also given for the much simpler case of binary PAM/PM for arbitrary phase deviations.