Power Spectra of Computer Simulated Frequency Modulation with Digital Minimum Shift Keying and Voice Input

摘要

A FORTRAN computer program, FMSPECT, which obtains the power spectrum of an FM signal, modulated by a voice signal, a digital signal, and combinations of both is presented. The theory behind the simulation of the voice signal (265-5575 Hz) is described, as well as the theory of simulating an MSK digital signal (2400 bits-per-second). The digital signal is multiplexed onto the voice at 7200 Hz for combined transmission. Sample spectra are shown for various modulation conditions, and the results are presented in the form of graphs and tables. A listing of the program is given in the appendix. (Author)