Generalized Theory of Multitone Amplitude and Frequency Modulation

The frequency spectrum produced by single-tone, two-tone, and multitone modulating signals in the case of amplitude modulation, frequency modulation, and combined amplitude and frequency modulation are studied in turn. Amplitude, symmetry, and energy of sidebands for the different cases are considered. Extensive computations are made of frequency spectrums, and these are compared with actual frequency spectrums observed by means of a spectrum analyzer. The agreement between computed and measured frequency spectrums is very close.