Spectrum of Frequency-Shift Radio Photo-Transmissions

The spectrum of frequency-shift and subcarrier frequency-shift radio-photo transmissions are obtained from the general expression for the spectrum of a carrier which is frequency modulated with a triangular pulse. A simplified asymptotic expression for rapidly determining the high order sideband amplitudes is developed along with expressions for the interfering bandwidths of radio-photo transmissions. The effect of shaped apertures in the radio-photo scanner upon the output frequency spectrum is discussed. Experimentally determined values for triangular wave spectra are compared with calculated values.