FREQUENCY-MODULATION IN VIDEO TAPE-RECORDERS

Essentially all consumer video tape recorders use frequency modulation for the luminance component of the video signal and demodulation is p erformed by zero crossing detection. Distortion-free video requires th at the zero crossings of the frequency modulation waveforms be preserv ed exactly, In this paper, the complete set of mathematical conditions for zero-crossing preservation is derived from first principles. Whil e some of these conditions have been discussed previously, the complet e set derived here is believed to be novel.