An Optical Video Disc Player for NTSC Receivers

This paper reports on a team effort to develop an optical player based on a thin flexible disc and the aerodynamic disc stabilizer of Thomson-CSF. The signal is encoded by a method which minimizes the effect of microscopic non-linearities within the disc surface: luminance and chroma together modulate an FM carrier of relatively high frequency. Radial tracking is achieved by a method which keeps the focused laser beam centered on the recorded track, requires no auxiliary beams and permits unusually high track density. Timing errors, caused by eccentricity and distortion of the disc, are suppressed by an electromechanical servo which is combined with the tracking servo. Improved timing error correction opens up an interesting possibility of simplifying the decoder.