Video disc player noise reduction circuit

A video disc player for recovering prerecorded signals from a disc record, wherein the prerecorded signals are formed from the composite sum of a first signal modulating a first carrier and a second signal modulating a second carrier, said player comprising:

• signal recovery means cooperating with the disc record for generating an electrical manifestation of the prerecorded signals;
• first circuit means connected to receive said electrical manifestation of the prerecorded signals for selectively demodulating said first carrier, wherein the demodulated signal is subject to inclusion of an undesirable intermodulation distortion manifested as the modulated carrier of the second signal;
• second circuit means connected to receive said electrical manifestations of the prerecorded signals for selectively extracting the second modulated carrier from the composite sum of signals and generating a signal therefrom complementary to the manifested intermodulation distortion;
• and
• means for linearly summing the first demodulated signal containing the intermodulation distortion and the complementary signal, thereby reducing the manifested distortion in the first demodulated signal.

In a video disc player of the type having an asymmetric signal pickup stylus which has a dielectric member asymmetrically supporting a conductive signal pickup electrode, said player including pickup circuits cooperating with the signal pickup electrode for recovering prerecorded information from a disc record, circuitry for extracting baseband video signals from the recovered information, and circuitry for recovering baseband audio signals from modulated sound carrier components of the recovered information;

• said player being subject to sound carrier intermodulation distortion in the baseband video resulting from the interaction of the asymmetric signal pickup stylus with the recorded disc, the improvement comprising:
• frequency selective circuitry responsive to the recovered signal from the pickup circuits for passing the modulated sound carrier substantially to the exclusion of all other signals;
• frequency sensitive circuitry having a predetermined phase response for conditioning said modulated sound carrier to manifest a phase characteristic substantially similar to the sound carrier intermodulation distortion in the baseband video;
• means for conditioning the amplitude of the phase conditioned modulated sound carrier;
• and
• means for linearly subtracting the conditioned modulated sound carrier from the baseband video signal and thereby to substantially cancel the intermodulation distortion therein.