Abstract: In a video disc system, geometric variations are recorded on the surface of the record and are representative of recorded picture and sound information. In a video disc playback apparatus for recovering picture and sound information from such a prerecorded record, a playback stylus is utilized to detect the geometric variations. Sound interference in the video signals may be produced by the non-linear characteristics of the playback stylus. A non-linear aperture correction circuit interposed between the playback stylus and the demodulator circuitry of the playback apparatus effects a substantial control of the intermodulation products.

Abstract: A monitoring circuit for monitoring and measuring the mechanical characteristics of a piezoelectric video disc recording cutterhead takes the form of a bridge network. The motional charge or motional current, which are related to the mechanical characteristics of the cutterhead, is measured by providing signals of a first polarity to one leg of the bridge and signals of a polarity opposite to the first to another leg of the bridge.One leg of the bridge includes the cutterhead and a sensing capacitor connected in series while the other leg includes the sensing capacitor and a balancing capacitor connected in series. When the capacitance value of the balancing capacitor is properly chosen, the voltage drop across the sensing capacitor is proportional to certain mechanical characteristics of the cutterhead (e.g., displacement).

Abstract: Selected fields of a redundant field slow motion video tape reproduced video signal are stored in a memory at a given clock rate and recovered at a lower clock rate that is inversely proportional to the number of times each field is repeated so as to produce a non-redundant video signal of reduced bandwidth. An audio signal is simultaneously reproduced from the tape at a rate less than that at which it was originally recorded and combined with the recovered video signal to produce a composite audio-video signal of reduced bandwidth possessing the full informational content of the original audio and video signals. The composite signal is suitable for application to the cutterhead of a video disc mastering lathe operating at reduced turntable speed whereby full bandwidth master recordings may be made with a cutterhead of lesser bandwidth.

Abstract: Composite color video signals, of the PAL format, are applied to the input of a 1H delay line (exhibiting a 64 microsecond delay, when f.sub.H = 15,625 Hz.). Output of a first comb filter, using additive combination of delay line input and output signals, is applied to a lowpass filter having a cutoff frequency below the lowest PAL color subcarrier sideband frequency. Output of a second comb filter, using subtractive combination of delay line input and output signals, is applied to: (1) a second 1H delay line; (2) a delay device, providing delay correpsonding to a quarter-cycle at the PAL color subcarrier frequency; and (3) a low pass filter having a cutoff frequency below the lowest buried subcarrier sideband frequency. Outputs of two low pass filters are combined to form luminance signal. Outputs of quarter-cycle delay device and second 1H delay device are additively combined to obtain "V" component of PAL signal, and subtractively combined to obtain "U" component thereof.