Rca Inc.

General Electric Company

Frank B Lang

Charles Benjamin Dieterich

Michael D Ross

James J Gibson

Jon K Clemens

John J Gibson

Theodor M Wagner

The present invention is directed to an improved solution to the problem of interference in the picture displayed by a standard NTSC receiver that results from a received television signal that includes a quadrature-amplitude modulated additional-information constituent passing through the Nyquist filter of the standard receiver (this additional-informaton constituent being intended for use only by wide-screen and/or extended-definition television receivers). This solution, in accordance with each of several different embodiments, employs means at the transmitter that includes frequency-dependent attenuation means operating at baseband frequencies to modify the relative amplitudes of each frequency component of the lower and upper sidebands of the transmitted television signal that defines the additional-information constituent in a manner to compensate for the attenuation characteristics of the Nyquist filter of a standard NTSC receiver.

Interference reduction for extra-spectrum, compatible television system

A high voltage holddown circuit is used in a television receiver which derives high voltage potential from horizontal flyback pulses and which provides horizontal rate signals to the horizontal deflection circuit via a high frequency countdown arrangement. The holddown circuit operates by changing the divider modulus of the countdown circuitry during an overvoltage condition which reduces the amplitude of the flyback pulses and consequently reduces the high voltage.

Television receiver high voltage protection circuit

The present invention describes non-linear circuitry for reducing intermodulation distortion occurring in signals recovered from a disc record. The non-linear circuit generates complementary signals in a diode modulator for cancelling the undesired distortion components of the recovered signal. A synchronous detector in a servo loop with the non-linear circuit samples the distortion component of the resultant baseband video signal and applies bias to condition the non-linear circuit to further reduce the distortion-components. A reference signal for the detector is derived from the sound components of the recovered signal.

Adaptive distortion elimination circuitry for a video disc player

Under certain conditions a video disc player can be responsive to externally applied interference signals to provide a defect in the display of the information recovered from the disc. Apparatus is provided between the pickup circuits and the normal defect compensation apparatus of the player to detect the presence of the external signals and to activate the normal defect compensation apparatus when the external signals are of a relatively high frequency and above a certain amplitude level.

Video disc player with RFI reduction circuit

Under certain conditions a video disc player can be responsive to externally applied interference signals to provide a defect in the display of the information recovered from the disc. Apparatus is provided between the pickup circuits and the normal defect compensation apparatus of the player to detect the presence of the external signals and to activate the normal defect compensation apparatus when the external signals are of a relatively high frequency and above a variable offset or threshold level. The threshold is made to vary as a function of the amplitude of the signal provided at the output of the pickup circuits.

Video disc player with variable offset RFI reduction circuit

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.

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Princeton Junction, NJ, United States of America

Frank B Lang