Rca Inc.

Lucent Technologies Inc.

At+t Corp.

Jack E James

James H Wharton

Richard C Palmer

Jerome Barth Halter

Gunter John

Richard M Castle

Stephen Gratzer McWilliams

Byron Lynn Johnson

Ronald Lee Katz

John E Economou

Edward J Freeman

Michael Wyndham Heller

John G Pecorari

Apparatus for interdicting television channels of a cable television system comprises a plurality of oscillators dedicated to jamming the audio portion of television channels to be interdicted, and a further plurality of different oscillators dedicated to jamming the video portion of television channels to be interdicted. The number of jamming oscillators for jamming the audio is less than or equal to the number of jamming oscillators for jamming the video. The hopping rate for video jamming is greatly in excess of the hopping rate for audio jamming. On the other hand, the dwell time for audio jamming is greatly in excess of the dwell time for video jamming. At least two levels of jamming effectiveness of both audio and video portions can be addressably controlled from the headend of a system including such interdiction apparatus. If shared oscillators according to prior art techniques are used to jam both audio and video, this form of jamming engine may be selectively actuated in preference to or as an alternative for a jamming engine comprising both an audio jamming oscillator and a video jamming oscillator.

Method and apparatus for interdicting cable television channels

A system for reducing bandwidth of video signals. Ordinarily, an NTSC (National Television Standards Committee) video signal has (a) a bandwidth of 6.0 MHz, (b) chrominance and luminance carriers separated by about 3.58 MHz, and (c) an audio carrier located at the upper end of the 6.0 MHz bandwidth. The invention reduces the separation between chrominance and luminance carriers to about 2.15 MHz, and decreases the bandwidth to about 4.0 MHz. In addition, the invention moves the audio carrier outside the 4.0-MHz bandwidth. The invention allows multiple channels, of 4.0 MHz bandwidth each, to be placed adjacent each other in a cable television spectrum, and the audio signals of the channels to be placed together, at the upper end of the spectrum, outside the range allocated to the video information. A larger number of channels is obtained than would otherwise be available, because the upper end of the spectrum is not suitable for carrying video information, but will handle audio information.

Method and apparatus for reduced-bandwidth transmission of television

A video disc record of the constant angular velocity type (CAV) includes a spiral groove of constant pitch formed in a band on a surface thereof. The groove has a substantially constant nominal vertical dimension and vertical displacements which taper monotonically from an outer radius of the band to an inner radius. One component of the vertical displacement of the groove conveys an FM carrier wave of constant amplitude and relatively high frequency representative of picture information. A second component of the vertical displacement conveys one or more lower frequency FM carrier waves representative of sound information. The amplitude of the second component varies monotonically as a function of the groove radius within the record band to provide a disc having an improved audio FM carrier-to-noise ratio with no substantial perceptible increase in undesirable sound beat effects in images displayed when the disc is played. A mastering system exemplary of the method of forming the grooved disc includes variable gain units in an audio FM carrier wave processing path of the system.

Disc record with tapered groove

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 from the memory at a clock rate inversely proportional to the number of times each field is repeated so as to produce a non-redundant video output signal of reduced bandwidth yet processing the full informational content of the original video signal. The original signal normally exhibits an ordered color field sequence but is subject to anomalous variations from time to time which causes anomalous variation of the chrominance-burst phase relationship of the video output signal. A detector, responsive to a change of a parameter of the video input signal, detects the anomalous variations of the chrominance-burst phase relationship and produces a control signal that is applied to a circuit which effectively reverses the phase relationship of the chrominance and color burst components of the video output signal of the memory when the control signal is present.

Video disc slow down processor with reverse color detector/corrector

A composite video signal is separated into luminance and chrominance components which are processed in separate channels having transfer functions which differ in terms of frequency response and large signal amplitude response. The luminance channel subjects the luminance signal to high frequency preemphasis and to hard limiting or clipping at predetermined fixed levels. The chrominance channel exhibits a substantially uniform amplitude response and a variable compression characteristic dependent upon the chrominance signal level, a sum of chrominance and processed luminance signals or a composite output signal formed by a sum of processed chrominance and processed luminance signals. The composite signal is suitable for application to a picture carrier frequency modulator whereby an FM signal is produced suitable for video disc or tape recording and in which a tendency for luminance-chrominance crosstalk or interference is minimized.

Video processor employing variable amplitude compression of the

The output frequency of a variable frequency oscillator is compared with that of a reference frequency source by means of a phase detector and the resultant error signal is integrated and applied as a negative feedback signal to the input of the oscillator whereby drift of the oscillator output frequency is minimized. Deviation, modulation index, dynamic stability and linearity are enhanced by means of a pulse generator that is synchronized with a modulating input signal supplied to the oscillator for supplying a keying signal to the phase detector during a portion of each cycle of the modulating input signal.

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Indianapolis, IN, United States of America

Jack E James