Abstract: In a video signal processing system, apparatus for limiting excessive peak and average beam currents demanded by a kinescope in response to image representative video signals. A control signal derived by a sensing circuit in response to excessive beam current is applied to the kinescope in a manner to limit excessive beam currents above a threshold level. The sensing circuit includes a capacitor arranged with a conductive diode to form an average responding filter such that the sensing circuit derives a control voltage representative of excessive average beam current in a first beam current limiting mode. In a second beam limiting mode, when beam current exceeds a predetermined level, the diode is rendered nonconductive and the capacitor is decoupled for average detection purposes. In this mode, the control signal is free to vary in accordance with rapid variations in peak beam current.

Abstract: A method of manufacturing a stylus by modifying a square post shaped diamond element is disclosed. A tip having a conical surface is ground at one end of the diamond element. An electrode bearing surface is formed in the region of the tip such that the angle subtended by the electrode bearing surface with the axis of the element is not less than the angle included between the conical surface and the axis. A record engaging surface substantially orthogonal to the electrode bearing surface is formed in the tip region such that the two surfaces intersect along a line substantially perpendicular to the stylus axis. A thin layer of conductive material is deposited on the electrode bearing surface to form a stylus electrode.

Abstract: A novel pickup stylus includes a tapered diamond support element having a plurality of conical portions in the region of its tip, which conical portions have a common axis. Two of the conical portions are separated by an electrode bearing surface. The angle of inclination of the electrode bearing surface with the stylus axis is not less than the angle included between the conical portions and the stylus axis. A record engaging surface is provided in the tip region substantially orthogonal to the electrode bearing surface such that the two surfaces intersect each other along a line substantially perpendicular to the stylus axis. The perpendicular line forms the base of a stylus footprint disposed in the plane of the record engaging surface.

Abstract: A protective cover for a video disc comprises an enclosure having an edge opening in communication with a record enclosing cavity and a record retaining member slidably mounted within the cavity for to-and-fro movement therein. The record retaining member includes a spine portion and an annular portion having an opening. The opening in the annular portion substantially encircles an enclosed record such that to-and-fro movement of the record retaining member is transmitted to the enclosed record. The spine portion substantially extends into the edge opening of the enclosure when it is fully inserted therein. The spine portion has a record extracting member receiving hole that is accessible in a direction substantially parallel to the direction of the to-and-fro movement of the record retaining member.

Abstract: In a color television receiver luminance channel, transistor amplifier stage develops respective versions of input video signals across load resistors in collector and emitter circuits. Capacitor links collector to stage's output terminal, and parallel combination of inductor and resistor links emitter to output terminal. Parameter values are chosen to cause stage to provide delay-versus-frequency characteristic compensatory for delay distortion introduced by receiver's IF amplifier. Use of variable resistor as collector load resistor provides facility for adjustable peaking of luminance channel's amplitude-versus-frequency characteristic while maintaining delay distortion compensation effect.

Abstract: In a PAL color television system for processing a color signal including burst and chrominance components alternating in phase at the image line scanning rate, identification and control circuitry for rapidly correcting an incorrect mode of line to line color demodulator switching. A bistable circuit generates timing signals for controlling line by line switching of a selected color demodulator (e.g., R-Y). An identification signal representative of an incorrect line switching mode is derived from information contained in the burst component, and serves to reset the bistable circuit such that timing signals corresponding to a correct switching mode are produced. The identification signal is derived by a filter circuit exhibiting a fast response time relative to the line scanning time, in order to rapidly respond to the switching mode identification information occurring at the line rate and thereby rapidly restore the correct demodulator switching mode.

Abstract: Apparatus for forming a color TV signal of a SECAM type from a pair of correlated color-difference signals (R-Y; B-Y) includes a pair of transistors disposed in a differential amplifier configuration, with a constant current source coupled to interconnected emitters, and a load impedance coupled to one collector. Pre-emphasized B-Y signal is applied to first transistor base during alternate line scanning intervals; pre-emphasized R-Y signal is applied to second transistor base during intervening line scanning intervals. Electronic switches control bias application to transistor bases so that (a) during horizontal sync intervals bases are equally biased; (b) during alternate line scanning intervals (and preceding "backporch" intervals) base bias of second transistor is elevated relative to the first; and (c) during intervening line scanning intervals (and preceding "backporch" intervals) base bias of first transistor is elevated relative to the second.

Abstract: Brightness control apparatus in a video system employing a sample and hold circuit including a charge storage capacitor. The sample and hold circuit forms a closed control loop with a signal processing channel, and is keyed during periodic blanking intervals of the video signal to sample the magnitude of a reference voltage and a brightness representative blanking level of the video signal. The sample and hold circuit provides an output control signal indicative of the voltage difference between the reference voltage and the blanking level. The control signal is applied to the signal channel for translating the blanking level in a direction to minimize the voltage difference, so that a desired relationship between the reference voltage and the blanking level is preserved.

Abstract: A comb filter arrangement for processing video signals containing frequency interleaved image representative luminance and chrominance components provides improved color definition of reproduced images in the presence of chrominance components of adjacent horizontal image lines which differ perceptibly from each other in amplitude or phase. The comb filter comprises at least one signal delay element arranged to provide a delay equal to one horizontal line scanning interval, at least one gain controllable element and sum and difference networks for combining delayed and undelayed video signals to provide relatively separated luminance and chrominance components. A control network coupled to the comb filter provides a control signal representative of the magnitude of signal components within the chrominance signal frequency range for controlling the gain of the gain controllable element.

Abstract: Apparatus for automatically limiting excess beam current conduction of a kinescope in a television signal processing and reproducing system. A control network including an active device (e.g., a transistor) provides a control signal representative of the magnitude of beam current conduction when above a predetermined threshold level. A dynamic operating control range of the active device is determined independent of a threshold control level of the active device by means of a degenerative direct current feedback network associated with the active device. The control signal is coupled to the kinescope for opposing excess current conduction thereof.

Abstract: An image brightness control arrangement for a color video signal processing system including a plurality of amplifiers each responsive to luminance and separate color difference signals for developing color representative output signals. A brightness control (e.g., a potentiometer) also is included for varying a brightness determinative D.C. level of the luminance signal. A locally generated periodic keying signal, occurring during periodic image blanking intervals of the video signal and of a magnitude which may vary undesirably, is coupled to each of the amplifiers for establishing a reference level for the color difference signals, as described in U.S. Pat. No. 3,970,895. A derived signal indicative of the magnitude of the keying signal is coupled to the brightness control for establishing a brightness control range thereof.

Abstract: In a PAL color television signal receiver including a color demodulator, a source of first timing signals for determining the line by line switching of the color demodulator, and a source of second timing signals coincident with the burst interval of the color signal, a circuit for identifying an incorrect mode of line by line color demodulator switching. A signal representative of the periodic, alternating phase burst component of the color signal is sampled every other image line to derive an identification signal representative of the timing of the burst component. The identification signal is utilized to alter the operation of the source of timing signals to produce timing signals corresponding to a correct switching mode.

Abstract: An arrangement of charge transfer devices comprising a main signal transfer path defined by first and second sets of charge transfer electrodes, and an auxiliary path independent of the main path including a predetermined number of electrodes. Capacitances are respectively associated with the electrodes forming the first and second sets of electrodes of the main path, and with the electrodes of the auxiliary path. The electrodes of the auxiliary path are connected to the one of the sets of electrodes of the main channel to establish a desired relationship (e.g., balance) between the capacitances of the first and second sets of electrodes.

Abstract: A beam current limiter for a kinescope responsive to video signals coupled to the kinescope via a video signal transmission channel comprises means for providing a control signal representative of the magnitude of kinescope beam current above a predetermined level. The control signal is related to the amount by which the beam current exceeds the predetermined level. When beam current exceeds the predetermined level by an amount within a first range of beam current, the control signal is coupled to the signal transmission channel to vary the peak amplitude of the video signal to inhibit beam current above the predetermined level. When beam current exceeds the predetermined level by a relatively greater amount within a second range of beam current, the control signal is coupled to the signal transmission channel to vary both the peak amplitude and the D.C. level of the video signal to inhibit beam current above the predetermined level.

Abstract: A service switch in a color television receiver for simulating quiescent signal conditions to permit set-up adjustment of a color image reproducing kinescope responsive to luminance and chrominance signals processed by luminance and chrominance channels of the receiver. Separate, adjustable image brightness and contrast control networks are coupled to the luminance channel for respectively varying a D.C. level and peak-to-peak amplitude of the luminance signal. The switch has "normal" and "service" positions and is coupled to the chrominance channel, brightness and contrast networks, and a vertical deflection circuit of the receiver. In the "service" position, the switch renders the chrominance channel inoperative to process the chrominance signal, and disables vertical scanning of the kinescope. The switch also causes the brightness and contrast networks to establish predetermined values of the D.C.

Abstract: Video disc play/record apparatus includes a turntable driven by a uni-directional DC motor, a speed loop for controlling motor rotation responsively to horizontal sync signal and a position loop for controlling the rotational phase of the turntable responsively to a frame sync signal. The speed loop comprises a motor driven tachometer whose output is stabilized by a phase locked loop about a nominal frequency. A phase and frequency difference detector, responsive to the phase locked loop output and the horizontal sync signal, provides a driving voltage to power amplifiers coupled to the motor. The position loop includes means cooperating with the speed loop to regulate the turntable phase of rotation responsively to the phase difference between the outputs of a turntable tachometer and a frame and vertical sync signal source.

Abstract: Information processing system, for use with a source of carrier waves modulated with audio information, includes in respective audio channels a demodulator and for recovery of the audio information and track-and-hold amplifiers. Separate circuits are provided for detecting carrier drop-outs and impulse noise occurrences. The output of the detecting circuits is utilized to control the operation of the track-and-hold amplifiers to effect a masking of these occurrences. Signal de-emphasis is accomplished in each channel by means of two separate filters respectively arranged to operate on the input and output signal of the track-and-hold amplifier to minimize noise input to the track-and-hold amplifier.

Abstract: A wide bandwidth video amplifier suitable for driving a kinescope of a television receiver exhibits suppressed radio frequency (RF) harmonic radiation. The amplifier includes a transistor having a nonlinear conduction characteristic in a region of low current conduction. An input circuit including a source of video signals is coupled to a base electrode of the transistor, and output signals are provided from a collector output circuit of the transistor. Degenerative direct current feedback is provided from the output circuit to the input circuit. Undesired RF harmonics produced by dynamic operation of the transistor in a region of low current conduction is suppressed in a first instance by a nonlinear conduction device (e.g., a forward biased diode) arranged to provide degenerative emitter feedback for the transistor during low current conduction. Harmonic radiation is suppressed in a second instance by a low pass filter interposed between the input circuit and the base electrode of the transistor.

Abstract: A service switch to permit set-up adjustment of a color image reproducing kinescope in a color television receiver. The receiver comprises a horizontal deflection circuit for providing a periodic horizontal deflection signal having a frequency synchronized by a sync signal derived from a composite color video signal, and means for deriving a receiver operating voltage from the periodic signal of a magnitude dependent upon the frequency of the periodic signal. The switch has "normal" and "service" positions, and is coupled to respective direct voltage control terminals of luminance and chrominance channels and a vertical deflection circuit of the receiver. In the "service" position, the switch renders the luminance and chrominance channels inoperative to couple signals, and vertical scanning is disabled, to permit set-up adjustment of the kinescope.

Abstract: A method of forming a recording disc having a smooth groove suitable for recording video information from a disc having irregularities along the peaks between adjacent groove convolutions by replicating the grooved disc to produce a negative reproduction of the groove and applying an excess of deformable or removable material such as electron beam sensitive material to the surface of the replicated disc while rotating the disc rapidly only long enough to drive off the excess material and allowing the remaining material to dry, partially filling the groove and providing a continuous coating over the wall and valley portions thereof.