Abstract: Apparatus for automatically controlling the bias of an image reproducing color kinescope in a system incuding a plurality of video driver stages for supplying image representative video signals to respective intensity control electrodes of the electron guns of the kinescope. The output of each driver stage is coupled to an operating supply voltage via a load impedance. The electron gun currents (e.g., cathode currents) are sensed during image blanking intervals of the video signal to provide respective control voltages representative of the electron gun blanking current levels. The control voltages are respectively applied to control the output operating voltage of each driver stage, and thereby the electron gun bias, in a manner to reduce deviations of the blanking current level from a normally expected level. In one embodiment, each driver stage comprises a transistor with a video input base electrode, and a collector output electrode coupled to an electron gun.

Abstract: In a video signal processing system including a clamp for clamping the video signal to a reference level during periodic image blanking intervals of the video signal, and a kinescope for reproducing an image in response to the clamped video signal, apparatus for automatically limiting excessive beam currents drawn by the kinescope. A derived control signal representative of the magnitude of excessive beam currents is applied to the video signal processing path prior to the clamp. The control signal is inhibited during the blanking intervals, and serves to offset the D.C. level of the video signal in the black direction during image trace intervals to reduce the current conduction of the kinescope.

Abstract: A combined phase shift and bandpass filter circuit in a color television receiver including color signal demodulators, and an automatic flesh tone correction network which provides a reference signal for the color demodulators, is disclosed. The circuit comprises an integral bandpass filter and phase shift network coupled between the output of the flesh tone correction network and the reference signal inputs of the demodulators. The circuit filters unwanted frequency components of the reference signal from the flesh correction network, and provides phase shifting of the reference signal as appropriate for proper operation of the demodulators. The circuit exhibits good phase stability, does not require alignment from receiver to receiver, and requires a minimum of connecting terminals to the flesh correction network and color demodulators.

Abstract: A video signal image reproducing system including a video signal processing channel, a kinescope driver for supplying amplified video signals to an image reproducing kinescope, a source of potential to which signals processed by the kinescope driver are referenced, and an adjustable brightness control network which provides a range of brightness reference voltages including a given voltage corresponding to a threshold conduction condition of the kinescope driver. The brightness network is biased from a voltage source from which the signal reference potential is derived. The signal reference potential is coupled to the kinescope driver, and to the brightness network such that the given voltage is produced when the brightness control is at a mid-range setting.

Abstract: Video disc player is switchable between two operating modes: (1) for playback of records of color signals of one scanning standard (15,625 Hz. line frequency; 50 Hz. field frequency) encoded in a buried subcarrier format; (2) for playback of records of color signals of another scanning standard (15,734.26 Hz. line frequency; 59.94 Hz. field frequency) also encoded in a buried subcarrier format, but with a different subcarrier frequency. When operating in mode (1), recovered signals are heterodyned with output of a VCO to up-convert chrominance signal and accompanying color synchronizing component. Control of VCO is effected in accordance with output of a phase detector responding to up-converted color synchronizing component and to reference oscillations, whereby up-converted signals are stabilized against time-base errors.

Abstract: Brightness control apparatus for a video signal image reproducing system including a video signal processing channel, a kinescope driver for supplying video signals to an image reproducing kinescope, and a source of substantially fixed potential to which signals processed by the kinescope driver are referenced. A comparator senses the substantially fixed reference potential and a blanking level which occurs during periodic blanking intervals of the video signal, and provides an output control signal indicative of the voltage difference between the reference potential and the blanking level. The control voltage is applied to the video channel for translating the blanking level in a direction to minimize the voltage difference, to thereby establish the conduction of the kinescope driver during image intervals of the video signal at a level corresponding to a desired image black level condition when such condition is manifested by the video signal.

Abstract: Color encoding format for a color picture information record, and recording apparatus therefor, are disclosed for recording of discs for use with both (1) disc players designed to provide PAL-type outputs for driving PAL-type color television receivers, and (2) disc players designed to provide SECAM-type outputs for driving SECAM-type color television receivers. In players, up-conversion of recovered composite signal precedes comb filtering to separate luminance and chrominance components. Decoding of up-converted chrominance component, to obtain baseband color-difference signal information is followed by remodulation of a carrier pursuant to a desired output format. Comb filter arrangements of U.S. Pat. No. 3,969,757 are used when up-conversion shifts color subcarrier to a frequency in vicinity of PAL subcarrier frequency, but bearing odd integral multiple relationship to half the line frequency.

Abstract: An intercarrier sound system is provided in which a single transistor is used as both the intercarrier sound mixer and a sound I.F. amplifier. The transistor has an input circuit which includes its base-to-emitter junction, and an output circuit including its collector electrode and one of its base and emitter electrodes. Picture and sound carrier signals are applied to the transistor by way of the input circuit and are mixed across the base-to-emitter junction of the transistor. Means are provided at an electrode of the transistor common to the input and output circuits having an impedance which varies inversely with frequency. The variable impedance means causes the amplification provided by the transistor to vary directly with frequency over a band of frequencies including the video signal and the intercarrier sound signal frequencies.

Abstract: A D.C. gain controlled differential amplifier exhibiting balanced operation and a linear gain control response. The amplifier includes input and output emitter coupled transistors and a current source transistor. Input signals are supplied to the base of the input transistor, and a negative feedback network is D.C. coupled from the collector to base of the output transistor. A D.C. gain control voltage varies the conduction of the current source transistor to thereby vary the gain of the emitter coupled transistors. The control voltage is also D.C. coupled to a collector signal output of the output transistor to maintain the output quiescent level substantially constant as the amplifier is gain controlled.

Abstract: A protection circuit for limiting the power dissipation of a video output amplifier when high frequency signals of significant magnitude and with a high density of occurrence (e.g., noise during vacant channel reception) are supplied to the amplifier. The protection circuit includes a control transistor and a sensing network. The sensing network monitors a video signal coupling path to detect the presence of high frequency signals, and derives a voltage representative thereof. The derived voltage is insufficient to render the control transistor operative under normal signal conditions. Under abnormal conditions when significant amounts of high frequency signals with a high density of occurrence are present, the derived voltage is sufficient to render the control transistor operative to develop an output control voltage.

Abstract: Brightness control apparatus for a video signal image reproducing system including a video signal processing channel, a source of reference voltage for establishing a desired level of image brightness, and a keyed comparator circuit. The comparator forms a closed control loop with the signal processing channel, and is keyed during periodic blanking intervals of the video signal to sense the magnitude of the reference voltage and a brightness representative blanking level of the video signal which may vary undesirably. The comparator provides an output control signal indicative of a voltage difference between the reference voltage and the blanking level. The control voltage 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 flat major surface of a disc-shaped substrate (e.g., of glass) is coated with a light-reflective layer (e.g., of aluminum). Overlying the reflective layer is a layer of material (e.g., fluorescein) which is highly absorptive for light of a frequency supplied by a recording laser. The coating parameters are chosen to establish an anti-reflection condition for the coated record blank at the recording light frequency. The light output of the laser, which is intensity modulated in accordance with a signal to be recorded, is focused upon the coated surface of the disc as the disc is rotated. With the peak intensity of the focused light sufficient to cause ablation of the absorptive layer, an information track is formed as a succession of spaced pits in which the reflecting layer is effectively exposed. For playback, light of a constant intensity is focused on the information track as the disc is rotated.

Abstract: A synchronization signal separator circuit is provided for separating the synchronizing signal components of a composite video signal. A composite video signal containing negatively-directed synchronizing pulse components is coupled to one input of a differential amplifier comprising two transistors of one conductivity type, and to the base electrodes of a peak detector charging transistor of opposite conductivity type. The charging transistor charges a peak detecting capacitor to a reference level which establishes the slicing level of the sync separator. The base-to-emitter voltage of the charging transistor offsets the slicing level by one V.sub.be relative to the sync pulse tips, thereby ensuring that the slicing level is offset from the sync tip level. The peak detecting capacitor is coupled to a second input of the differential amplifier, where the slicing level is compared with the composite video signal for separation of the sync pulses.

Abstract: In apparatus for playback of a video disc record bearing chrominance information recorded in "buried subcarrier" format, a comb filter involving subtractive combination of the input and output of a 1H delay line is used to separate chrominance component of recorded composite signal from accompanying luminance signal. Separated chrominance component is subject to demodulation to obtain color difference signals, which are applied to a SECAM modulator to obtain SECAM format signal for delivery to SECAM type color TV receivers. To reduce "cross-color" effects of diagonal luminance components, a second comb filter is interposed between first comb filter and color demodulators. Second comb filter employs 1H delay line with receiving end misterminated by a short circuit termination to obtain reflection effect.

Abstract: A plug-in cartridge designed to mate with an external system via a connector having a plurality of external mating receptacles, and one or more external actuator pins, for engaging the cartridge. The cartridge encloses a printed circuit board with terminals arranged to receive an electrical circuit (e.g., an integrated circuit) susceptible to damage by excessive electrostatic charge. The circuit board includes a plurality of metallic contact areas conductively connected to respective terminals, extending external to the cartridge, and configured to engage the mating receptacles of the connector. The cartridge also includes a protection device comprising a plurality of conductive fingers formed from a common conductive element. The device is arranged such that, when the cartridge and connector are disengaged, the fingers contact associated ones of the contact areas whereby the contact areas and therefore the circuit terminals are connected in common (i.e.

Abstract: A burst gate pulse generating circuit includes a normally saturated transistor responsive to a pulse representative of a horizontal sync component of a video signal which includes a burst interval. The sync pulse is coupled to a base input of the transistor via an RC differentiating network for causing the transistor to operate between saturated and cut-off states, such that a gate pulse produced at the transistor collector output is delayed relative to the sync pulse and substantially coincides with the burst interval. The circuit is arranged so that the sync pulse as coupled via the differentiating network causes the base-emitter junction of the transistor to break down in the reverse direction. The timing of the output gate pulse is therefore substantially independent of the sync pulse amplitude, which can vary undesirably, thereby promoting accurate pulse timing.

Abstract: A circuit is provided for protecting an amplifier from signal overload upon the application of strong signals at the input to the amplifier. A unidirectionally conducting semiconductor device and a capacitor are serially coupled between the input to the amplifier and ground. Means for maintaining a constant voltage is coupled to the junction of the semiconductor device and the capacitor. Upon the application of a strong signal at the input to the amplifier, the semiconductor device conducts current to the junction of the constant voltage means and the capacitor, causing the voltage across the capacitor to increase. The constant voltage means senses this voltage increase, and responds by opposing the voltage increase so as to maintain a substantially constant voltage across the capacitor. The constant voltage at the junction of the semiconductor device and the capacitor maintains the semiconductor device in a low impedance state, thereby attenuating the strong signal at the input to the amplifier.

Abstract: A television synchronization signal generator circuit is provided for generating television synchronization, blanking, and drive signals. The sync generator is programmable to provide synchronization signals in the PAL, SECAM, NTSC, and PAL-M standards at the appropriate 525 or 625 line rate. A synchronous horizontal counter is used to divide clock pulses having a frequency of 134 times the horizontal line frequency down to the horizontal line frequency. A vertical counter divides a phase advanced signal having a frequency of twice the horizontal line frequency by 525 or 625 to arrive at the vertical field rate. Logic gates decode the horizontal and vertical counter output signals to condition output signal flip-flops which are retimed by the input clock pulses to eliminate phase delays between the clock pulses and the output signals. Reset inputs are provided for synchronizing the sync generator to an external signal source.

Abstract: Apparatus in a video signal processing system for improving the quality of a color image reproduced by a color kinescope in response to chrominance and luminance components of the video signal, the chrominance signal being subject to phase transitions likely to generate chrominance subcarrier components sufficient to contaminate the luminance signal. Chrominance signals delayed by an amount corresponding to an interval during which the phase transitions can occur are supplied to inputs of a signal multiplier, which provides an output signal indicating the presence of chrominance phase transitions. The multiplier output signal is utilized for controlling the luminance signal processing channel to suppress the sideband signals, thereby also suppressing objectionable effects of the sideband signals otherwise visible in a reproduced image.

Abstract: Apparatus in a video signal processing system for improving the quality of a reproduced color image by reducing visible "cross-color" interference caused when high frequency luminance signals occur within the passband of the chrominance component of the video signal. Video signals within the chrominance passband are sensed by a signal multiplier responsive to the video signal and to the video signal delayed by a given amount. The amount of delay corresponds to an interval during which rapid luminance transitions capable of producing the high frequency signals within the chrominance passband can occur. The multiplier generates a control signal indicative of the presence of the luminance transitions, which is then utilized for controlling the chrominance signal processing channel such that objectionable cross-color effects otherwise visible in a reproduced image are reduced or eliminated.