Abstract: A logic signal controlled switching video amplifier is disclosed having minimal power dissipation. By utilizing diode and transistor amplifier switching techniques, charging and discharging currents in the video amplifier are controlled. The stray capacitance associated with circuit wiring and cathode ray tube interelectrode capacitance can be rapidly switched without requiring low impedances or high DC current levels in the video amplifier.

Abstract: A synchronous receiver having a reduced pull-in time without requiring a frequency error detection circuit using a differentiator is provided with a voltage-controlled oscillator, a 90.degree. phase shifter which shifts the phase of an output from the voltage controlled oscillator by an angle of 90.degree., first and second synchronous detectors which detect an in-phase component and a quadrature component of a video carrier signal, a phase detector for detecting a phase difference between the video carrier signal and the output of the voltage-controlled oscillator, a first low pass filter for filtering the output of the phase detector, a frequency discriminator for discriminating the frequency of an audio IF signal generated by the first synchronous detector and a second low pass filter for filtering the output of the frequency discriminator.

Abstract: A transversal filter suitable for use in a ghost canceller of television receiver. The amplifiers of the transversal filter employ MOS transistors each loaded by a complementary connection of a P-MOS transistor and an N-MOS transistor constituting a C-MOS transistor pair.

Abstract: Distortion occurring when tan .theta. mapped CIG video is projected onto a ide angle non-tan .theta. display is corrected in both line direction and cross-line direction by varying the propagation time of the pixels within a line to achieve a non-distorted line and by buffering the lines of the display to allow for selective fetching of lines for display in a non-distorted manner. Both pixels and lines are delayed by variable amounts in accordance with their temporal location within a line or frame, respectively.

Abstract: A television receiver of the type capable of displaying standard VHF and UHF televison signals is provided with a single coaxial antenna input terminal. A passive input circuit within the receiver includes two filter sections for separating the VHF and UHF components of a combined VHF-UHF signal applied to the input terminal for application to separate VHF and UHF tuning sections of the receiver. The first filter section, which is located within the UHF tuning section, includes a UHF tuning line for coupling the UHF component to the UHF tuning section. The second filter section, which is located in the VHF filter section, and incorporates elements of the first filter section, enhances the response of the receiver over transition frequencies between the VHF and UHF bands.

Abstract: A double conversion television tuner has first and second mixers and uses both the sum and difference frequency signals from the second mixer. The picture component of the difference frequency is separated from the output of the second mixer using a first filter and then demodulated. A second filter passes the sum frequency signal and the second harmonic of the nominally fixed frequency local oscillator signal applied to the second mixer. A third mixer is coupled to the second filter and mixes the converted sum frequency signal with the second harmonic signal. The audio component of the resulting sound signal is demodulated. Because the sum and difference signals at the output of the second mixer are far apart in frequency, the first and second filters can be easily designed so as not to interact.

Abstract: A ghost reduction circuit for a television receiver incorporating a transversal filter comprises a memory for storing tap gains of tap gain amplifiers constituting part of the filter, a detector for detecting a ghost component as an error signal by comparing a vertical sync signal of the video signal passed through the filter with a reference sync signal, a circuit for converting a differentiated signal derived through differentiation of the error signal into a 3-state digital signal, and a subtractor for correcting the tap gain data stored in the memory in accordance with the digital signal, wherein the ghost component is substantially eliminated from the video signal inputted to the filter by controlling the gains of the tap gain amplifiers in accordance with the corrected memory data.

Abstract: A high brightness mobile video system includes a standby circuit for maintaining a low CRT filament heater circuit current from a battery supply. The standby circuit monitors an input circuit for video signals. On receipt of a video signal, the standby circuit operates a relay to energize a switch mode power supply which further energizes the deflection circuit for the CRT, couples full operating current therefrom to the filament heater circuit, and enables the CRT video drive circuits.

Abstract: A television transmitter for transmitting signals including two sound channels either for dual language or stereophonic sound transmission includes a combining filter 4 having a narrow sound passband. In order to reduce the amplitude modulation of the sound signals caused by the filter characteristic on the frequency modulated sound carriers, the sound carrier signals are amplitude modulated in the opposite sense to that produced by the filter characteristics. This is achieved by passing the modulated sound carrier signals through tuned circuits (L1, C1 and L2, C2) which have their resonant frequencies and Q's appropriately chosen.

Abstract: An AFC circuit for a television receiver capable of unambiguous operation with substantially offset signal frequencies has a response characteristic defined by a positive portion intermediate a pair of substantially equally sized negative portions. The circuit includes a multiplier with an unbalanced coupling between the limiter and the discriminator which has a single adjustable tuned circuit nominally tuned to 45.75 MHz.

Abstract: There is disclosed a VIDEO AUTOMATIC FOCUSSING SYSTEM in which a video signal from the television camera is directed to a band pass filter and then detected to produce a DC signal indicative of the video signal as band limited. The detected signal is directed to the inputs of a negative slope detector and peak detector. The detectors monitor the slope of the video signal to form the basis for controlling the motor to achieve automatic focussing on command.

Abstract: As a signal seeking tuner tunes through a number of channels to locate the next active (useable) channel, the display screen of a television receiver is blanked when the receiver is tuned between channels or to an inactive (unuseable) channel for which video signal information is substantially absent. Superimposed over the blanked screen background is a moveable tuning indicator bar, the position of which indicates the channel to which the receiver is tuned. The blanking of the screen prevents the tuning indication from being obscured by background noise.

Abstract: A switching array comprising low power switching elements for switching high bandwidth pulse encoded signals with minimum distortion. Each switching element comprises an emitter-coupled pair of transistors which are used to switch the pulse encoded signals. The pair of transistors are enabled and disabled by inhibiting the flow of electrical current through the latter. A transistorized switch controls the electrical current in the pair of transistors in response to signals from a control register within the switching array. Since no current is flowing in the pair of transistors when the element is inhibited, the power dissipation approaches zero in the inhibit state resulting in an overall low power dissipation for the switching array since only a small number of elements are normally enabled at any time.

Abstract: A video signal analog-to-digital converter for an image display device comprises a reference signal generator, which can detect variations of the average level of a video signal and generate a variable upper and a variable lower reference potential in accordance with the variations detected. An analog-to-digital converting circuit A/D converts the video signal between present variable upper and lower reference potentials to produce a digital code signal. Brightness control of an LC display panel is done according to the digital code signal.

Abstract: A color television receiver includes a network for automatically limiting excessive kinescope beam currents developed in response to video signal image information, and a white balance control network for automatically controlling the white level drive (gain) characteristics of the kinescope in response to a white drive reference signal applied to the video signal path during given measuring intervals. A control signal developed by the beam current limiter network, otherwise applied to the video signal path, is decoupled from the video signal path during the white level measuring intervals to prevent distortion of the white level control function.