Abstract: A deflection switch of a horizontal deflection circuit is coupled to a retrace resonant circuit that includes a horizontal deflection winding and a first retrace capacitance. A flyback transformer primary winding is coupled to a junction terminal of the deflection switch and the resonance circuit. An East-West modulation current is generated by a bidirectional second switch having a conduction time that is phase modulated during horizontal retrace at a vertical rate in a parabolic manner. The second switch is coupled in series with the first switch during the entire trace interval. To prevent an over-current condition when the current in the second switch exceeds a predetermined first level, the second switch is turned off and interrupts the flow of current through the deflection switch.

Abstract: An auxiliary video input terminal (S-terminal) couples luminance and chrominance input signals to respective inputs of peaking circuits in the display processor of a receiver. The chrominance input signal is subjected to pre-distortion (de-peaking) to correct for sideband amplitude distortion in the chrominance peaking filter of the receiver thereby preventing color distortion in displayed images. The luminance signal is subjected to additional peaking at a frequency greater than the characteristic peaking frequency of the luminance peaking filter thereby enhancing the sharpness of wideband luminance input signals displayed by the receiver.

Abstract: In the context of a video signal raster mapper, apparatus is disclosed to facilitate time compression or expansion by developing an auxiliary signal (DX) representing a fractional position of output pixel samples between input pixel samples. A multiplexer selectively applies values from two registers to an accumulator for controlling the accumulator value in a manner appropriate for compression or expansion.

Abstract: An auxiliary video input terminal (S-terminal) couples luminance and chrominance input signals to respective inputs of peaking circuits in the display processor of a receiver. The chrominance input signal is subjected to pre-distortion (de-peaking) to correct for sideband amplitude distortion in the chrominance peaking filter of the receiver thereby preventing color distortion in displayed images. The luminance signal is subjected to additional peaking at a frequency greater than the characteristic peaking frequency of the luminance peaking filter thereby enhancing the sharpness of wideband luminance input signals displayed by the receiver.

Abstract: In a color television receiver having first and second chroma amplifiers, a chroma overload detector uses a differential amplifier for peak detection of a chrominance signal over a predetermined threshold level, and in response thereto, for generating a control signal and applying it to the second chroma amplifier to control the gain of the amplifier.

Abstract: Comb filter apparatus for comb filtering NTSC or PAL video signals includes sampling circuitry to sample the video signal at 45 degrees relative to the I,Q or U,V axes. The sampled signal is coupled to delay circuitry arranged to concurrently provide video samples from three successive horizontal lines, designated top, middle and bottom. The video samples from the middle line are combined with samples alternately selected from the top and bottom lines to provide a comb filtered signal.

Abstract: A dual power source output amplifier comprises at least one pair of first and second input voltage sources of like polarity, operating at low and high voltage magnitude levels respectively relative to one another, and selectively operably coupled to an output stage for driving a load, for example a convergence yoke coil, in low and high voltage modes respectively. The first voltage input source is coupled to the output stage in the low voltage mode. A circuit for directly sensing the output voltage couples a biasing voltage level to the output signal for generating a high voltage demand control signal which varies directly with the output voltage. A switchable voltage regulator couples regulated high voltage from the second voltage input source to the output stage in the high voltage mode, responsive to the high voltage demand control signal. The output stage operates substantially linearly in both voltage modes.

Abstract: A combined RFI filter and low pass filter includes two sections, both of which serve as both radio frequency interference filters and low pass filters, or dc integrators. Both sections have substantially equal time constants and employ non-polarized capacitors.

Abstract: A tuning system is provided which allows a user to enter text labels associated with respective channels or television programs to be tuned so that, thereafter, a channel or program to be tuned may be selected by the user by entering its label. Scheduling of television programs by label is also provided by storing time-related data as well as channel-related data and associating these data for each television program with a user-entered label.

Abstract: The present invention is for a highpass input circuit for a television receiver having an additional trap at a predetermined frequency, e.g. CB frequencies. A M derived constant K high pass filter having an intermediate pi configured filter section is provided with an additional inductor in the shunt leg of the pi section for resonating with the bridge capacitance of the pi section and forming an additional trap at the predetermined frequency. The additional inductor is physically formed by an electrically conductive path etched on a printed circuit board.

Abstract: An improved method of making a color picture tube electron gun includes the selection and assembly of a plurality of cathodes and a plurality of electrodes longitudinally spaced from the cathodes. The improvement comprises at least three additional steps. First, the amount and direction of electron beam misconvergence at the tube screen, as caused by the thermal expansion of each individual electrode during electron gun warmup, is determined. A first group of electrodes will cause misconvergence in a first direction, and a second group of electrodes will cause misconvergence in a second direction. Second, the individual contributions of the electrodes to misconvergence during tube warmup are summed. The net effect of thermal expansion of the entire electron gun is a misconvergence in the first direction.

Abstract: The present invention provides an improvement in color picture tubes including an evacuated glass envelope having a rectangular faceplate panel. The panel includes a shadow mask assembly mounted therein by support means located at peripherally spaced positions within the panel. The support means at each of the spaced positions includes a stud attached to the glass envelope, a spring and a plate. The spring has an aperture therein that engages the stud. The spring is attached to the plate, and the plate is welded to the mask assembly. The improvement comprises the plate being welded to the mask assembly at only one location. This location is on a line, perpendicular to the plate, that passes through the center of the aperture in the spring.

Abstract: In a television receiver, a magnetic field compensator of a horizontal component of the earth's magnetic field includes a fluxgate magnetometer having a pair of sensing windings for generating first and second sensing signals representative of corresponding components of the horizontal component of the earth's magnetic field. The sensing signals generate current in a pair of substantially planar coils disposed in a non-parallel vertical configuration on the rear periphery of a cathode ray tube. The currents in the coils produce a magnetic field that compensates or neutralizes the effect of the horizontal component of the earth's magnetic field on the electron beam in the cathode ray tube. Whenever the position of the receiver is changed, rotationally or geographically, the current in the coils is automatically adjusted to provide automatic neutralization.

Abstract: A contrast control circuit develops a video gain control signal for continuously varying the video gain of a video signal to adjust the contrast of the video signal and limit beam current. The contrast control circuit may comprise an auto contrast control responsive to video signal peaks, a contrast limiter responsive to a beam current control signal related to average picture intensity and a manual control. A brightness modulator is also responsive to the contrast control signal for continuously adjusting the brightness of the video signal inversely with the contrast. The brightness modulation is especially useful as part of a pix-in-pix video control circuit, further comprising video sources for first and second video signals and a selector for alternatively feeding the first and second video signals to a video amplifier to form a primary picture with an inset secondary picture.

Abstract: A temperature compensation network for an integrated circuit amplifier in a television receiver includes a thermistor mounted physically adjacent to, and electrically connected in parallel with the brightness control potentiometer, to the brightness control terminal of the integrated circuit. By mounting the thermistor in close proximity to the integrated circuit to be controlled, the thermistor is able to compensate for both self-heating of the integrated circuit and ambient temperature variations.

Abstract: A memory retention system for an electronic apparatus having several logic devices driven by a common oscillator includes a capacitor for retaining a voltage on at least one of the logic devices and means for stopping the oscillator during a power failure. The logic devices have respective oscillator input terminals which are connected together and to the input terminal of the oscillator rather than to the output terminal of the oscillator to reduce current drain from the capacitor.

Abstract: In a switch mode power supply, a first switching transistor is coupled to a primary winding of an isolation transformer. A second switching transistor periodically applies a low impedance across a second winding of the transformer that is coupled to an oscillator for synchronizing the oscillator to the horizontal frequency. A third winding of the transformer is coupled via a switching diode to a capacitor of a control circuit for developing a DC control voltage in the capacitor that varies in accordance with a supply voltage B+. The control voltage is applied via the transformer to a pulse width modulator that is responsive to the oscillator output signal for producing a pulse-width modulated control signal. The control signal is applied to a mains coupled chopper transistor for generating and regulating the supply voltage B+ in accordance with the pulse width modulation of the control signal.

Abstract: A high voltage regulator circuit for maintaining the ultor voltage applied to a picture tube of a television receiver apparatus provides an auxiliary voltage signal for compensation of variations in the ultor voltage caused by variations in the beam current. An improved phase control circuit controls the phase position of the pulses of the auxiliary voltage signal so that they lag with only the leading parts thereof overlapping the retrace voltage signal pulses, in order to prevent the introduction of fluctuations in the ultor voltage due to secondary ringing.

Abstract: A rectangular color picture tube of the shadow mask type includes an improved mask-frame assembly and support therefor. The frame has two substantially perpendicular flanges, a first flange and a second flange. The first flange extends from the second flange away from the screen of the tube. The second flange extends from the first flange toward the shadow mask. The second flange includes peripherally spaced tabs extending therefrom. The shadow mask is telescoped into the frame and is attached to the tabs. In a preferred embodiment, the corners of the frame are truncated. Springs are interconnected to each truncated corner of the frame to support the mask-frame assembly within the tube.

Abstract: In a switch mode power supply, a first switching transistor is coupled to a primary winding of an isolation transformer. A secondary winding of the transformer is coupled via a switching diode to a capacitor of a control circuit for developing a DC control voltage in the capacitor. The DC level of the control voltage varies in accordance with a supply voltage B+. A change in voltage B+ produces a corresponding, greater change in the control voltage. The control voltage is applied to the transformer when the diode is conducting for producing a pulse-width modulated control signal. The control signal is applied to a mains coupled chopper transistor for generating and regulating the supply voltage B+ in accordance with the pulse width modulation of the control signal.