Rca Inc.

Hugh F Sutherland, Ii

David W Luz

Donald Henry Willis

Peter E Haferl

Gary T Osborne

George C Waybright

James A McDonald

A vertical deflection amplifier of a video display apparatus includes first and second transistor amplifier output stages arranged in a totem-pole, push-pull configuration. A vertical deflection winding is coupled to the output stages at a deflection amplifier output terminal. An S-capacitor is coupled to the deflection winding at a second terminal remote from the output terminal. A source of deflection rate signals is coupled to the deflection amplifier for generating a deflection current in the deflection winding. A base current generating circuit is coupled to one of the transistor amplifier output stages for providing base current thereto. The S-capacitor voltage is applied to the base current generating circuit for enabling conduction of base current in the one amplifier output stage. When the video display apparatus is first turned on, the initially discharged S-capacitor is slowly charged from a DC voltage supply to delay generation of vertical deflection past completion of picture tube degaussing.

Vertical deflection circuit

An auxiliary kinescope beam current limiter in a television receiver includes a control circuit responsive to a sensed signal representative of the combined instantaneous magnitudes of plural color video signals. The control circuit includes, in the order named, a first low pass filter, a first peak detector, a second low pass filter, and a second peak detector which provides a control signal to video signal processing circuits for limiting the amplitudes of the plural color video signals when a given amplitude threshold value is sensed as having been exceeded. The auxiliary beam current limiter is able to prevent warping or blistering of a shadow mask in a color kinescope due to scenes having a high beam current in, for example, an area equal to or greater than five to ten percent of the display screen area of the kinescope in both the horizontal and vertical directions.

Auxiliary kinescope beam current limiter with plural cascaded low pass

Line and field deflection circuits generate line and field deflection currents in respective line and field deflection windings to scan a raster on the phosphor screen of a square-planar picture tube having an aspherical faceplate. The asphericity of the faceplate subjects the scanned raster to gullwing distortion. A gullwing distortion correction circuit is responsive to signals repeating at line and field rates, respectively, for modulating the field deflection current during a line deflection period within the field deflection trace interval in a manner that corrects gullwing distortion of a corresponding raster scan line.

Gullwing distortion corrected deflection circuitry for a square-planar

A high voltage generator develops an ultor voltage to accelerate an electron beam of a picture tube. The high voltage generator draws a resupply current in accordance with beam current loading by the picture tube. The deflection circuitry generates line and field deflection currents in respective line and field deflection windings to enable the electron beam to scan a raster. A diode modulator, including a differential amplifier input stage and an emitter-follower output stage, modulates the amplitude of the line deflection current to provide side pincushion correction. The voltage at a high voltage resupply current terminal of the high voltage generator is coupled in a nonlinear manner to the differential amplifier for nonlinearly modulating the amplitude of the line deflection current in accordance with beam current loading.

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Indianapolis, IN, United States of America

Hugh F Sutherland, Ii