Zenith Radio Corporation

Alain H d'Hautecourt

Ronald B Lee

Wayne E Bretl

George J Tzakis

An AC signal processing circuit fabricated on a single integrated circuit chip used in a television receiver is both defeated and the DC level characterizing its output terminal is controlled in response to a manually operable switch communicating with a single input pin of the chip. A control circuit comprising a pair of differential amplifiers fabricated on the chip is responsive to the switch for enabling the AC signal processing circuit or, alternatively, for inhibiting the circuit while simultaneously causing its output to assume a controlled DC level.

Noise processor defeat switch

A television receiver includes an interface circuit enabling the production of on-screen displays of alpha-numeric type information in a selected color. The interface circuit is responsive to a blanking signal for reducing the red, green and blue video signals developed in response to a received NTSC color television signal below the blanking level of the television receiver. A digital signal representing selected alpha-numeric type information is coupled from a character generator to the interface circuit for increasing the potential at one or more of the electron guns of the receiver for producing a corresponding on-screen display in a selected color.

On screen color display

A luminance signal processing circuit for a television receiver comprises means for separating a full bandwidth luminance signal into a low pass component and first and second derivative components of the low pass component. A differential amplifier is responsive to the component voltage signals for developing first and second current mode signals representing in phase and 180.degree. out of phase combinations of the low pass and second derivative components. The levels of the second derivative components of the first and second current mode signals are selectively adjusted by a peaking signal processor for developing related third and fourth current mode signals whose amplitudes are also selectively adjusted by a picture signal processor for developing an output luminance voltage having selectively controlled contrast and peaking components. A peak white limiter is responsive to white going portions of the second derivative components of the third and fourth current mode signals for automatically causing a corresponding reduction in the level of the output luminance voltage. Finally, a single supply of DC potential is coupled to the picture signal processor for supplying the bias energy from which the first, second, third and fourth current mode signals are derived.

Growing community of inventors

Prospect Heights, IL, United States of America

Alain H d'Hautecourt