North American Philips Consumer Electronics Corp.

Magnavox Consumer Electronics Company

Patrick M Rafter

James E Hitchcock

Donald B Wolter

An interface circuit for translating digital signals signifying colors in any of various color formats into analog signals for controlling respective primary colors of a display monitor operating in a standard R, G, B primary color format. The circuit adds a control bit to each digital signal identifying the color format of the signal, and each of the colors signified by respective digital signals are identified by digital words corresponding thereto stored in a digital memory. The bits of each stored word control respective levels of analog signal attenuation in analog summing networks for converting each of such words into respective R, G, B analog signals for the video monitor. Changing the value of the control bit changes the word read-out from the memory in accordance with the particular color format of the received digital signals.

Video monitor interface circuit for digital color signals

An improved tuning system for a color television receiver embodying a varactor tuner having a controller functioning as a potentiometer to provide a preselected tuning voltage for channel selection. The system includes a tuning voltage supply having a low impedance drive which is serially connected at its output with the controller. The voltage supply applies a preselected source voltage to the controller which is substantially independent of changes in the resistive value of the controller. The tuning voltage supply is combined with automatic fine tuning correction circuitry connected between the automatic fine tuning system and the varactor tuner. The automatic fine tuning correction circuitry applies a correction voltage to the varactor tuner for temperature compensation, fine tuning errors of 500 KHZ or less, etc.

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Knoxville, TN, United States of America

Patrick M Rafter