Wideband analog RGB video processor with negative feedback capability and black level control

摘要

The present invention provides a means and method for wideband analog RGB video processing with capability for negative feedback black level control.PPA wideband analog RGB video processor is provided utilizing gain control circuitry including voltage-to-current conversion circuitry so that received color video voltage component signals are converted to color video current signals for further processing. The gain control circuitry also amplifies the component signals as desired and may provide desirable customer contrast control. Once the component video signals have been processed, they are reconverted by current-to-voltage conversion means and further amplified to provide color video voltage component signals to an output stage for driving color video displays such as CRT's. The wideband analog RGB video processor may further utilize a negative feedback circuit for stabilizing the black level and other characteristics of the video output signal. Desirably, the feedback circuit provides a correction current signal to be combined with the current component signals prior to reconversion into the video output voltage component signals. The color video voltage component signals are tapped to provide optimal feedback information for comparison with a predetermined reference signal to generate correction signals. Feedback is obtained in a coordinated fashion with the video signal so that black level information may be obtained. Capacitive storage means insure accurate correction throughout successive horizontal line intervals. Additional band width limiting capacitance is minimized by tapping the video output signal at a relatively low impedance level in the video processing stage.