Colour video signal processing circuit - has four quadrant multipliers coupled to difference amplifier with current reflection circuits

摘要

The circuit uses a 4 quadrant multiplier (19) supplied with the colour video signal and a control signal for amplification adjustment. A second 4 quadrant multiplier (20) receives a chrominance signal extracted from the video signal and a second control signal. The outputs of both multipliers (19,20) are fed to a difference amplifier (3) with current reflection circuits (7...11,12...16) in the collector leads coupled to the outputs of the multipliers (19,20). A second difference amplifier (17) receives the outputs of the current reflection circuits (7...11,12...16) and provides the processed colour video signal at its output. ADVANTAGE - Allows phase linear adjustment of chrominance amplitude.