Color signal processing apparatus using a plurality of sample-and-hold circuits and a single switched A/D converter

Claim 1

A color signal processing apparatus, comprising: input means for inputting, in parallel, a plurality of color component signals of an input color video signal; generation means for generating a sampling pulse every horizontal scanning period so as to perform sampling of a color video signal every horizontal scanning period, wherein the sampling pulse is in synchronism with a horizontal synchronizing signal, and the sampling is performed for one line in a direction perpendicular to a horizontal scanning direction within a color video signal generation period for one image plane; wherein said generation means includes: means for receiving the horizontal synchronizing signal and producing the sampling pulse, and means for receiving a clock and the sampling pulse and outputting an analog-to-digital conversion indicating signal; a plurality of sample-and-hold circuits for sampling and holding, at the same sampling time, each color component signal of the color video signal in response to the sampling pulse, each of said plurality of sample-and-hold circuits being respectively associated with each one of the plurality of color component signals; a selection circuit for sequentially selecting outputs of said plurality of sample-and-hold circuits at a selection timing within a period up to the generation of the next sampling pulse; and a single analog-to-digital converter for sequentially analog-to-digital converting the outputs of said selection circuit in synchronism with the selection made by said selection circuit, responsive to the analog-to-digital conversion indicating signal.