Luminance and chrominance signal separator using correlation detection

Abstract

A device that separates a luminance signal and a chrominance signal from an input composite color television signal, suppressing cross color interference and keeping a good color transient characteristic, by selecting characteristics of the color bandpass filters according to a vertical correlation value after obtaining a chrominance signal at an adaptive type comb filters. The apparatus includes a cascade connection of a plurality of delay devices each one of which delays one horizontal period; chrominance correlation detecting circuits for obtaining correlation of a chrominance signal between a reference signal and a signal at the vertical vicinity of the point of the reference signal on the screen, where an output signal of the central delay device is regarded as a reference signal; luminance correlation detecting circuits for obtaining correlation of a luminance signal between the reference signal and a signal at the vertical vicinity of the point of the reference signal on the screen; a correlation judging circuit for judging if there is correlation from the correlation of the chrominance signals and the correlation of the luminance signals; comb filters for separating a chrominance signal from the composite color television signal; and a selector for selecting an output of the comb filters according to the judgment of the correlation.