Patent ID: 7092038

Claim:
An adaptive Y/C separation circuit comprising: a vertical correlation detection means for converting chrominance signals existing in color video signals of three scanning lines to a UV plane coordinate, analyzing the correlation coefficients of the chrominance signals of two adjacent scanning lines, and then outputting an indicative signal representing the correlation coefficients; a signal mixing means for extracting two chrominance signals from the color video signals of the three scanning lines, and determining a mixing ratio for the two chrominance signals in accordance with the indicative signal so as to output an adjusted chrominance signal; a horizontal correcting means for removing residual luminance signal component from the adjusted chrominance signal output by the signal mixing means, so as to generate a restored chrominance signal approximately matching an actual chrominance level; and a subtraction means for subtracting the restored chrominance signal from one color video signal of one of the three scanning lines, to produce a luminance signal approximately matching an actual luminance level; wherein the UV plane coordinate conversion is to demodulate sine waves and cosine waves in the color video signal using a chroma demodulator, to convert the sine waves and cosine waves to multiple points on the UV plane coordinate for variance analysis, and to calculate least values and difference values based on the multiple points to produce the indicative signal.