Patent ID: 8189112

Claim:
A separating circuit which separates a composite video signal containing combined luminance and chrominance signals, the separating circuit comprising: a comb filter to separate the chrominance signal and concurrently output a reference composite video signal serving as a reference, a lead composite video signal that is at least one video scan line ahead of the reference composite video signal, and a delayed composite video signal that is at least one video scan line behind the reference composite video signal; a filter to extract a high-frequency chrominance component from the chrominance signal; a first calculation circuit to add the high-frequency chrominance component to the chrominance signal to produce a sum result and to subtract the sum result from a reference composite video signal to output a first luminance signal; a second calculation circuit to subtract the chrominance signal from each of (i) the reference composite video signal, (ii) the lead composite video signal, and (iii) the delayed composite video signal to generate a plurality of concurrent luminance signals that undergo vertical filtering to generate a second luminance signal; and a selection circuit to selectively output either the second luminance signal when the high-frequency chrominance component has a value larger than a reference value or the first luminance signal when the high-frequency chrominance component has a value smaller than the reference value.