An input composite color video signal is processed to derive a luminance signal and three primary color signals first, and then only a high frequency component of the luminance signal is A/D converted by a first A/D converter, while only low frequency component of each of the three primary color signals...http://www.google.com.au/patents/US4549201?utm_source=gb-gplus-sharePatent US4549201 - Circuit arrangement for digitizing and storing color video signal
