Video processing system including comb filters

摘要

In a video processing system including comb filters for separating interleaved luminance and chrominance components, the time of occurrence of the color synchronizing component of the composite color video signal is detected after the comb filtering and separating of the luminance and chrominance components. The composite signal components include spurious frequency variations which accompany the composite signal during playback from a video disc. A first phase locked loop coupled to a frequency translator is used to remove the spurious frequency variations from the separated and frequency translated chrominance components. A second phase locked loop is connected between a second frequency translator and a clock controlled delay line. The second phase locked loop tracks the spurious frequency variations in a manner to assure that accurate combing of the component signals occurs at the output of the comb filters. The same reference frequency is used in the first phase locked loop as well as in the second frequency translator.