Patent ID: 6046779
Filing Date: 2000-04-04
Classification: H04N

Abstract:
A circuit arrangement for processing a color signal modulated on a carrier wave having a first carrier frequency, the circuit arrangement comprising:first mixing means having a first input for receiving the color signal modulated on the carrier wave having the first carrier frequency, and a second input for receiving a first mixing signal, said first mixing means converting the first carrier frequency of the carrier wave to a second carrier frequency, and providing the color signal modulated on the carrier wave with the second carrier frequency as an output signal;a comb filter circuit coupled to receive the output signal of the first mixing means, said comb filter circuit providing a comb-filtered output signal;second mixing means having a first input for receiving the comb-filtered output signal, and a second input for receiving a second mixing signal, said second mixing means converting the second carrier frequency of the carrier wave of the comb-filtered output signal to a third carrier frequency;first phase shifting means for subjecting the first mixing signal to a phase shift of a given magnitude after a given number of picture lines of the color signal, the phase shift being, each time, effected in addition to any previously applied phase shifts, and being selected to compensate for a non-integral ratio between a period of one picture line and a period of the color signal modulated on the carrier wave at the first carrier frequency, in such a manner that a period of the carrier wave on the input of the comb filter circuit begins at a beginning of a next picture line; andsecond phase shifting means for subjecting the second mixing signal to a phase shift of the same magnitude but of opposite sign and at the same instant as the phase shift performed by the first phase shifting means.