Patent ID: 6538702
Filing Date: 2003-03-25
Classification: H04N

Abstract:
A digital color signal reproducing circuit comprising:an A/D converter that samples an analog composite signal using a sampling clock and converts said analog composite signal into a digital composite signal; a YC separator that separates a luminance signal and a chrominance subcarrier signal from said digital composite signal; a gain controller that controls the amplitude of said chrominance subcarrier signal and supplies output signal; a first multiplier that multiplies said output signal of said gain controller by sine component of a reference subcarrier signal and outputs a color-difference signal (R-Y signal) together with high frequency components thereof; a second multiplier that multiplies said output signal of said gain controller by cosine component of said reference subcarrier signal and outputs a color-difference signal (B-Y signal) together with high frequency components thereof; a burst-period cumulative adder that extracts signal within burst gate pulse period from the output signal of said first multiplier, cumulates the extracted signal, and supplies output signal; a clock generator that controls a clock frequency in accordance with output of said burst-period cumulative adder and outputs a clock pulse locking to a burst signal; and a reference subcarrier generator that receives said clock pulse and a control signal as input and that controls frequency of output signal thereof in accordance with said control signal and outputs said sine and cosine components of said reference subcarrier signal; wherein frequency of said reference subcarrier signal is controlled in accordance with broadcasting systems by said control signal, wherein said clock is used as said sampling clock.