Patent ID: 7250985
Filing Date: 2007-07-31
Classification: H04N

Abstract:
1. A color demodulation circuit that demodulates color-difference signals from a chrominance carrier signal, including: a first amplifier circuit for amplifying an amplitude of the chrominance carrier signal; an ACC circuit for variably controlling a degree of amplification of the first amplifier circuit in accordance with the inputted chrominance carrier signal; a chroma killer generation circuit for detecting an amplitude level of a burst portion in the chrominance carrier signal from an output of the ACC circuit as well as detecting a phase shift of the burst portion in the chrominance carrier signal from an output of the first amplifier circuit, and generating a chroma killer signal on the basis of detection results; a second amplifier circuit for amplifying an amplitude of the chrominance carrier signal; a selector for selecting one of an output from the first amplifier circuit and an output from the second amplifier circuit; a control circuit for setting a degree of amplification of the second amplifier circuit and switching the selector on the basis of the chroma killer signal; and a color-difference output demodulation circuit for demodulating color-difference signals from the output of the selector.