| 摘要 |
PROBLEM TO BE SOLVED: To obtain a Y/C separation circuit removing cross color interference when a luminance signal is non-correlative in vertical direction and removing dot interference when only a signal 1H exists or is absent. SOLUTION: Delay circuits 11, 12 respectively delays an inputted composite video signal by a horizontal scanning period in which the phase of the chrominance subcarrier is inverted and band-pass filters(BPFs) 13 to 15 respectively obtain signals 0H, 1H, 2H from the composite video signal by using the frequency band of the chrominance subcarrier as a pass band. An intermediate value detection circuit 29 detects the non-correlation of a luminance signal from signals obtained by inverting the signals 0H, 2H and the signal 1H as it is. Second and third intermediate value detection circuit 30, 31 input the signal 1H, the signal 0H or 2H and a silent signal and respectively detect correlation between the signals 1H and 0H and between the signals 1H and 2H. Each of subtractors 33, 34 subtracts an intermediate detection value from the signal 1H to remove the noise component. An intermediate value detection circuit 32 detects an intermediate value among an output from the circuit 29 and outputs from both subtractors 33, 34 as a chrominance signal.
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