| 摘要 |
PURPOSE:To improve the level change in the carrier chrominance signal by constituting a feedback loop to a Y-shaped comb-line filter so as to obtain a control signal from the feedback loop. CONSTITUTION:A luminance signal Y from a demodulation circuit 1 in a Y- shaped comb-line filter 10 is fed to a delay circuit 12 and a subtraction circuit 13 through the subtraction circuit 16, a noncorrelation component DELTAY from the circuit 13 is fed back to a subtraction circuit 16 through an attenuator 17 to form the feedback loop 10A, the component DELTAY is fed to a limiter 14 through an attenuator 18. A control signal S2 is formed from the component DELTAY and fed to the C-type comb-line filter 20. Thus, since the level of the carrier chrominance signal C is corrected while keeping a delay time of the delay circuit 12 as one horizontal period, the vertical resolution of the luminance signal Y is not reduced.
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