| 摘要 |
PURPOSE:To reduce noise and to suppress the deterioration of a vertical resolution by providing a limiter within the loop of a feedback-type comb line filter. CONSTITUTION:A reproducing luminance signal (a) that is inputted to a terminal 1 is supplied to the feedback-type comb line filter that consists of subtracters 2 and 4, a 1HDLY 3, a limiter 5 and a coefficient circuit 6 and is changed to a signal (b) at the subtracter 2 and is changed to a signal (c) at the subtracter 4. The signal (c) is changed to a signal (d) in the high area component of a space frequency in the vertical direction that is included in an inputted signal with amplitude limiting of limiter level Li at the limiter 5 and is changed to a signal (e) with multiplying by a coefficient k1 at a coefficient circuit 6 and is supplied to the subtracter 2. By providing the limiter 5, the coefficient k1 of the coefficient circuit 6 is made smaller against the amplification of the high area signal size in the vertical direction and thereby, the cut-off frequency of the feedback type comb line filter is higher against the amplification of the high area signal size and a response is fastened. Thereby, the effect of noise reduction is obtained extending from low area frequency to high area one.
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