| 摘要 |
PURPOSE:To decrease the noise of not only the flat part but the edge part of a signal with a cheap circuit by providing the second HPF to remove the signal of the band higher than a reproducing video signal removed by the first high pass filter (HPF) and a sub-pass to remove the noise component only of the amplitude smaller than the second HPF output and subtracting the output signal and the reproducing signal. CONSTITUTION:The first noise elimination circuit is composed of a subtracter 3, an HPF 4, a limiter circuit 5 and an LPF 6. An HPF 7 is an HPF to remove only the high area component higher than the high area component to remove it with the HPF 4 from a video signal. The second noise elimination circuit is composed of the HPF 7, a limiter circuit 8 and the subtracter 3. A limiter 8 removes the noise component only of a small amplitude from the output of the HPF 7. By such constitution, the first noise elimination circuit inputs the output of the limiter circuit 5 to the subtracter 3 and removes the noise from the video signal. The second noise elimination circuit is provided in parallel with the first noise elimination circuit and both a flat part noise and an edge noise are decreased. In such a case, the LPF 6 is provided at the rear stage of the circuit 5 and the subtracting quantity of the high area is made smaller at the noise elimination circuit as a whole.
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