| 摘要 |
PROBLEM TO BE SOLVED: To provide a clamping device which can clamp MUSE signals by accurately reproducing a reference level without receiving any influence from a video signal section. SOLUTION: MUSE signals are inputted to a clamping circuit 20A and a switch 12 through a roll-off filter 2. When the DC level of the MUSE signals from the filter 2 is reproduced based on reference clamping level information contained in the MUSE signals by removing the low-pass component of the MUSE signals by means of the clamping circuit 20A, the influence of a video signal section is removed in such a way that the switch 12 is conducted for a prescribed period of time in the video signal section of a scanning line before the HD of the MUSE signals and the average value of the signals passed through the switch 12 is obtained by means of an average value circuit 13. Then the signals are matched to the clamping period of the clamping circuit 20A (turning-on period of a switch 8) by delaying the signals by means of a delay circuit 14 and subtracting the delayed output of the circuit 14 from the DC level for clamping of the clamping circuit 20A by supplying the delayed output to a subtraction circuit 15.
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