| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem that clamping cannot be properly performed, when the clamping is performed by using a clamp pulse based on a pseudo horizontal synchronization signal having a short pulse width existing in a copy guard signal period. SOLUTION: This circuit is provided with a clamp circuit 3 for clamping a composite video signal including a copy guard signal having an amplitude between white and black and having a pseudo horizontal synchronization signal, a luminance signal, and a synchronization signal; a synchronizing separator circuit 5 for separating the synchronization signal from the composite video signal clamped by the clamp circuit; and a synchronization signal determining circuit 6 for determining whether or not the synchronization signal from the synchronizing separator circuit arrives at a period of the horizontal synchronization signal, and cutting off a signal having a period shorter than the period of the horizontal synchronization signal to enable only a signal having the horizontal synchronization period to pass. COPYRIGHT: (C)2004,JPO&NCIPI
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