| 摘要 |
PURPOSE:To prevent a horizontal synchronizing signal from being omitted even when there is an extreme level change in an input video signal by comparing the video signal with a peak detecting signal of the video signal obtained by a time constant circuit to separate the horizontal synchronous signal. CONSTITUTION:An input video signal is reversed and amplified by a reversing amplifier 1 and this output is branched into two, one is inputted to a negative input terminal of a comparator 2 and the other is inputted to a peak detector composing of a Schottky diode D1, capacitor C1 and a resistance R4 to detect the peak, inputted to a positive input terminal of the comparator 2 and separates the horizontal synchronous signal by comparing therewith. A reference voltage follows an end level of the horizontal synchronous signal of the video signal, compares therewith, thereby separates the horizontal synchronizing signal. Therefore, even if there is a rapid level change in the input video signal or there is a sag wave shape, the horizontal synchronizing signal is not omitted nor the synchronization is shifted in the television and the cause of the level change in a clamper is eliminated.
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