| 摘要 |
PROBLEM TO BE SOLVED: To eliminate the problem of the screen of a television set becoming disturbed by a vertical synchronization signal abruptly generated even though a synchronization signal for horizontal synchronization is contained in a video signal. SOLUTION: A synchronization signal output device is provided with a signal processing circuit 50 (synchronization signal output means), which detects the pulse width of the synchronizing signal contained in the inputted video signal and produces a horizontal synchronizing signal and a vertical synchronizing signal according to the detected pulse width, a co-polarity superimposing signal generating means for generating a superimposing signal of the same polarity with that of the synchronizing signal contained in the video signal from this horizontal synchronization signal and a signal superimposing circuit 70 (signal superimposing means) for superimposing this superimposing signal to the video signal. Since the superimposing signal which is produced from the horizontal synchronization signal and has the same polarity as that of the synchronization signal, the video signal is amplified by the component of the synchronization signal for horizontal synchronization. Thus, it is not required to additionally provide an oscillation circuit and a frequency-dividing circuit.
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