| 摘要 |
PURPOSE:To obtain a stable horizontal oscillation signal even to various kinds of video signals by sample and holding a just preceding DC signal and giving the result to a horizontal oscillation circuit during the period of a frequency different from the horizontal frequency in a composite synchronizing signal. CONSTITUTION:A DC signal DC from an integration circuit 2 is given to a sample-and-hold circuit 4. The sample-and-hold circuit 4 samples and holds the DC signal DC incoming only when a vertical synchronizing signal VD is given and passes through as it is the DC signal DC during the other period. That is, the sample and holding circuit 4 samples and holds the just preceding output signal during the vertical synchronizing period and gives a signal in response to an input DC signal DC to the horizontal oscillation circuit 3 of the next stage. Thus, the horizontal oscillation circuit 3 is oscillated in response to the output signal and a stable oscillation output is obtained even when a video signal of a different format is given.
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