| 摘要 |
PURPOSE:To strengthen a vertical synchronization in a portable TV etc. and to obtain a stable picture by opening a gate by the numbers of count of a horizontal synchronizing signal closing the gate after a vertical synchronizing pulse is passed. CONSTITUTION:The oscillating output of VC01 that is synchronizing with a horizontal synchronizing pulse and is oscillating with a frequency of 2fH is reduced to 1/525th by a counter 2 and resets the counter 2 through an OR circuit 4 and one signal is outputted at every one field. This outputted signal opens a gate circuit 3 and the counter 2 is reset after a vertical synchronizing pulse V-SYNC is passed. Therefore, the outputted signal of the counter 2 is outputted with the same phase of the vertical synchronizing pulse. Also, the circuit 3 is controlled to close by the vertical synchronizing pulse V-SYNC is passed. Therefore, the outputted signal of the counter 2 is outputted with the same phase of the vertical synchronizing pulse. Also, the circuit 3 is controlled to close by the vertical synchronizing pulse that is passed through the circuit 3.
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