| 摘要 |
PURPOSE:To output an exact continuous horizontal pulse train, by generating a continuous horizontal pulse sequence irrespective of a signal waveform of a vertical synchronizing signal period. CONSTITUTION:A synchronizing signal is separated from a composite video input signal by a synchronizing separator circuit 3. The separated composite synchronizing signal is integrated by a vertical synchronizing signal detecting circuit 4. An RS flip-flop 7 is set by a control signal from the vertical synchronizing signal detecting circuit 4. A timing circuit 5 outputs a pulse of constant width after a prescribed time of a trigger input. Also, a timing circuit 6 outputs a pulse of constant width after a horizontal signal period. An output of the timing circuit 6 is counted by a counter 11, and when a prescribed number of pulses has been counted, a carry signal is outputted from the counter 11. A continuous pulse train of a horizontal period is obtained by taking OR of outputs of the timing circuit 5 and the timing circuit 6 by an OR circuit 10. |
