| 摘要 |
PURPOSE:To obtain a vertical reference signal digitally and stably with a small er circuit scale by constituting the titled circuit that a vertical synchronizing signal is synchronized with a horizontal synchronizing signal by a synchronizing circuit and a stable synchronizing signal is obtained through the phase discrimi nation with a reproduced vertical synchronizing signal. CONSTITUTION:A horizontal synchronizing circuit 11 obtains a horizontal syn chronizing signal VH synchronously with a horizontal synchronizing signal from a vertical synchronizing signal V1, a phase discriminating circuit 12 compares it with the phase of a reproduced vertical synchronizing signal V2 to detect coincidence or dissidence. In response to the coincidence or dissidence of the detected output, a coincidence counter 13 or a dissidence counter 14 is incre mented complementarily, and when the count of them reaches a prescribed value, they output a carry respectively. A flip-flop 15 is set by the carry of the counter 13 and reset by the carry of the counter 14. An output of the flip- flop 15 allows a data selector 16 to select and output any of the horizontal synchronizing signal VH and the reproduced vertical synchronizing signal V2 as a synchronizing signal V.
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