| 摘要 |
<p>PURPOSE:To prevent the delay of synchronous hunting by providing a retiming circuit for outputting a holding mask signal, and a logic circuit for inhibiting the output of a hunting holding signal. CONSTITUTION:This circuit is provided with a synchronizing pattern detecting circuit 11, a timing pulse generating circuit 12, a frame pulse generating circuit 13, a synchronization counting circuit 14, and a synchronization protecting circuit 15. Also, the circuit is provided with a retiming circuit 16 for outputting a holding mask signal 1i when a synchronization counting signal 1h outputted from the synchronization counting circuit 14 is counted and reaches a counting value N-1, and a logic circuit for inhibiting an output of a hunting holding signal 1j by the holding mask signal 1i outputted from the retiming circuit 16. In such a way, since the hunting holding signal 1j is temporarily inhibited, a hunting delay time is not added to a synchronization reset time. Accordingly, the delay of synchronous hunting is prevented and the synchronization reset time can be shortened.</p> |
