| 摘要 |
<p>PURPOSE:To always obtain a stable clock at the time when a video signal cannot be obtained and the video signal is restored. CONSTITUTION:The phase of the synchronizing signal in an input video signal and that of a feedback clock are compared with each other by a phase comparing means (second phase comparing circuit) 5 of a phase synchronizing circuit 3, and the output of this phase comparing means 5 is held at a certain value by a holding means (sampling and holding circuit) 12 at the time of drop-out, and the feedback clock is synchronized with the synchronizing signal by control means (an input signal detecting circuit 13 and a counter control circuit 14) at the time of restoration from drop-out.</p> |
