| 摘要 |
<p>PURPOSE:To shorten a frame resynchronization time at the time of the phase shift of received data by providing two frame synchronism protecting circuits which differ in the number of times of step-out detection, and selecting and outputting frame pulses of one circuit which synchronizes earlier when a step-out state is entered. CONSTITUTION:The two frame synchronism protecting circuits I and II which differ in the number of times of step-out detection are provided behind a frame detecting circuit 3 and if a frame step-out occurs, frame pulses of one frame synchronism protecting circuit which synchronizes earlier are selected by a selector 6. Consequently, the frame pulses generated by the circuit which finishes resynchronization earlier at the time of the step-out are outputted as frame pulses for synchronous operation, then the frame resynchronization time from the occurrence of the step-out to the completion of resynchronization can be shortened.</p> |
