| 摘要 |
PURPOSE:To perform frame synchronization on a time-division multiplex transmission line effectively by shortening the time up to the establishment of synchronism up to the maximum number of rear protection stages of individual synchronism protecting circuits. CONSTITUTION:The 1st synchronism protecting circuit I synchronizes with a received signal and a frame bit is inserted newly by a frame bit inserting circuit 9 regardless of the synchronism state of the circuit I, thereby synchronizing frames of a signal which is reconstituted by the circuit 9. The 2nd synchronism protecting circuit II initialize the synchronism protection state of the circuit I with a frame bit dissidence signal outputted by the circuit I before the synchronism establishment of the circuit I. In this case, the time up to the synchronism establishment is shortened to the rear protection time of the circuit I. |
