| 摘要 |
<p>PURPOSE:To detect a frame synchronization bit at a higher speed by detecting a synchronization bit during forward protection and setting the backward protection state immediately after synchronizing step-out. CONSTITUTION:When a location in an input data string is dislocated, the outputs of coincidence/non-coincidence detecting circuits 13a-13n whose coincidence is detected when the synchronization is confirmed are discordant, a protective circuit 14 is set in the forward protection state and discordance exceeding the protective stage number is detected, the synchronizing stepping-out is set. In this case, in the forward protective state, a synchronization bit detection circuit detecting the synchronization bit so far among the synchronization bit detection circuits 12a-12n detects a synchronization bit, then a protective circuit 14 sends a reset pulse S6 to a pulse generating circuit 15. The circuit 15 changes the phase of a frame synchronization pulse S7 of an output of the circuit 15 to retrieve the presence of detection of the synchronization bit of the circuits 12a-12n and detects any of the circuits 12a-12n detecting the synchronization bit immediately.</p> |
