| 摘要 |
PURPOSE:To prevent out of synchronism at each multi-frame by unlocking the synchronization at each frame and then locking the synchronization when the state not synchronized at each multi-frame is consecutive for a prescribed time after the synchronization is established at each frame. CONSTITUTION:A frame synchronizing circuit 11 takes synchronism with a reception digital signal PCMR at each frame based on a reception signal CLKR, outputs a frame signal SFR, which is fed to a multi-frame synchronizing circuit 12. The circuit 12 is activated so as to take synchronism with the signal PCMR at each multi-frame. A timing circuit 13 is activated with a signal S1 when the circuit 11 is synchronized and with a signal S2 when the circuit 12 is not synchronized, the time after the synchronization is taken at each frame until the synchronization at each multi-frame is taken is counted, and when this time exceeds a predetermined set time T, a control signal SC is outputted. The circuit 11 receives the signal SC to release the synchronizing state forcibly and the synchronization at each multi-frame is taken by taking synchronism again at each frame. |
