| 摘要 |
PURPOSE:To use a frame pattern and a staff control bit in common by defining plural frame patterns and transmitting simultaneously frame synchronizing information and staff control information. CONSTITUTION:A received transmission line signal is inputted to the 1st frame pattern detectioncircuit 2, the 2nd frame pattern detection circuit 3 and a staff control discrimination circuit 4 via an input terminal 1. Thus, the detection circuit 2 detects the 1st frame pattern ABCDE, the detection circuit 3 detects the 2nd frame pattern abcde and the discrimination circuit 4 applies discrimination of staff pulse presence/absence to the bit of frame pattern by majority decision system. Based on the normality/abnormity of the rate of staff pulse presence/absence, a synchronism detection signal 6 is outputted. A frame synchronizing circuit 9 applies the control of synchronization restoration and synchronization protection based on an output of synchronization detection signal 6 and a frame pattern detection signal 8. Then a control output circuit 10 outputs various control signals from output terminals 11a-11n. |
