| 摘要 |
PROBLEM TO BE SOLVED: To reduce and prevent a defect in the case that out of synchronism takes place between a block number of received data and an output of a frame block counter of the receiver by providing an output of an abnormality processing signal when types of packets differ based on the discrimination by a synchronization detection signal and a count means. SOLUTION: Based on a timing signal generated by a frame block counter 6, a frame synchronization discrimination circuit 5 detects a change point of a BIC given from a BIC detection circuit 2 to discriminate a frame synchronization state. A D/P error-discrimination circuit 8 detects a defect due to misdiscrimination of a data packet and a parity packet caused by deviation in packets resulting from an output of the frame block counter 6 and mis-count of received data. Then a packet deviation discrimination circuit 10 compares the content stored in a D/P error history storage circuit 9 with a predetermined bit deviation discrimination pattern. When the both are unequal, a fault state is discriminated. |
