| 摘要 |
PROBLEM TO BE SOLVED: To allow stages after a faulty point to be restored to an original frame phase by supplying an accurate network frame signal to the stages, even at occurrence of a momentary interruption continued for a long time or after resetting of a channel interface circuit. SOLUTION: A counter 52 generates an internal frame signal S6 following after a network frame signal S2 in synchronized operation. Furthermore, in the synchronized operation, a reset signal generating circuit 55 and counters 56, 57, 58, 59 function to measure a phase difference between the internal frame signal S6 and a self-running frame signal S13 at a prescribed period. A memory 60 and a mean value calculation section 61 generate phase difference information as a mean value of four measurements of the phase difference. At occurrence of a state out of synchronization, the counter 52 generates a self-running internal frame signal S6 based on a self-running clock S3 and corrects the period of the internal frame signal S6, in response to the phase difference information at each prescribed period. |
