| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a synchronization state detecting system for excluding instability of operations of post-stage circuits, by avoiding detecting operations of synchronization/out of synchronism from being repeated, even if the quality of a communication channel has deteriorated, when a synchronization state is detected. <P>SOLUTION: The synchronization state detecting system counts the number of pulses produced, when an error exceeding the error correction capability of the received signal takes place, when a backward protection function section outputs a signal denoting the synchronization state, and outputs synchronous/asynchronous information, on the basis of the number of pulses and gives the information to the post-stage circuits. More specifically, the synchronization state detecting system generates information denoting an asynchronous state when, the number of pulses is a first threshold T1 or longer for a predetermined period, generates information denoting a synchronous state, when the number of pulses is a second threshold T2 (smaller than T1) or smaller, and keeps the information for a just preceding period, when the number of pulses is between the T1 and T2. Thus, in a state with the quality of the communication channel deteriorated wherein the synchronization/asynchronization of a received frame pattern is repeated, a flopping can be suppressed and the instability of operations in the post-stage circuits can be eliminated. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
