| 摘要 |
PURPOSE:To collate normally the active/standby signals in any case by allowing a standby system to attain establishment of synchronization before the active/ standby signals are collated in the N:1 active/standby switching system. CONSTITUTION:Input signals A1-An identical to those to N-set of active systems ACT1-ACTn are selected at each collation time T and inputted as a signal Ai to a frame synchronous circuit of a standby system ST, the frame synchronous circuit is in the state of out of synchronism at each collation time T by using a signal K1 and the synchronization establishment is performed immediately from the locking operation. That is, the frame synchronization is established by using a frame synchronization establishment discrimination signal K2 at a time t0 within a time t1 not collating the active/standby signals. Thus, it is possible to compare and collate normal active/standby signals at a time t2 collating the active/standby signals by a collation circuit C2 and the collation is discriminated by a discrimination circuit J. |
