| 摘要 |
PURPOSE:To shorten a time to establish a synchronization by repeatedly sending out only a synchronizing signal when it is decided as the condition of off- synchronization. CONSTITUTION:When the off synchronization is generated at a receiving station 2, a switch circuit 23 is switch-set to a second synchronizing signal detection part 22 side and an alarm signal to station AS is sent out from an alarm sending-out part 24 to station 24. A transmitting station 1 knows the off synchronization at an alarm reception part 14 to station 14, switches a switch circuit 13 from a multiplexing part 12 side to a synchronizing signal generation part 11 side, only a synchronizing signal is repeated and sent out. Thus, the receiving station 2 can detect the synchronizing signal within an extremely short time at the time of the off-synchronization and consequently a synchronization retraction can be speedily executed. |
