摘要 |
PURPOSE:To attain the synchronization changeover by adjusting automatically and optimizingly a relative delay time difference in the unit of multi-frames between active and standby signals. CONSTITUTION:Relative delay time adjustment between active and standby signals in the unit of multi-frames is divided into delay time adjustment in a frame and delay time adjustment in the unit of frames by using an active frame pulse 5 and an active multi-frame pulse 6 obtained by establishing multi- frame synchronization and frame synchronization with respect to an active signal string 2, and a standby frame pulse 6 and a standby multi-frame pulse 8 obtained by establishing multi-frame synchronization and frame synchronization with respect to a standby signal string 4, the timewise lead and lag between the active string and the standby string are discriminated, and while the relative delay time difference between the active and standby signals is set to 0, the signal is used for an input to a synchronization changeover 111 to implement uninterruptible switching between the active and standby signals. |