| 摘要 |
PURPOSE:To prevent a wrong parity error pulse which is generated in a switching mode by inserting the parity operational result into the frame synchronizing bit position set after the frame synchronization is decided for transfer the operational result and extracting this result after the non interruptible synchronizing switching. CONSTITUTION:The parities of signals are checked for a working circuit and a stand-by circuit by a working circuit-only error detecting part 63 and a stand-by circuit-only error detecting circuit 64 respectively. If a parity error is detected, each error detecting part outputs an error pulse. The comparison result inserting circuits 61 and 62 receives the error pulses and insert the error information into the frame synchronizing bit position of the signal of the working or stand-by circuit whose frame synchronization is decided. The signals of both circuits are switched by a non interruptible synchronizing switch circuit 2 and transmitted. Then the signal quality is monitored with extraction of the error information out of the frame synchronizing bit position of the switched signal. |
