| 摘要 |
PURPOSE:To execute a bracketing work of a fault without halting a service by receiving simultaneously a folded signal from a transmitting part of the own station by the same photodetector as a transmitting signal, in a receiving part, and thereafter, separating both of them by a frequency separating circuit, so that an optical output signal of the transmitting part of the own station can be monitored even when an optical signal from the other station is being received. CONSTITUTION:A folded signal from a transmitting part of the own station and a transmitting signal which has transmitted through an optical fiber are inputted simultaneously to the same photodetectors 7, 17 in a form of an optical signal, in a receiving part. An electric signal which has been photoelectric-converted by the photodetector 7 and 17 becomes a multiple signal, and separated into the multiple signal by a frequency separating circuit 10 and 20. These separated signals are multiple-separated and demodulated by multiple separating and demodulating circuits 25, 26 and 27, 28, respectively, and a demodulating signal is obtained in terminals S01, M02 and S02, M01. As a result, an operation of transmitting parts 2, 3 and 12, 13 of a transmitting device can be monitored at all times by the monitor terminal M01 and M02. |
