| 摘要 |
PURPOSE:To surely select an optical repeater and an optical fiber for a line fault retrieval or the like by detecting it that an input optical signal to the optical repeater is interrupted and revising a monitored value to a prescribed fixed value. CONSTITUTION:An input optical signal to an optical repeater is converted into an electric signal at an optic/electric conversion circuit 1 and signal reproduction processing is implemented in the state of an electric signal at an equalizer amplifier 2 and an identification circuit 4 and the result is restored to an optical signal and outputted by an electric/optic conversion circuit 5. The level of the input optical signal is monitored by the monitored value of the electric signal. Then the interrupting state of the input optical signal to the optical repeater is monitored by an input interruption detection section 7, a changeover switch 8 is switched from a monitor circuit 2-1 to a fixed monitor value setting section 8-1, in which the monitored value is revised into a fixed monitor value. Thus, whether a fault is resident in an optical fiber or in the optical repeater is surely discriminated on the occurrence of the line fault thereby selecting the optical repeater and the optical fiber surely. |
