MONITORING SYSTEM FOR LIGHT REPEATER

摘要

PURPOSE:To improve a section estimation accuracy at the time of generating a trouble and to collect maintenance information during the operation with a simple circuit constitution by returning to a landing station and monitoring the fluctuation quantity of an electric signal after the output of a light repeater is converted to an electric signal. CONSTITUTION:A part of a light signal L0 for a main line of the emission of an ascending light repeater 3 is branched to a light signal L1 for monitoring by a branching circuit 11, converted to an electric signal E1 for monitoring by a photodiode 12 and the change is measured. After an electric signal E1 for monitoring of the output of the photodiode 12 is converted to a binary signal E2 for monitoring through a monitoring signal line 18 by an A/D converting circuit 13, a binary phase modulation is executed to a light signal L' for the main line of descending optical fibers 2 and 2' lines for main lines and by a phase modulator 14 of a descending light repeater 4 and the transmission is executed to a landing station with the in-service. The designation of the ascending repeater 3 (reproduction repeating circuit) to execute the monitoring is executed by an in-service control signal to transmit from the landing station through a light signal L for a main line.