| 摘要 |
PURPOSE:To execute the monitor of a repeater in a state being near a usual operating state by executing a modulation for repeating a non-inversion and an inversion by a frequency corresponding to a physical quantity to be monitored which is set to a repeater, with respect to a false random signal of the same mark rate as that of an usual operation or an average mark rate being near said mark rate, which is sent to the repeater concerned from a terminal station. CONSTITUTION:First of all, a loop-back instruction is superposed on a main signal and sent to a repeater to be monitored, from a terminal station 20, and a loop-back is applied to its repeater. Subsequently, a false random signal from an optical transmitter 21 of the terminal station 20 is sent on by the repeater 5 concerned, and received by an optical receiver 22 in the terminal station 20. The optical receiver 22 extracts a clock from a receiving signal and inputs it to a false random signal generator 26, and it is synchronized with a false random signal generator 23. A false random signal a(2-1) which is sent from the terminal station 20 is supplied to an exclusive OR circuit together with a signal b(2-2) of a frequency corresponding to a voltage to be monitored in the repeater, and a modulation for repeating a non-inversion and an inversion is executed, and a modulated signal (2-3) is sent back to the terminal station 20. |
