| 摘要 |
PURPOSE:To make it possible to detect the range to the point of breakdown by an on line real time method, by sending optical signals having different wavelength from one terminal station into one optical fiber with the wavelength being multiplexed, and measuring the time difference of signal discontinuance at the other terminal station. CONSTITUTION:The main signal or the breakdown point searching signal from the terminal 3 in the terminal station 1 is supplied to a long wavelength optical transmitter 4 and to a short wavelength optical transmitter 5 as a modulating wave, respectively. Each modulated optical output is inputted to the optical cable 14 through a wave combiner 6. In the terminal station 2, the arriving light from the cable 14 is divided into the long wavelength signal and the short wavelength signal by a wave divider 7 and both signals are given to receivers 8 and 9. The time of discontinuance of the light is measured by measuring parts 10 and 13 based on the discontinuance information of the optical signal of each receiver. Based on the time difference, the range to the breakdown point in the cable is computed by a computing part 11 and displayed on a display part 12. |
