| 摘要 |
The invention provides a monitor for monitoring the condition of fibre optic communication cables. The system employs one or more of the optical fibres of a cable to monitor the cable structure for damage or kinks. By using two separat e laser sources and simultaneously monitoring the optical losses at two distinct a nd separate wavelengths, the loss signature of the monitored fibre is determined, analyzed and related to the mechanical condition of the cable structure. To moni tor splice points for moisture, a special optical splice sensor unit detects any pen etration of water into the splice and transmits a coded alarm signal over the monitored f ibre to the optical receiver. Every splice location is assigned a unique sensor code. Th e optical splice sensor is driven by moisture detection cell, which forms a single cell water activated battery. Water entering the monitored splice closure wets the ta pe, which activates the cell. The cell generates sufficient voltage and current to p ower timing, code generation and modulator circuits in the sensor unit for an extende d period of time. The activated circuit drives a modulator which modulates the lig ht travelling down the fibre. The modulated light is monitored at the equipment off ice and the address of the alarming sensor decoded.
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