| 摘要 |
PURPOSE:To sensure the fault supervision by detecting a fault alarm of an optical PCM repeater with an FM signal superimposed on a main signal. CONSTITUTION:If the optical PCM releater 2 is faulty and any of photoelectric converters 21, 28 and electrooptic converters 23, 26 generates an alarm signal, a signal generator 24 generates a pulse signal specific to each optical PCM repeater 2. The generated pulse signal is modulated into an FM signal by an FM modulator 25 and superimposed on the main signal via the electrooptic converters 23, 26. The pulse signal superimposed on the main signal is demodulated by an FM modulator 13 or 33 respectively at one terminal station 1 or other terminal station 3 in this way and detected by a detector 14 or 34 to discriminate a faulty optical PCM repeater with the specific pulse signal at each optical PCM repeater 2 at the same time. |
