| 摘要 |
<p>PURPOSE:To perform a rapid and proper fault processing, by providing a control circuit in each repeating installation to monitor the output of the repeating installation for a fault search current and by changing the oscillation frequency of an oscillator for the fault search current to the second frequency and transmitting it if abnormality is detected. CONSTITUTION:When repeating installations 1-3 are normal, natural frequencies f1, f2, and f3 are inputted to them from oscillators 5-7 for fault search currents repectively, and repeating installations output respective natural frequencies in prescribed levels. If some repeating installation, for example, the repeating installation 2 becomes abnormal, the output level of the natural frequency f2 exceeds a constant range. Therefore, a control circuit 9 detects the abnormality to change the oscillation frequency of the oscillator 6 for the fault search current to the second frequency f0. As the result, receiving currents of natural frequencies f1 and f3 and the second frequency f0 are inputted to a terminal station equipment 4. When detecting the second frequency f0, the terminal station equipment 4 recognizes that some repeating installation is faulty and issues an alarm or the like.</p> |
