| 摘要 |
<p>PURPOSE:To discriminate a faulty section without adding any complex function by sending an FM tone, assigned to a repeater and terminal station, to a prearrangement line constituting a phantom circuit, by detecting it by the repeater and terminal station to make a return connection of up and down circuits, and by detecting a return signal by a carrier-frequency terminal station. CONSTITUTION:An FM tone assigned to one repeater, transmitted from the carrier- frequency terminal station via a prearrangement line by constituting a phantom circuit, is detected by detector 10 and up and down circuit reproduction repeating outputs are switched by switch 11 with detection signal 12 to send out return and up (down) circuit repeating outputs as a down (up) circuit output. For this purpose, the carrier-frequency terminal station judges whether the return signal is normal or not to detect a fault of a repeating section.</p> |
