| 摘要 |
PURPOSE:To monitor the operating state of an incoming amplifier and an outgoing amplifier at the uppermost point of a transmission line by allowing the incoming and outgoing amplifier to send a repeater monitor signal subjected to amplitude modulation by a modulation signal of a signal specific thereto. CONSTITUTION:When the ingoing amplifier 3 and the outgoing amplifier 7 are operated due to any cause while its output level is a prescribed value or below, a modulation signal of a frequency specific to each direction is inputted to a modulation section 15 via changeover sections 12, 13 from modulation signal generating section 10 or 11. A monitor signal from a monitor signal generating section 14 is modulated by a modulation section 15 and sent to a transmission line 1a via directional couplers 16, 2. |
