RADIO RELAY AMPLIFIER

PROBLEM TO BE SOLVED: To make it possible to stop signal relaying when there is no signal to be relayed, and to improve an accuracy of judging whether there is any radio signal to be relayed without a necessity of controlling a change in gain of an amplifier. SOLUTION: A repeater device 1 receives a signal transmitted from a base station by means of a base station antenna 10, then amplifies the signal received by the antenna 10 by means of the amplifier 14, and then outputs the amplified signal toward a mobile station from a mobile station antenna 11. A signal detecting section 17 detects whether a downlink signal (a signal to be relayed) transmitted from the base station is contained in the signal received by the base station antenna 10 based on the output signal of the amplifier 14. A switch 16 operates according to a control signal S1 output from the signal detecting section 17, and electrically connects the amplifier 14 with the antenna 11 when the downlink signal is detected while electrically cutting off the amplifier 14 from the antenna 11 when the downlink signal is not detected. COPYRIGHT: (C)2007,JPO&INPIT