| 摘要 |
PURPOSE:To secure the monitor for the transmitter/receiver of the base station from a remote place without installing any special monitor device at the radio base station. CONSTITUTION:Transmitter/receiver of the radio base station is connected to control unit 2 provided at the remote place via four pieces of wires 3-6. With application of transmission control signal SC, transmission oscillator 11 operates and the output level detection signal WTX is applied to comparator 28 via the transmitter comprising modulator 12, multiplier 13, power amplifier 14 and transmission output detector 15 each. On the other hand, oscillation control circuit 19 actuates reception monitor oscillator 20 for a fixed time. And the output signal is applied to receiver consisting of coupling circuit 21, high frequency amplifier 22, mixer 23, local oscillator 24, intermediate frequency amplifier 25, detector 26 and aural amplifier 29 each. Then intermediate frequency level detection signal WRX passed through detection circuit 27 is applied to comparator 28. Control circuit 34 monitors the normalcy of the transmitter and the receiver via the output of comparator 28. |
