| 摘要 |
PROBLEM TO BE SOLVED: To reduce the number of parts required for a reflective power detecting device provided at an amplifier apparatus. SOLUTION: An output signal of an amplifier 2 is transmitted as a radio signal from an antenna 6 via an isolator 31 of a reflective power detecting circuit 3 and an antenna input end 6a. A reflective wave from the input end 6a is absorbed in a dummy resistor, provided at the isolator 31 to be converted into heat. A temperature-detecting circuit 32 detects the temperature of the dummy resistor, to supply the detected temperature value to a determining circuit 5 as a voltage value. A deciding circuit 5 compares the voltage value supplied from the temperature detecting circuit 32 with a predetermined threshold voltage and outputs an alarm signal to a control circuit 4, if the former is greater than the latter. Upon the receipt of the alarm signal, the control circuit 4 decreases the gain of the amplifier 2 or stops output of the amplifier 2, to reduce the output power of from the amplifier 2. COPYRIGHT: (C)2004,JPO
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