| 摘要 |
<p>PROBLEM TO BE SOLVED: To omit a cable for monitoring by providing a reflection detector on the input side of a high frequency coaxial cable that connects two points of the input side and an output side and a high frequency relay which disconnects the high frequency coaxial cable on the output side and detecting the state of the input side by making the reflection detector detect a reflection wave signal of an input signal when the high frequency relay is disconnected. SOLUTION: When a sending and receiving amplifier 2B is normal, a high frequency relay 13 is in an on state and a sending signal is inputted to the amplifier 2B through a high frequency coaxial cable 17. If abnormality occurs in the amplifier 2B, a state detecting part 2b outputs a state detection signal 15 to a conversion circuit 16 and the circuit 16 operates a drive circuit 14 with an output pulse signal and makes the relay 13 an off operation. When the relay 13 is turned off, a sending signal is taken out as a reflection wave by a directional coupler 18 and is inputted to an inverse conversion circuit 11 through an amplifier 19 and a detector 10. The circuit 11 converts the reflection wave into a state signal and outputs it.</p> |
