| 摘要 |
PURPOSE:To simply and easily attain self-decision by generating a test signal of a same frequency so as to detect a fault at the reduction in a reception signal. CONSTITUTION:A reception signal from an antenna 4 is inputted to a synthesis circuit 11. When a warning device 10 raises an alarm attended with a preset fault such as a reduction of a reception output signal or the like, the maintenance personnel operates a test wave generating circuit 12 by switch operation and a same test signal of a frequency as that of the reception frequency is inputted to the synthesis circuit 11. When the reception signal obtained by a demodulator 9 is normal in this state, since the circuits after the synthesis circuit 1 are decided normal. Then the transmitter and the transmission system are checked. |
