| 摘要 |
PURPOSE:To conduct the test for each section of a receiver without any measuring instrument by using a signal being the result of passing an output of a transmission mixer through a reception side filter as a test signal in a transmitter-receiver using a local oscillation section in common for the transmission and reception. CONSTITUTION:A local oscillator 3 is used in common for a transmission system 1 and a reception system 2. In the case of diagnosing a fault of the reception system 2, a switch 7 is turned on and an output signal of a transmission system mixer 4 is inputted to a filter circuit 5 for eliminating the transmission frequency of the reception system 2. The output signal of the filter circuit 5 is used as a test signal to check the signal level of each section of the reception system 2. Thus, the reception system is diagnosed without using any measuring instrument even in the absence of the reception input. |
