| 摘要 |
PURPOSE:To make it possible to test the operation state of a transmitter receiver even when a reflector is absent, by forming a false receiving pulse by utilizing the attenuation characteristics of the transmitter receiver. CONSTITUTION:The amplification degree of an amplifier 8 is made variable while an AND gate 16 is closed and an AND gate 19 is opened when measurement is performed by the signal of a test circuit 15. On the other hand, the gate pulse from a gate circuit 14 is imparted to the AND gates 16, 19. In testing, the gain of the amplifier 8 is increased and the output of a shaping circuit 9 is applied to FF10 through and AND gate 16 and an OR gate 17. As a result, if a transmitter receiver 5 is normal, the tail end of attenuation vibration is detected and a receiving pulse is obtained in FF10. In this case, the transmitter receiver 5 is judged as normal and, when attenuation vibration is not detected, as inferiority. By this method, the operation state of the transmitter receiver can be tested even when a reflector is absent. |
