| 摘要 |
PURPOSE:To detect an acoustic signal with high sensitivity, and also, to easily replace an acoustic microphone at the time when it has become a fault by containing the acoustic microphone in a spare tank through a valve. CONSTITUTION:A spare tank 11 contains a sound collecting device 12 of a parabolic type and an acoustic microphone 13 which has been attached to a sound collecting part, in the inside. Also, the spare tank 11 is connected to a tank 1 through a valve 14, and as for the spare tank 11, at least one piece of more are attached to the tank 1. Moreover, the valve 14 always remains open by, for instance, a sluice valve, etc. In this state, an output of the acoustic microphone 13 is connected to an amplifier 16 and a signal adder 17 through a pressure connector 15. When an output of a current pulse detector 8 is outputted to a trigger device 18, the signal adder 17 is started by a signal of the trigger device 18and adds an acoustic signal. The signal which has been added is displayed 19. In such a way, the acoustic signal is detected with high sensitivity, and also, the acoustic microphone can be replaced easily at the time when it has become a fault. |
