| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a closed space monitoring system that can suitably monitor a closed space by detecting the volumetric change of the space or a change in air flow. SOLUTION: This closed space monitoring system is provided with a transmitter 11 which generates a wave of condensation and rarefaction of a gas and transmits the wave, a receiver 12 which receives the wave, and an inverting amplifier 14 which amplifies the signal from the receiver 12 through a current- voltage converting section 13. This system is also provided with an automatic gate control section 15. This system generates a standing wave in the closed space by transmitting the signal from the receiver 12 to the space from the transmitter 11 after the signal is amplified by means of the amplifier 14.</p> |
