| 摘要 |
PURPOSE:To facilitate a drastic reduction in the measuring time by emitting interrogation signals simultaneously to first and second sound wave responders from a sound wave transmission/reception measuring apparatus. CONSTITUTION:When interrogation signal frequencies f0 and fx are emitted simultaneously to first and second sound responders 12 and 21-23 from a sound wave transmission/reception measuring apparatus 11, the devices 21-23 receive the frequency fx and emits sound waves of frequencies f1, f2 and f3 in response thereto. On the other hand, the device 12 receives the frequency f0 and emits a sound wave of the frequency fx in response thereto. The sound wave is received with the device 11 while done with the devices 21-23, which emit sound waves of frequencies f1-f3 in response thereto and these sound waves are received with the device 11 again. Therefore, the apparatus 11 calculates the distance between the apparatus 11 and the device 12 from a time difference between the time of oscillating the frequency f0 and the time of receiving the frequency fx, and the intervals between the apparatus 11 and devices 21-23 from the time difference between the time of oscillating the frequency fx therewith and the time of receiving the frequencies f1-f3 therewith to determine the distance. Thus, the measurement of level is enabled. At this point, the reduction in the measuring time is made possible by transmitting the interrogation frequencies f0 and fx simultaneously from the apparatus 11. |
