| 摘要 |
PROBLEM TO BE SOLVED: To discriminate between an ultrasonic wave generated in a peripheral environment and an ultrasonic wave oscillated from an ultrasonic oscillation device. SOLUTION: A control circuit 26 constituting an ultrasonic receiving device 11 allows a memory 27 to store temporarily time information of an n-time continuous reception point-of-time t(n) when an ultrasonic wave is received in n-times continuously at prescribed time intervals corresponding to input of received information acquired from a signal determination circuit 25. A determination control means 28 determines existence of n-time continuous reception of the ultrasonic wave before the n-time continuous reception point-of-time t(n) as long as a fixed period T or before a correction period (T±α) based on reception of the ultrasonic wave. When determined that reception exists, the control means 28 determines that the reception is caused by ultrasonic oscillation from the ultrasonic oscillation device 13, and when determined that reception does not exist, the control means 28 determines that the reception is not caused by ultrasonic oscillation from the ultrasonic oscillation device 13. COPYRIGHT: (C)2010,JPO&INPIT
|
