| 摘要 |
PURPOSE:To lessen the probability of malfunctions especially remarkably with respect to an object detecting device where ultrasonic pulse are transmitted from an ultrasonic wave transmitter to a prescribed space and reflected waves are received by an ultrasonic wave receiver to detect the existence of an object to be detected. CONSTITUTION:An ultrasonic pulse signal (c) generated by one shot circuit 6, and OSC1 7, and an OSC2 8 is applied to an ultrasonic wave transmitter 2 through a driving circuit 4 and is transmitted to a prescribed space. When an object 1 to be detected is put in a detection range set by a timing circuit 12, a reflected ultrasonic wave signal is received by an ultrasonic wave receiver 3 and is amplified by an amplifying circuit 10 and is outputted and is inputted to one input of an AND gate circuit 11. The output of the circuit 11 is inputted to a comparing circuit 13 and is compared with a reference signal; and if the level of the output of the circuit 11 is higher than that of the reference signal, the comparing circuit 13 issues the output to operate an FF1 14. |
