ULTRASONIC WAVE TRANSMITTER DEVICE, ULTRASONIC WAVE PROPAGATION TIME MEASUREMENT SYSTEM AND ULTRASONIC WAVE PROPAGATION TIME MEASUREMENT METHOD

摘要

An ultrasonic wave transmitter device includes an ultrasonic wave driving circuit that modulates an ultrasonic wave based on a pseudorandom signal to generate an ultrasonic wave driving signal, and an ultrasonic wave transmitter driven by the ultrasonic wave driving signal to send out an ultrasonic wave signal of a frequency higher than a fundamental frequency of the ultrasonic wave driving signal. The ultrasonic wave transmitter includes a cylindrically-shaped piezoelectric or magnetostrictive element sending out the ultrasonic wave signal and an ultrasonic wave absorber that covers part of a base member holding the piezoelectric or magnetostrictive element.