Ultrasonic transducer

Abstract

An ultrasonic transducer is provided with an ultrasonic transmitter; an ultrasonic receiver; and a propagation-delay-time calculating device for calculating a propagation delay time from the time when an ultrasonic wave is transmitted by the transmitter until the time when the ultrasonic wave is received by the receiver. The propagation-delay-time calculating device includes: a waveform storage section in which a waveform signal of the ultrasonic wave received by the ultrasonic receiver is converted to a digital value after sampling at a predetermined timing and is stored sequentially; a virtual-zero-crossing-position detecting unit for detecting a virtual zero-crossing point on the basis of the waveform signal stored; a regression-line calculating unit or a regression curve calculating unit for estimating a zero-crossing point of the received wave by fetching from the waveform storage section waveform data at a plurality of addresses centering on an address shown by an output of the virtual-zero-crossing-position detecting unit, and by effecting a regression-line interpolation or a regression-curve interpolation with respect to the waveform data; and a propagation-delay-time calculating section for calculating the propagation delay time of the ultrasonic wave received on the basis of the zero-crossing point estimated.