| 摘要 |
<p>A transducer for an ultrasonic thickness gauge of the pitch and catch type has transmitting (22) and receiving (26) transducer elements on adjoining blocks of delay material (24, 28) separated by an acoustic barrier (20) is calibrated by operating the receiving transducer element in pulse-echo mode. The lenghts of the two delay blocks (24, 28) differ by an amount calculated to make the pulse-echo travel time in the longer delay block (28) greater than pitch and catch travel time by an amount at least equal to the geometric delay of the transducer to provide an unambiguous readout during pulse-echo operation when the gauge (30) is adjusted to the proper zero point calibration for the transducer. </p> |
