Technique for generation of unipolar ultrasonic pulses

A transmit-receive switch has been developed that permits the generation and detection of broadband unipolar ultrasonic stress pulses in a pulse-echo mode. Results obtained with conventional planar transducers show that the bandwidths obtained are significantly larger than those realized with conventional ultrasonic pulse-echo techniques. The broadband technique is expected to be applicable to flaw sizing problems encountered in nondestructive evaluation (NDE) and to the measurement of gradients in material properties that can be related to changes in the acoustic impedance.<>