Characterization of wideband ultrasonic transducers using pulse preshaping

A high speed digital to analog converter was used to generate Gaussian pulses of various half-widths. These were amplified and used to excite wideband commercial ultrasonic transducers of different nominal frequencies. The ultrasonic beam was reflected off a flat smooth surface orthogonal to the beam and at a known distance. The experiment was done in pulse-echo mode and used the same transducer as a receiver. These reflected waveforms were analyzed and a model was proposed for wave generation and propagation. The spreading and symmetry predicted by the model were observed to occur.