Two-stage sinusoidal generator with calibration and pulse train amplitude feedback for ultrasonic applications

Ultrasonic applications require precise knowledge of the dispatched wave in order to process the returning signal. In this work, a cost effective two stage resonant sinusoidal source is presented, capable to adjust on demand both frequency and amplitude of the sinusoidal output. The source tunes automatically to the load parameters using pre-calibration, and is able to drive a range of different piezoelectric sensors. A unique feature is an additional feedback loop that adjusts the amplitude during pulsing and compensates for temperature related parameter drift of the load over long pulsing periods. Design considerations and control implementation are discussed. Experimental validation is carried out on a 20 W laboratory prototype.