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High-voltage amplifier with DC adaptive capability for piezoelectric acoustic transmitter/actuator

Niebergal J., Caputa K., Zielinski A.

Hydroacoustics

2012

Vol. 15

153-162

The piezoelectric element of an acoustic transducer requires a high voltage drive signal. This paper describes the development of a compact high-voltage amplifier (HVA) capable of driving piezoelectric elements and providing the additional capability of a DC response. This opens the possibility to control the DC displacement of an active array of transducers, which would not be possible using a step-up transformer due to the lack of a DC response. This HVA is particularly suited for low frequency operation, where the elimination of the transformer will provide the greatest benefit due to its large size, cost and weight at these frequencies. The HVA is very compact allowing large-scale integration, and therefore can be utilized for driving large arrays of transducers. Such an array could facilitate an active correction system driven by the DC signal from the amplifier. Considering the target application for large multi-element transducer arrays, design goals have been to minimize the size and cost. The features and benefits of the HVA will be presented.

From deformable mirror pointing at sky to underwater acoustics

Niebergal J., Zielinski A., Caputa K.

Hydroacoustics

2011

Vol. 14

171-180

Due to air density variations, turbulence, eddies, and cross winds in the atmosphere, ground-based telescopes record temporal and spatial fluctuations of phase and amplitude of received stellar light. For astronomical imaging, the effects of the atmosphere result in aberrations of received light leading to blurring and other undesired affects. Using a complex optical system called adaptive optics, aberrations can be effectively reversed resulting in improved imaging quality. Similarities between the atmosphere and ocean are apparent when considered as a propagation medium for light or sound, respectively; both media are turbulent and governed by similar dynamic processes involving temperature gradients, pressure differentials, and other factors. Similarities also exist in the distortions that the changing medium produces on each wavefront. In presenting the adaptive optics solution that has improved ground-based astronomical imaging, this paper will propose that similar strategies could be utilized in underwater acoustics.