A cancellation based approach for reducing acoustic cross-talk in ultrasound arrays

Abstract

A new cancellation method is described in this paper for controlling the acoustic cross-talk in ultrasonic arrays. The array's transmit mode transfer function is represented by a transfer function matrix. Elements of this matrix are determined by exciting a single central element with an initial wideband waveform. The desired output is then defined (e.g. finite output from a single central element and zero output from all other elements). The output from the center element and its adjacent element are measured and recorded. The associated electrical excitation is also recorded. These values are used to populate the transfer function matrix. Then, the matrix equation can be solved to determine the required excitation functions on both the central array element and its neighbors. These excitation functions will result in reduced evidence of cross-talk on the output signals. Finite element analysis (FEA) simulation results produced a 9dB cross-talk reduction. Additionally, a transmitting mode experiment based on a prototype five element transducer has provided results indicating that sidelobes in the angular response can be reduced using this technique.