FPGA-based control system of an ultrasonic phased array

Abstract

One of the main features of ultrasonic phased arrays is the ability to create an ultrasonic focused beam by applying time-delayed signals to each one of the elements of the array. If the focused beam can sweep a certain area it is possible to obtain a B-scan image. This process is called beamforming. In this work, a prototype control system for a phased array, based in a FPGA (Field Programmable Gate Array), was conceived. The array has 30 elements and is to be used in B-scan low resolution imaging (50 × 50 pixels). Time-delayed was implemented by means of a 50 MHz oscillator, which allows a minimum delay of 20 ns. By using nine bits counters it is possible to obtain a maximum delay of 10.24 μs between control signals. The scanning sector area is 60 mm in depth and a ±30° aperture. ©2011 Journal of Mechanical Engineering. All rights reserved.