An Improved Hardware System of Excitations Pulse on X-Waves with Direct Digital Synthesizer

Abstract

Limited diffracting waves such X-wave have great potential applications in the enlargement of the field depth in acoustic imaging systems. In practice, the generation of real time X-wave ultrasonic fields is a complex technology which involves precise and specific voltage for the excitations for each distinct array element. In order to simplify hardware system of excitations pulse in X-wave, the complex excitations were instead by simple driving, which combination of rectangular and triangular driving pulses. The improved hardware system consists a computer for communication with the circuit, universal serial bus (USB) based micro controller unit (MCU) for data transmission, field programmable gate array (FPGA) based Direct Digital Synthesizer (DDS), 12-bit digital-to-analog (D/A) converter and a two stage amplifier. DDS generate arbitrary waveforms with a single, fixed-frequency reference clock, which satisfy the need of complex excitations pulse of X-wave. From the simulations of hard system, the difference of waveforms at different radius between theoretical waves is reduced in 0.41%.