基于FPGA的超声相控阵相控发射系统的研究

Research of Phased Transmission in Ultrasonic Phased Array System Based on FPGA

相控阵超声发射波束形成的关键环节是对各阵元发射相位延时进行精确控制,文中研究了基于现场可编程门阵列(Field Programmable Gate Array,FPGA)实现超声相控延时算法和相位延时控制集成的相控发射系统。分析了超声相控阵系统中线性阵列换能器相控聚焦延时算法,完成了相控聚焦算法设计并通过实验进行了验证;相控延时控制部分以数字波形发射技术为基础,研究了基于系统时钟的相控发射粗延时,延时分辨率可达15 ns;以及基于数字波形相位差的相控细延时,可达到0.35°的相位分辨率,对应250 kHz发射信号下3.75 ns的相位延时。

High-precision ultrasonic transmission phase delay is the key technology in phased array ultrasonic beams.On the basis of field programmable gate array（FPGA）,the ultrasonic phased array system,including the phase delay algorithm and the module of the phase delay control,was designed.The algorithm of linear phased arrays was analyzed and validated.And with the waveform excitation,the coarse transmission phase delay based on the system clock is 15 ns;the fine phase delay based on the digital phase can achieve 0.35°phase resolution,which equals 3.75 ns time resolution at a 250 kHz transmission frequency.