超声相控阵系统中高精度相控发射的实现  

High-precision phased ultrasonic transmission in phased array ultrasonic systems

作　　者：鲍晓宇[1] 施克仁[1] 陈以方[1] 张伟[1] 

机构地区：[1]清华大学机械工程系,北京100084

出　　处：《清华大学学报（自然科学版）》2004年第2期153-156,共4页Journal of Tsinghua University(Science and Technology)

基　　金：国家教育振兴计划项目(081100501)

摘　　要：相控阵超声发射波束形成中的关键环节是对各阵元的发射相位延时进行精确控制。提出了一种新颖的高精度相控发射电路,它采用波形激励方式,通过D/A转换器将任意复杂的数字波形转换成模拟信号,经放大驱动后激励各阵元发射超声。以波形激励为基础,采用D/A输出时钟和直接数字频率合成(directdigitalsynthesis,DDS)技术相结合的方法实现了高精度的发射相控延时。基于D/A输出时钟的相控发射粗延时分辨率为15ns。基于DDS的相控发射细延时可达到1.41°的相位分辨率,对应3.096MHz发射信号下1.25ns的相位延时。实验表明,该相控发射电路能够达到很高的相控发射精度。High-precision ultrasonic transmission phase delay is the key technology in phased array ultrasonic beams. This paper describes a high-precision phased ultrasonic transmission circuit designed using the waveform excitation method. An arbitrary digital waveform is converted to analog signals through the D/A, and then amplified to excite the transducer elements for the ultrasound transmission. With the waveform excitation, the D/A update clock is combined with DDS (direct digital synthesis) to obtain a high-precision transmissions phase delay. The coarse transmission phase delay based on the D/A clock is 15 ns. The fine phase delay based on the DDS can achieve 1.41° phase resolution, which equals 1.25 ns time resolution at a 3.096 MHz transmission frequency. Experimental results show that the circuit provides very high phased ultrasonic transmission precision.

关 键 词：超声相控阵 高精度相控发射 无损探伤 相位延时 超声检测系统 

分 类 号：TG115.285[金属学及工艺—物理冶金] TB553[金属学及工艺—金属学]