基于锁相放大器的电涡流金属分类系统设计  

Design of an eddy current metal classification system based on lock-in amplifier

作　　者：张炳鑫 张志杰[1] 张泽学 Zhang Bingxin;Zhang Zhijie;Zhang Zexue(Key Laboratory of Instrumentation Science&Dynamic Measurement Ministry of Education,North University of China,Taiyuan 030051,China)

机构地区：[1]中北大学仪器科学与动态测试教育部重点实验室,山西太原030051

出　　处：《电子技术应用》2024年第12期98-104,共7页Application of Electronic Technique

摘　　要：电涡流检测是一种通过检测金属导体感应出的微小涡流信号来识别被测材料性质的方法。在利用电涡流检测技术进行金属分类时,微弱信号甚至会被噪声信号完全淹没,这使提取有效信号变得非常困难。针对这种实际问题,根据相关检测法设计了基于锁相放大器的金属分类系统。在设计中,微弱待测信号经过低噪声放大后与两路正交参考信号进行互相关,再经过低通滤波电路后被采集,对被采集的信号进行计算即可实现对微弱信号的检测。实验结果表明,系统具有较高的精度和灵敏度,能够极大地提高信号的信噪比,实现对金属材料的快速分类,分类准确率可达93%。Eddy current testing is a method of identifying the properties of a material by detecting the tiny eddy current signals induced in a metal conductor.When using eddy current testing technology for metal classification,the weak signal may be com-pletely overwhelmed by noise,making it very difficult to extract the effective signal.To address this practical problem,a metal classification system based on a lock-in amplifier was designed according to the relevant detection method.In the design,the weak test signal is amplified with low noise and correlated with two orthogonal reference signals,then collected after low-pass filtering circuit,and the collected signal is calculated to achieve detection of the weak signal.The experimental results show that this system has high accuracy and sensitivity,greatly improving the signal-to-noise ratio,achieving rapid classification of metal materials,with a classification accuracy of up to 93%.

关 键 词：AD630 相敏检波 涡流检测 锁相放大 金属分类 

分 类 号：TN722[电子电信—电路与系统]