中圖分類號(hào)：TN722 文獻(xiàn)標(biāo)志碼：A DOI: 10.16157/j.issn.0258-7998.245287 中文引用格式： 張炳鑫，張志杰，張澤學(xué). 基于鎖相放大器的電渦流金屬分類系統(tǒng)設(shè)計(jì)[J]. 電子技術(shù)應(yīng)用，2024，50(12)：98-104. 英文引用格式： Zhang Bingxin，Zhang Zhijie，Zhang Zexue. Design of an eddy current metal classification system based on lock-in amplifier[J]. Application of Electronic Technique，2024，50(12)：98-104.
Design of an eddy current metal classification system based on lock-in amplifier
Zhang Bingxin，Zhang Zhijie，Zhang Zexue
Key Laboratory of Instrumentation Science & Dynamic Measurement Ministry of Education，North University of China
Abstract： 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 completely 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%.
Key words : AD630；phase-sensitive detection；eddy current testing；lock-in amplifier；metal classification
