文档介绍：脉冲涡流检测微弱信号调理电路设计
孙思成收稿日期:2012-5-16 修订日期:2012-10-15
基金项目:国家自然科学基金资助项目(51067007);江西省自然科学基金资助项目(2007GZW1530)
作者简介:孙思成(1986-),男,汉族,山东临沂莒南人,硕士研究生,研究方向为电磁无损检测:email:ssc206891@
付跃文,男,副教授,硕士生导师
付跃文
(南昌航空大学无损检测技术教育部重点实验室,南昌,330063)
摘要:本文分析了铁磁性材料脉冲涡流检测后期微弱信号的特点,在此基础上进行了脉冲涡流微弱信号调理电路的设计。设计采用了阻抗匹配、对称式限幅差分前置放大、浮空的电压源和屏蔽与接地技术,有效的提高了信号的共模抑制比和信号调理系统的信噪比。实验结果表明:设计的信号调理电路改善了接收系统的信噪比,提高了脉冲涡流晚期微弱信号的分辨能力(有效检测信号为几个微伏),实现了在复杂电磁环境下对铁磁性材料较小厚度变化的有效检测。
关键词:脉冲涡流;信号调理;信噪比;低噪声
中图分类号: 文献标识码:A 文章编号:
Design of Weak Signal Conditioning Circuit for Pulsed Eddy Current
SUN Si-Cheng ,FU Yue-Wen
(Key Lab of Nondestructive Testing (Ministry of Education, Nanchang Hangkong University),Nanchang 330063,China)
Abstract: This paper analyzed the weak late stage signal of pulsed eddy current testing of the ic materials briefly, and signal conditioning circuit was designed based on the analysis. Techniques of the impedance matching, ism shielding, grounding, floating empty DC voltage source and limited different pre-amplifying symmetrically are used and the SNR (Signal-to-Noise Rate) of signal conditioning system is improved effectively. The experiment results show that the design of weak signal conditioning circuit for pulsed eddy current improves the SNR and signal of several microvolts can be detected. Effective detection for the small corrosion of ic materials plicated ic environment is implemented.