基于阶梯波参考信号的改进型正交锁定放大  

Improved orthogonal lock-in amplification based on step wave reference signal

作　　者：周逢道[1,2] 丁凯来 曾新森[1] 薛开昶[1] 孙彩堂[1,2] 

机构地区：[1]吉林大学仪器科学与电气工程学院,长春130061 [2]吉林大学国家地球物理探测仪器工程技术研究中心,长春130061

出　　处：《吉林大学学报（工学版）》2016年第3期996-1003,共8页Journal of Jilin University:Engineering and Technology Edition

基　　金：国家潜在油气资源(油页岩勘探开发利用)产学研用合作创新项目(OSR-02);吉林省科技厅发展计划重点项目(20100349)

摘　　要：对以阶梯波作为参考信号的正交锁定放大的探测精度进行了建模分析,基于硬件简单原则给出了以阶梯波作为参考信号的正交锁定放大信号检测方法的实现策略。综合考虑参考波形的失真度与采样率之间的关系,对比分析了基于面积等效法和特定谐波消去法的阶梯波合成方法。根据阶梯波参考信号对采集电路相位精度的要求及待检测信号的周期性,提出了匹配采样技术。实测结果表明：采用现场可编程门阵列（Field programmable gate array,FPGA）实现所提出的正交锁定放大,方法简单、硬件要求低、可用于识别不同异常体。改进后方法的误差为0.7%-7%,与以方波为参考信号的正交锁定放大相比,提高了探测精度。The detection accuracy of the step wave reference orthogonal lock-in amplification is modeled and analyzed,and the implementation strategy based the principle of using simple hardware is presented.Considering the relationship between the frequency waveform distortion and the sampling rate,the synthesis strategies of step wave based on equivalent area method and selected harmonic elimination method are comparatively analyzed.According to the phase accuracy requirement of step wave reference signal acquisition and the periodicity of the signal to be tested,a matching sampling technique is proposed.Experiments results show that the proposed orthogonal lock-in amplification can achieved by Field Programmable Gate Array（FPGA）,and the method is simple and has low hardware requirement,can be used to identify different anomaly bodies.The error of the improved method is 0.7%to 7.0%.Compared with the square wave reference orthogonal lock-in amplification,the detection accuracy is improved by the new method.

关 键 词：信息处理技术 近地表 正交锁定放大 阶梯波 

分 类 号：TH763.1[机械工程—仪器科学与技术]