锁相放大技术提取微弱信号的极限性能仿真与分析  

Simulation and analysis of limitation performance of lock-in amplification technology on weak signal extraction

作　　者：杜海伟 朱思源 龙江 刘君威 吕金 DU Haiwei;ZHU Siyuan;LONG Jiang;LIU Junwei;LÜ Jin(School of Measuring and Optoelectronic Engineering,Nanchang Hangkong University,Nanchang 330063,China;MOE Key Laboratory of Nondestructive Testing,Nanchang Hangkong University,Nanchang 330063,China)

机构地区：[1]南昌航空大学测试与光电工程学院,江西南昌330063 [2]南昌航空大学无损检测技术教育部重点实验室,江西南昌330063

出　　处：《现代电子技术》2023年第3期52-56,共5页Modern Electronics Technique

基　　金：国家自然科学基金项目(12064028);无损检测技术教育部重点实验室开放基金(EW202108218)。

摘　　要：锁相放大技术是一种基于频谱搬移原理,能够从干扰极大环境中提取出特定载波频率信号振幅的技术。该技术以提取信号的高信噪比、高精确度等优点被广泛应用于混杂于背景噪声中的微弱信号幅值的提取。文中利用Simulink仿真研究了锁相放大技术从较强的背景噪声中提取微弱信号的极限性能的特性,采用均值与偏离度判断信噪比的极限范围,并通过改变仿真模块参数,包括积分时间、信号与噪声的功率比与振幅比、噪声类型等,详细分析了提取微弱信号的信噪比极限范围。研究结果显示,对于含均匀高斯噪声的信号,提取微弱信号的信噪比极限为-52.04 dB;对于含白噪声的信号,提取的信噪比极限为-49.03 dB。该研究对使用锁相放大技术对微弱信号的实际测量有很好的理论参考意义,对分析基于锁相放大技术的测量系统的整体信噪比有一定的帮助。Lock-in technology is the one based on the principle of frequency spectrum drift to extract the amplitude of a particular carrier frequency signal from a highly interfering environment.Because the weak signals that need to be extracted in the actual measurement are often submerged within the noise,this technique has been widely used to extract weak signal amplitude with the advantages of high signal-to-noise ratio and high accuracy.In this paper,Simulink is used to study the lockin amplification technology′s characteristics of the extreme performance of extracting weak signal from the strong background noise to judge the signal-to-noise ratio limitation by the mean value and the deviation,and analyze the law of extracting the signal-to-noise ratio limitation of weak signal in detail by changing the simulation parameters(including the integral time,the power ratio and amplitude ratio of the signal to the noise,and the noise types).The results show that,as for the signal containing Gaussian noise,the limitation of the signal-to-noise ratio of the extracted weak signal is 52.04 dB,and as for the white noise,the limitation of the signal-to-noise ratio of the extracted weak signal is 49.03 dB.This study has the theoretical reference significance to perform the actual measurement of weak signals by lock-in amplification technology,and is helpful for analyzing the overall signal-to-noise ratio of the measuring system based on the lock-in amplification technology.

关 键 词：锁相放大 极限性能 弱信号提取 仿真参数设置 信噪比分析 测量系统 

分 类 号：TN911.7-34[电子电信—通信与信息系统]