基于电子开关式锁相放大器的微弱信号检测方法

发布时间：2018-01-21 17:07

本文关键词： 微弱信号锁相放大器移相器相敏检波　出处：《重庆师范大学学报(自然科学版)》2016年06期 　论文类型：期刊论文

【摘要】：在磁感应成像系统中,有用的二次磁场十分微弱,都淹没在主磁场中,因此采用微弱信号检测技术中的锁相放大器来提取。本研究以电子开关为相敏检波核心,利用相敏检波、锁相环、直流放大滤波、AD采样等电路模块,构成了精度高的模拟锁相放大器。该系统检测有效值10~1 000μV频率为1kHz的正弦信号,其误差在2.6%以内;输入相同幅值频率为1.05kHz的噪声信号,其误差最大在3%以内;输入10倍幅值1.05kHz的噪声信号,对测量结果有一定影响,其误差最大8.6%。所以,基于电子开关式锁相放大器有很好的噪声抑制能力,能够在强噪声背景下提取出特定频率微弱信号。
[Abstract]:In the magnetic induction imaging system, the useful secondary magnetic field is very weak, which is submerged in the main magnetic field, so the phase-locked amplifier in the weak signal detection technology is used to extract. In this study, the electronic switch is the core of phase-sensitive detection. The circuit modules are phase-sensitive detection, phase-locked loop, DC amplifier filter and AD sampling. An analog phase-locked amplifier with high precision is constructed. The system detects sinusoidal signals with a RMS of 10000 渭 V and 1 kHz, and the error is less than 2.6%. The maximum error of the noise signal with the same amplitude frequency of 1.05kHz is less than 3%. The input 10 times amplitude 1.05kHz noise signal has certain influence to the measurement result, its error is the biggest 8.6. Therefore, based on the electronic switch type phase-locked amplifier has the very good noise suppression ability. It can extract the weak signal of specific frequency in the strong noise background.
【作者单位】：重庆师范大学物理与电子工程学院;
【基金】：国家自然科学基金(No.51507023) 重庆市教委科学技术研究一般项目(No.KJ130616)
【分类号】：TN911.23
【正文快照】： 随着现代科学技术的发展,在许多领域需要测量物理量的微弱变化。例如:微弱电压或电流、微弱磁场、微弱压力、微弱电感、微弱电容、微弱声音和微弱的光等[1]。由于这些微小量的变化通过传感器转换成的电信号十分微弱,可能是毫伏、微伏、纳伏级别,甚至更小。在强噪声背景下微弱

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