摘要在科学研究和工程实践中，经常需要检测毫微伏量级的微弱信号和受到外界噪声干扰的信号，这都归结于对微弱信号的处理。它是运用电子学和信息论等学科知识，分析噪声产生的原因和规律，研究被测信号和噪声的差别以达到检测被背景噪声覆盖的微弱信号的目的。64985

本文在介绍传统微弱信号检测的基础上，详细阐述了噪声、微弱信号检测的有关理论。根据实际应用系统中的干扰噪声的来源和特点，提出了基于锁定放大器的检测模型，，对检测系统进行了总体设计和各分模块硬件设计，并对各功能模块进行了理论。该电路在Multisim10仿真软件中进行模拟仿真。文章最后对不同幅度的信号源的检测结果进行详细分析，结果发现此电路设计能够较好的消除噪声，检测到微弱信号。

毕业论文关键词  微弱信号检测锁定放大器乘法器仿真

毕业设计说明书（论文）外文摘要

Title  Weak signal detection circuit design

Abstract In the engineering practice of researching phenomena and rules of nature, weusually need detect very small signal, which is a new technology called weak signaldetect in signal detect field. This is an integrated technology based on electronics, information theory, physics and computer science. Weak signal detect is a technologyscience based on characteristics andcorrelation between the noise and signal, whichcan pick up signal from strong noise background.

This article elaborates related theory about noise and weak signal detection which based on the introduction of the traditional weak signal detection. According to the source and characteristic of the interfering noise in practical application system, a detect model which based on  lock-in amplifier is proposed , and the detection system is carried on integrated design and each module hardware design. This paper also demonstrate each function module. The simulation of the circuit is proceeded in the Multisim10 simulation software. The paper analyzes the test consequences of the different amplitude signals. And the result shows that this circuit is designed to eliminate noise and to detect weak signals perfectly.

KeywordsWeak signal detectionLock-in amplifierMultiplier Simulation

目   次

1 绪论 1

1.1 研究微弱信号的意义 1

1.2 微弱信号检测概述1

1.3 仿真软件简介5

1.4 本文完成的主要工作6

2  锁定放大原理及其应用 8

2.1  概述 8

2.2  相敏检测  8

2.3  锁定放大器的组成与部件 9

2.4  锁定放大器的性能指标及动态协调11

3  硬件分析 13

3.1  总体方案设计13

3.2  各模块电路设计13

3.3  理论分析与计算16

4实验仿真与结果 18

4.1电路图的输入18

4.2电路仿真18

4.3实验结果分析18

结论  25

致谢 26

参考文献27

附录A  总体电路原理图 29

1  绪论

1.1 研究微弱信号检测的意义

微弱信号检测技术在许多领域具有广泛的应用，例如物理学、化学、电化学、生物医学、天文学、地学、磁学等。微弱信号检测所针对的检测对象，是用常规和传统方法不能检测到得微弱量，例如弱光、弱磁、弱声、小位移、微流量、微震动、微温差、微压差以及微电导、微电流等。随着科学技术的发展，越来越需要把深埋在噪声中的微弱信号检测出来。可以说，微弱信号检测是发展高新技术、探索及发现新的自然规律的重要手段，对推动相关领域的发展具有重要意义。论文网