摘要微弱信号检测技术是随着工程应用不断发展的,用于检测强噪声背景中微弱信号的一门新兴的技术学科。随着社会及科技的发展,微弱信号检测技术已经在物理、化学、天文、生物、医学以及多种工程应用领域得到了相当广泛的应用。与此同时,用于检测微弱信号的装置也逐渐地发展壮大起来,而数字锁相放大器以其低功耗、高可靠性等突出特征已成为当前微弱信号检测的重要装置,目前已广泛应用于军事国防、家用电器、网络通讯、工业控制等领域。 本论文系统选用了TI公司DSP的芯片TMS320F2812为核心进行系统设计。结合数字锁相放大器的相关检测原理,给出了整体设计方案,着重从相关检测原理算法和查表法的软件实现进行了详细分析,并对相关算法进行了MATLAB仿真,对比了不同信噪比条件下检测出的有用信号的质量,验证了算法可行性后,利用C语言编程实现了以DSP芯片为核心的算法设计。68451

毕业论文关键词：微弱信号检测；DSP；数字锁相放大器

毕业设计说明书（论文）外文摘要

Title    Design of digital lock-in amplifier based on DSP             

Abstract

  Weak signal detection technology is with the development of engineering application, used for detection of weak signal in strong noise background, a new technology of discipline. With the development of society and science and technology, the weak signal detection technology has been in physics, chemistry, astronomy, biology, medicine, and a variety of engineering applications has been quite widely used. At the same time, used to detect weak signal device also gradually grow up, and digital phase-locked amplifier with its outstanding characteristics such as low power consumption, high reliability has become the important device of weak signal detection, currently has been widely used in military defense, home appliances, network communications, industrial control and other fields. System this paper USES TI company DSP chip TMS320F2812 as the core of the system design. Related detection principle of digital phase-locked amplifier, the overall design scheme is given, emphatically from the principle of correlation detection algorithm and look-up table method of software realization are analyzed in detail, and the related algorithm by MATLAB simulation, compares the different SNR detect the quality of the useful signal, after the feasibility of this algorithm was verified, using C language programming to realize the algorithm design of DSP chip as the core.

Key words: weak signal detection; DSP; Digital phase-locked amplifier

1  绪论

1.1背景

  随着光电技术和传感技术的飞速发展，经常会遇到对微弱信号进行检测的问题，难以检测，这就迫切需要一种微弱信号的检测技术。传统的信号检测手段，无法达到从强噪声中分离微弱信号的目的。在信息论和随机过程理论研究的基础上，利用噪声与被测信号不相干的原理，研制出从噪声中提取微弱正弦信号的仪器，称为锁相放大器。根据相敏检波器的实现方式不同，可以分为模拟锁相放大器和数字锁相放大器。而数字锁相放大器由于采用了现代数字信号处理先进技术，以及数字信号处理器的优势，极大的提高了锁相放大器的测量精度，主要优点有低功耗、高可靠性，是锁相放大器的发展趋势。数字锁相放大器是一种用数字信号处理的方式实现的相敏检波器（或同步解调器解调器）来构成的锁相放大器，数字锁相放大器比模拟锁相放大器有许多突出的优点而倍受青睐，成为现在微弱信号检测研究的热点。