基于数字锁相放大器的微弱信号检测
首发时间:2014-06-13
摘要:锁相放大器因其中心频率稳定、品质因数高在信号检测领域获得广泛应用。在对锁相放大器检测微弱信号基本原理进行深入研究的基础上,使用虚拟仪器语言LabVIEW设计了正交矢量型数字锁相放大器,详细介绍了前面板和程序框图各组成模块的设计。使用所设计的数字锁相放大器对淹没在噪声中的待测信号进行检测实验,实验结果表明,所设计的数字锁相放大器可以从输入信号中准确提取微弱信号,检测到的信号与待测信号参数接近,频谱集中,具有较高的信噪比和较低的失真度。所设计的数字锁相放大器在保留了传统锁相放大器优点的同时具有更高的使用灵活性,在微弱信号检测领域具有较广阔的应用前景。
关键词: 微弱信号检测 数字锁相放大器 相敏检波 LabVIEW
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Weak Signal Detection Using the Digital Lock-in Amplifier
Abstract:Lock-in amplifier is widely applied in the field of signal detection due to its advantages of stable center frequency and high quality factor. After thoroughly researching the fundamental principles of weak signal detection using lock-in amplifier, a digital orthogonal vector lock-in amplifier is designed by the virtual instrument language LabVIEW. The front panel and the flow chart of the digital lock-in amplifier are presented. Furthermore, the design of each module is introduced in detail. Then, the experimental researches on detecting weak signal submerged in the noise are carried out. The results of experiments show that the presented digital lock-in amplifier can accurately extract the weak signal from input signals. The parameters of the detected signal are closely approximate to the true value. Moreover, the frequency spectrum of the detected signal is centralized. The detected signal has not only the high SNR but also low distortion. As keeps the advantages of the traditional lock-in amplifier, the designed digital lock-in amplifier possesses more application flexibility. Therefore, it is of good application prospect in fields of weak signal detection.
Keywords: weak signal detection digital lock-in amplifier phase-sensitive detection LabVIEW
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