基于双相锁相放大器的微弱信号矢量测量

噪声存在于任何一个系统中,当所要检测的信号比较微弱且淹没在强噪声背景中时,用传统的检测方法检测信号非常困难,因此如何把淹没于强噪声中的有用信号提取出来的问题越来越引起人们的关注。该文采用时域检测方法,利用移相技术得到相互正交的参考方波信号,通过互相关算法,完成了正交矢量型LIA相关器的实现,利用该方法实现了对微弱信号幅值和相位的检测,有效地抑制了干扰,提高了系统的性能。

The vector Measuring of Weak Signal Based on Dual-Phase LIA

Noise exists in all systems, especially it is difficult to detect weak signal in strong noise based on conventional ways ,so more attention has been paid to the problem of how to measure the weak signal in strong noise .The principle and process of detect- ing weak signal by using Lock-in amplifier are discussed in details in the paper .Two orthogonal square waves as referential waves are got by hardware phase shift.and realized an orthogonal vectors LIA by using cross correlation algorithm.It is effective on restraining noise to get amplitude and phase of weak signal in noise.