一种基于多重相敏解调算法的相位差测量新方法

New Method for Phase Difference Measurement Based on Multi-layer Phase Sensitive Detection Algorithm

研究了一种新的测量正弦信号相位差的方法,就是利用正弦信号的特殊性质,通过多次信号相敏解调运算,能够检测信噪比很低的两路正弦信号之间的相位差,分别讨论了信号的信噪比、取样点数、A/D的量化位数对测量结果的影响,并给出了具体的仿真结果。在低信噪比情况下与传统的互相关法进行比较,并给出实验数据,结果表明这种方法能有效地提取出被噪声严重污染的信号的相位差,而且算法简单,物理意义明确,精度可以满足工程的要求,具有检测能力强的优点,特别适合极低信噪比甚至负信噪比情况下的相位差的高精度测量。

A new method for phase difference measurement is introduced in this paper.Because the sinusoidal signal has a particular trait,it is possible to detect the phase difference of two unknown weak signals in powerful noise by multi-layer phase sensitive detection algorithm.Length of sampled data,signal-noise ratio and number of ADC quantization bits which influence precision of phase difference measurement are particularly discussed and analyzed.Simulation results and conclusions are given.The simulations proves its feasibility and effectiveness to detect the phase difference.Compared with cross correlation method,this method can be widely used because it has many virtues such as simple theoretic deduction and explicit physical signification,and it can satisfy the requirement of engineer.It is especially fit for low signal-noise ratio condition or negative signal-noise ratio condition and it can get high resolution.