基于希尔伯特变换的湍流随机相位差解调算法研究

Demodulating Atmospheric Turbulence Random Phase Difference Based on Hilbert Transform

根据大气光学湍流的光纤干涉测量技术原理及其信号表现形式,提出了一种基于希尔伯特(Hilbert)变换的动态相位差解调算法。数值模拟结果表明,该算法能够解调出波形相位差和符合湍流频谱特征的随机相位差,且绝对误差小于10-3,与相关法的解调结果一致。两者对比分析表明,Hilbert变换算法无需设定相关长度,对信号无平滑效应,因而能够更好地反映信号的频率特性。该研究为湍流随机相位差的检测提供了一个新方法。

An algorithm of demodulating dynamic phase difference based on Hilbert transform is proposed according to the principle and signal expression of fiber interference turbulence measurement system.The results of numerical simulation show that waveform phase difference and turbulence′s random phase difference can be demodulated by this method and absolute error is less than 10-3,which is in accordance with the results of correlation method.Compared to the correlated algorithm,the algorithm of Hilbert transform doesn′t have smooth effect on signal and doesn′t need to set correlation length,so it can reflect characteristic of signal frequency better.This research provides a new method for measuring turbulence random phase difference.