基于小波变换的干涉信号包络提取方法研究

Interference Signal Envelope Extraction Based on Wavelet Transform Method

摘要:

为了实现对宽谱光源自相干函数的测量, 必须对宽谱光源干涉信号的包络进行提取。因此, 宽谱光源干涉信号包络的提取就成为了测量光源自相干函数的关键因素。针对现有的包络解调方法的不足, 建立了基于复Morlet小波的干涉信号包络提取方法。该方法采用复Morlet小波作为母小波, 通过选择适合尺度参数和位置参数, 可以有效地提取干涉信号的包络并具有良好的抗噪能力; 利用计算机Matlab仿真证明了该方法的有效性; 最后利用该方法对韩国Fiber Pro公司的白光干涉仪干涉输出信号进行包络提取,动态范围达到-60 dB。

Abstract:

In order to realize the measurement of coherence function of wide spectrum light source, the envelope of interference signal of the broad spectrum light source must be extracted. Thus the envelope extraction becomes the key factor for the measurement of coherence function. In consideration of the disadvantage of envelope demodulation, the interference signal envelope extraction was established based on wavelet transform method. It adopts the complex Morlet wavelet as mother wavelet which can extract the interference signal envelope effectively and has a good ability to resist noise by choosing a suitable scale parameter. Using the Matlab computer simulation prove the effectiveness of this method. Finally, the output signal’s envelope of Fiberpro company’s white light interferometer was extracted with this method and the dynamic range can reach -60 dB.