基于广义谐波小波变换的布里渊光时域反射计的数字包络解调技术  

Digital Envelope Detection Technique for Brillouin Optical Time-Domain Reflectometry Based on Generalized Harmonic Wavelet Transform

作　　者：杨巍[1] 杨远洪[1] 

机构地区：[1]北京航空航天大学仪器科学与光电工程学院光电工程系,北京100191

出　　处：《光学学报》2013年第5期38-46,共9页Acta Optica Sinica

基　　金：国家863计划(2006AA06Z216)资助课题

摘　　要：分析了相干探测型布里渊光时域反射计(BOTDR)的信号特征及信号包络对其空间分辨率和布里渊频移测量精度等参数的影响,总结了幅度调制信号的数字包络解调算法模型和理想的数字包络解调算法的特性。根据广义谐波小波(GHW)的零相移理想带通滤波特性及通带参数可灵活设计的特点,提出了一种基于广义谐波小波变换(GHWT)的BOTDR的数字包络解调技术,设计了解调方案并进行了参数优化和实验研究。结果表明,与现有BOTDR数字包络解调技术相比,所提出的新技术能够无失真地提取BOTDR的信号包络并具有较强的噪声抑制能力,从而在不影响BOTDR的空间分辨率的情况下提高布里渊频移测量精度。最后,还根据解调算法的频域特性对实验结果进行了分析。The signal characteristics of the coherent heterodyne Brillouin optical time-domain reflectometry （BOTDR）, as well as the impacts of the signal envelope on the spatial resolution and Brillouin frequency shift （BFS） measurement accuracy of the BOTDR are analyzed, respectively. A general algorithm model for the digital envelope detection of an amplitude-modulated （AM） signal and the features of an ideal digital envelope detection algorithm are summarized, respectively. According to the zero phase shift ideal bandpass filtering features and passband designing flexibility of the generalized harmonic wavelet （GHW）, a digital BOTDR envelope detection technique based on the generalized harmonic wavelet transform （GHWT） is proposed, and the envelope demodulation scheme is designed. The parameters optimization and experiments are made. The results show that, compared with the existing techniques, an undistorted signal envelope with a higher signal-to-noise ratio can be obtained by the proposed method, resulting in an undegraded spatial resolution and a higher BFS measurement accuracy for the BOTDR system. The experimental results are also analyzed according to the frequency domain characteristics of the algorithms.

关 键 词：传感器 光纤传感 布里渊光时域反射计 广义谐波小波变换 包络解调 

分 类 号：TN247[电子电信—物理电子学]