基于HHT的宽带幅度非平稳调制信号的特征提取  

Feature extraction from non-stationary ampltitude modulated broad-band signal using the Hilbert-Huang Transform

作　　者：罗昕炜[1] 方世良[1] 

机构地区：[1]东南大学水声信号处理教育部重点实验室,南京210096

出　　处：《信号处理》2011年第6期950-955,共6页Journal of Signal Processing

基　　金：国家重大基础研究项目(6131222)

摘　　要：宽带调制信号在调制源的工作状态产生变化时,信号的调制频率、调制深度随时间变化,传统DEMON解调制方法难以获取短时变化的调制特征。本文针对非平稳调制特点,利用Hilbert-Huang Transform(HHT)数据自适应特性和高分辨率的时频分析能力以及数学形态滤波器(MMF)对信号的降噪性能,提出了一种利用HHT提取宽带幅度调制信号的调制特征方法(MH_DEMON)。MH_DEMON方法通过MMF对调制信号的包络曲线进行预处理,使之在时域波形上更加光滑;然后利用经验模态分解(EMD)方法将信号分解成各阶本征模态函数(IMF),最后利用IMF的Hilbert变换谱,提取各个时刻的目标瞬时调制频率。仿真数据和螺旋桨噪声数据的实验分析表明,与传统方法相比,MH_DEMON方法能有效提取非平稳宽带幅度调制信号的调制特征,为目标调制源分类识别和运动状态分析提供了支持。When working status of modulation source changes with time,the conventional DEMON（Dectecion of Envelope Modulation on Noise） method is difficult to extract the modulation characteristics from the modulated signal in short time,including modulation frequency or modulation depth.For non-stationary modulation characteristics,using Hilbert-Huang Transform（HHT） data adaptive features and high-resolution time-frequency analysis capabilities as well as mathematical morphology filter（MMF） on the signal noise reduction performance,a modified method＂MH_DEMON＂based on HHT and MMF is given.Firstly,a signal filtering using MMF on the modulation envelope curve signal is performed to make the signal more smooth.Then,the empirical mode decomposition（EMD） method is adopted to decompose the signal into several the intrinsic mode function（IMF）,Finally,the Hilbert transform spectrum（HS） of IMF is computed,and instantaneous modulation frequency is extracted from the IMF＇s.HS.The result of simulation data and propeller noise data shows that,the MH_DEMON can extract non-stationary broadband amplitude modulation characteristics effectively.And comparing with the conventional method,the performance of the proposed method is better in processing short-time signal which is modulated by non-stationary source.The proposed method could provide support in both modulation source classification and motion analysis.

关 键 词：HHT 解调 经验模态分解 调制特征 数学形态滤波 

分 类 号：TN911.3[电子电信—通信与信息系统]