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Time-vary Signals Detect And Instantaneous Frequency Estimate Technique Study

Posted on:2008-05-12Degree:MasterType:Thesis
Country:ChinaCandidate:X J HuFull Text:PDF
GTID:2178360212978604Subject:Signal and Information Processing
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The method of analyze and process signal is Fourier transform in traditional signal processing. The world that have the character of non-stationary system dominated by 'non-' family: non-stationary, non-linear, non-gauss, non-continuous, non-periodic, etc. The classic method based on Fourier transform helpless for it. So analyze non-stationary time-vary signal need develop new theory and means. This dissertation bring forwards some kinds of detection and instantaneous frequency estimation methods based on analysis of time-vary signals in a systematic and all-round way. The main contributions are as follows:(1) The basic theories of time-vary signal processing are introduced systemicly and summarily. The several methods time-frequency analysis and performaces of them are showed and the processing techniques of time-frequcency results are disussed.(2) The detection problems of single-component linear frequency modulation (LFM) signal are studied. Three motheds are showed; they are Wigner-Ville Distribution-Hough (WVD-Hough), Smoothed-Pseudo-Wigner-Ville Distribution-Hough (SPWVD-Hough), and Reassign-Smoothed-Pseudo-Wigner-Ville Distribution- Hough (RSPWVD-Hough). The mothed of improved WVD-Hough is brought forward. This method can reduce operation time and enhance detection capability in the condition of low signal-noise ratio (SNR). The detection performances about different methods are given through analysis and comparison.(3) The instantaneous frequency estimation problems of single-component LFM signal are studied. The methods include WVD maximum, SPWVD maximum, WVD-Viterbi, and SPWVD-Viterbi. The motheds of improved WVD maximum and improved WVD-Viterbi that can mend estimation performance in low SNR condition are brought forward. The estimation performances about different methods are given through analysis and comparison.(4) The instantaneous frequency estimation problems of multi-component LFM signal are studied from two facts of instantaneous frequency's intersecting or not. First, stepwise expurgation thinking is used directly to extinguish instantaneous frequency...
Keywords/Search Tags:time-frequency, linear frequency modulation signal, cross-term, Wigner-Ville distribution, instantaneous frequency, linear fitting
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