Improved Algorithms of the Adaptive Polynomial Wigner Distribution and Their Applications
| Autor: | Chien-Yu Li, 李建裕 |
|---|---|
| Rok vydání: | 1999 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 87 The Wigner-Ville Distribution (WVD) has high resolution for monocomponent and linear FM Signals, but it has severe cross-term interference. The short-time Fourier Transform (STFT) dose not have cross-terms problem, but it has bad resolution. The polynomial WVD (PWVD) and higher order LWD are proposed to resolve the optimal energy concentration of WVD for processing higher order nonlinear FM signals. In order to avoid cross-term interference, we use STFT to established PWVD and LWD, and it results in modified PWVD and modified LWD. However, for noisy nonstationary signals, the modified algorithms still can not get high resolution. To enhance the performance of modified PWVD and modified LWD methods, the window length used in computation should be property selected according to the signal. These adaptive algorithms have better performace for nonstationary signal containated by noise. Furthermore, we introduced a technique to adaptively optimize the cone kernel distribution (CKD) for STFT by adjusting the cone length in response to changing signal. The resulting adaptive STFT shares many desirable properties with adaptive CKD and STFT. Finally, the LabVIEW language is also used to implement the derived adaptive algorithm, and some experiments for nonstationary signals analysis using the adaptive algorithm are conducted. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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