Time-frequency techniques for digital signal processing /
The demand for analysis of nonstationary signals has resulted in a subsequent increase in the use of time-frequency techniques. Traditional time-frequency techniques such as the short-time Fourier transform (STFT) and the Wigner-Ville distribution (WVD) have limitations, such as a fixed resolution...
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| Format: | Thesis Book |
| Language: | English |
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[Place of publication not identified] :
[publisher not identified] ;
1998.
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| Online Access: | http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=737703831&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | The demand for analysis of nonstationary signals has resulted in a subsequent increase in the use of time-frequency techniques. Traditional time-frequency techniques such as the short-time Fourier transform (STFT) and the Wigner-Ville distribution (WVD) have limitations, such as a fixed resolution and cross-term interference. The latest development in wavelets involves the study of time-scale distributions, which have the advantage of a varied time-frequency resolution. In such DSP applications as inverse synthetic aperture radar (ISAR) imaging, the conventional Fourier method results in a blurred image due to its inability to deal with the time- varying frequency. To obtain a clear image with a high resolution, we propose the use of wavelet-packet based cross-term deleted representation (WPCDR). When this representation is applied to the ISAR imaging, a much sharper image is obtained. In the detection of multiple linear frequency-modulated (LFM) signals, the Radonambiguity transform (RAT), which combines the ambiguity function and the Radon transform, is proposed. This method reduces the 2-D problem of the Radon-Wigner transform (RWT) based detection to a 1-D problem, and consequently reduces the computational load. Motivated by the need to develop a more efficient encoding method for magnetic resonance imaging (MRI), a dynamic wavelet encoding technique is proposed. With this technique, the region of interest (ROI) is determined and then updated by wavelet encoded imaging. Images can therefore be generated at a rate faster than standard phase encoded images, and with no sacrifice in resolution. |
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| Item Description: | Vita. "Major Subject: Electrical Engineering". |
| Physical Description: | xii, 98 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references: pages 90-97. |