Topic
Discrete-time Fourier transform
About: Discrete-time Fourier transform is a research topic. Over the lifetime, 5072 publications have been published within this topic receiving 144643 citations. The topic is also known as: DTFT.
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Papers
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TL;DR: The sampling theorem for OLCT signals presented here serves as a unification and generalization of previously developed sampling theorems.
Abstract: The offset linear canonical transform (OLCT) is the name of a parameterized continuum of transforms which include, as particular cases, the most widely used linear transforms in engineering such as the Fourier transform (FT), fractional Fourier transform (FRFT), Fresnel transform (FRST), frequency modulation, time shifting, time scaling, chirping and others. Therefore the OLCT provides a unified framework for studying the behavior of many practical transforms and system responses. In this paper the sampling theorem for OLCT is considered. The sampling theorem for OLCT signals presented here serves as a unification and generalization of previously developed sampling theorems.
100 citations
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TL;DR: Fast Fourier analysis (FFA) and fast Fourier synthesis (FFS) algorithms are developed for computing the discrete Fourier transform of a real series, and for synthesizing a realseries from its complex Fourier coefficients.
Abstract: Fast Fourier analysis (FFA) and fast Fourier synthesis (FFS) algorithms are developed for computing the discrete Fourier transform of a real series, and for synthesizing a real series from its complex Fourier coefficients. A FORTRAN program implementing both algorithms is given in the Appendix.
99 citations
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TL;DR: This paper develops a 2D DFRFT which can preserve the rotation properties and provide similar results to continuous FRFT.
98 citations
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04 Dec 1990TL;DR: In this article, a 2D Fourier transform technique involving both spatial and time transformations is presented to identify and measure the amplitudes of individual Lamb wave modes, and the results obtained from both numerical and experimental investigations of Lamb waves propagating in steel plates are presented using an isometric projection.
Abstract: The key problem associated with the quantitative measurement of the characteristics of propagating Lamb waves is that more than one wave mode can exist at any given frequency. Therefore, a simple Fourier transformation from the time to the frequency domain cannot distinguish between the different modes. A 2-D Fourier transform technique involving both spatial and time transformations from which the required information can be obtained is presented. The results obtained from both numerical and experimental investigations of Lamb waves propagating in steel plates are presented using an isometric projection, which gives a 3-D view of the wave-number dispersion curves. The results show the effectiveness of using the 2-D Fourier transform method to identify and measure the amplitudes of individual Lamb modes. >
98 citations