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The synchrosqueezing transform, a kind of reassignment method, aims to sharpen the time-frequency representation and to separate the components of a multicomponent non-stationary signal. In this paper, we consider the short-time Fourier…

Signal Processing · Electrical Eng. & Systems 2019-09-27 Lin Li , Haiyan Cai , Hongxia Han , Qingtang Jiang , Hongbing Ji

The Special Affine Fourier Transformation(SAFT), which generalizes several well-known unitary transformations, has been demonstrated as a valuable tool in signal processing and optics. In this paper, we explore the multivariate dynamical…

Functional Analysis · Mathematics 2024-09-16 Meng Ning , Li-Ping Wu , Qing-yue Zhang , Bei Liu

The directional state transition tensor (DSTT) reduces the complexity of state transition tensor (STT) by aligning the STT terms in sensitive directions only, which provides comparable accuracy in orbital uncertainty propagation. The DSTT…

Instrumentation and Methods for Astrophysics · Physics 2024-12-11 Xingyu Zhou , Roberto Armellin , Dong Qiao , Xiangyu Li

We study the phase retrieval problem for the short-time Fourier transform on the groups $\mathbb{Z}$, $\mathbb{Z}_d$ and $\mathbb{R}^d$. As is well-known, phase retrieval is possible, once the window's ambiguity function vanishes nowhere.…

Functional Analysis · Mathematics 2022-06-15 David Bartusel

The covariance function and the variogram play very important roles in modelling and in prediction of spatial and spatio-temporal data. The assumption of second order stationarity, in space and time, is often made in the analysis of spatial…

Statistics Theory · Mathematics 2016-10-20 T. Subba Rao , Gy. Terdik

We unify the discrete Fourier transform (DFT), discrete cosine transform (DCT), Walsh-Hadamard, Haar wavelet, Karhunen-Lo\`eve transform, and several others along with their continuous counterparts (Fourier transform, Fourier series,…

Signal Processing · Electrical Eng. & Systems 2026-05-19 Mitchell A. Thornton

In many processes, the variations in underlying characteristics can be approximated by noisy multi-periodic patterns. If large-scale patterns are superimposed by a noise with long-range correlations, the detection of multi-periodic patterns…

Quantitative Methods · Quantitative Biology 2019-12-09 V. R. Chechetkin , V. V. Lobzin

The one-dimensional (1D) fractional Fourier transform (FRFT) generalizes the Fourier transform, offering significant advantages in the time-frequency analysis of non-stationary signals. While various 2D extensions exist, such as the 2D…

Signal Processing · Electrical Eng. & Systems 2026-03-03 Daxiang Li , Zhichao Zhang , Wei Yao

We propose a bootstrapping framework to quantify uncertainty in time-frequency representations (TFRs) generated by the short-time Fourier transform (STFT) and the STFT-based synchrosqueezing transform (SST) for oscillatory signals with…

Methodology · Statistics 2026-01-28 Hau-Tieng Wu , Zhou Zhou

Let $\operatorname{St}^{n}_{k}\subset\mathbb{R}^{n\times k}$ be the set of all $n\times k$ matrices whose columns are mutually orthogonal and of unit Euclidean length, and let $\mu_{n,k}$ be the surface measure corresponding to this…

Classical Analysis and ODEs · Mathematics 2021-11-18 Nikolaos Chatzikonstantinou

The Discrete Fourier Transform (DFT) is widely utilized for signal analysis but is plagued by spectral leakage, leading to inaccuracies in signal approximation. Window functions play a crucial role in mitigating spectral leakage by…

Signal Processing · Electrical Eng. & Systems 2023-12-27 Haichao Xu , Xingpao Suo

We study the short-time Fourier transform on the space $\mathcal{K}_{1}'(\mathbb{R}^n)$ of distributions of exponential type. We give characterizations of $\mathcal{K}_{1}'(\mathbb{R}^n)$ and some of its subspaces in terms of modulation…

Functional Analysis · Mathematics 2017-01-11 Sanja Kostadinova , Stevan Pilipovic , Katerina Saneva , Jasson Vindas

Classical dynamical density functional theory (DDFT) is one of the cornerstones of modern statistical mechanics. It is an extension of the highly successful method of classical density functional theory (DFT) to nonequilibrium systems.…

Soft Condensed Matter · Physics 2020-12-29 Michael te Vrugt , Hartmut Löwen , Raphael Wittkowski

We study the real-time dynamics retrieval from a time series via the time-frequency (TF) analysis with the minimal latency guarantee. While different from the well-known intrinsic latency definition in the filter design, a rigorous…

Multimedia · Computer Science 2016-06-30 Li Su , Hau-tieng Wu

The Short-Time Fourier Transform (STFT) has been a staple of signal processing, often being the first step for many audio tasks. A very familiar process when using the STFT is the search for the best STFT parameters, as they often have…

Audio and Speech Processing · Electrical Eng. & Systems 2021-05-17 An Zhao , Krishna Subramani , Paris Smaragdis

Background: Windowed Fourier decompositions (WFD) are widely used in measuring stationary and non-stationary spectral phenomena and in describing pairwise relationships among multiple signals. Although a variety of WFDs see frequent…

Quantitative Methods · Quantitative Biology 2019-01-30 Christopher K. Kovach , Phillip E. Gander

Odd diffusion breaks time-reversal symmetry in overdamped systems through transverse probability currents while preserving equilibrium steady states. In this work, we develop a dynamical density functional theory (DDFT) for dense…

Soft Condensed Matter · Physics 2026-02-02 Iman Abdoli , René Wittmann , Hartmut Löwen

The Fractional Fourier Transform (FRT) corresponds to an arbitrary-angle rotation in the phase space, e.g. the time-frequency (TF) space, and generalizes the fundamentally important Fourier Transform. FRT applications range from classical…

Optics · Physics 2024-03-06 Michał Lipka , Michał Parniak

In recent years directional multiscale transformations like the curvelet- or shearlet transformation have gained considerable attention. The reason for this is that these transforms are - unlike more traditional transforms like wavelets -…

Functional Analysis · Mathematics 2009-12-13 Philipp Grohs

An adaptive time-frequency representation (TFR) with higher energy concentration usually requires higher complexity. Recently, a low-complexity adaptive short-time Fourier transform (ASTFT) based on the chirp rate has been proposed. To…

Information Theory · Computer Science 2017-05-26 Soo-Chang Pei , Shih-Gu Huang