نتایج جستجو برای: frequency distribution function

تعداد نتایج: 2141696  

1998
Israel Cohen Shalom Raz

Utilizing the Shift-Invariant Wavelet Packet Decomposition (SIWPD), various useful properties relevant to time-frequency analysis, including high energy concentration and suppressed interference terms, can be achieved simultaneously in the Wigner domain. A prescribed signal is expanded on its best basis and transformed into the Wigner domain. Subsequently, the interference terms are eliminated ...

2003
Ahmad Zuri bin Sha'ameri

Digital modulation signals such as FSK are time-varying signals that can he represented in the time-frequency representation. The smooth lag-windowed Wigner-Ville distribution (SLWWVD) is proposed as a method to obtain accurate time-frequency representation of FSK signals used in HF (High Frequency) radio communications. Unlike existing time-frequency distributions such as the windowed Wigner-V...

This paper presents an optimal method of frequency load shedding (UFLS) based on the rate of change of frequency of load (ROCOFL) in islanded distribution networks (DN). The proposed method minimizes the average amount of penalties paid by the independent operator of the network by utilizing the relevant cost function. The function of islanded distribution network occurs after an error in the s...

Journal: :IEEE Trans. Information Theory 2001
Richard G. Baraniuk Patrick Flandrin Augustus J. E. M. Janssen Olivier J. J. Michel

The generalized entropies of Rényi inspire new measures for estimating signal information and complexity in the time–frequency plane. When applied to a time–frequency representation (TFR) from Cohen’s class or the affine class, the Rényi entropies conform closely to the notion of complexity that we use when visually inspecting time–frequency images. These measures possess several additional int...

2012
Yuhua Dong Yanqiu Cui

In this study, we proposed a joint time-frequency distribution of suppressing cross-terms aiming at cross-terms interference of Wigner-Ville distribution. According to the analyzed signal, the Wigner-Ville distribution and Smooth Pseudo Wigner-Ville distribution can be obtained. Moreover, the prototype of timefrequency distribution can be obtained by non-linear filter for Smooth Pseudo Wigner-V...

2012
Dragan KORAČ

A time-frequency distribution provides many advantages in the analysis of multicomponent nonstationary signals. The simultaneous signal representation with respect to the time and frequency axis defines the signal amplitude, frequency, bandwidth, and the number of components at each time moment. The Rényi entropy, applied to a time-frequency distribution, is shown to be a valuable indicator of ...

Journal: :IEEE Trans. Signal Processing 1993
Franz Hlawatsch Werner Kozek

We introduce a time-frequency representation of linear signal spaces which we call the Wigner distribution (WO) ofa linear signal space. Similar to the WD of a signal, the WD of a linear signal space describes the space’s energy distribution over the time-frequency plane. The WD of a signal space can be defined both in a deterministic and in a stochastic framework, and it can be expressed in a ...

2008
A. J. E. M. Janssen

This paper deals with the question how various lInaturalll conditions posed on time-frequency distribution functions prevent them to be non-negative everywhere for all signals. The attention is mainly restricted to distribution functions that involve the signal bilinearly. This paper summarizes and extends results recently obtained; the emphasis is on a coherent presentation of these results, r...

محمد حسین نادری, , محمود سلطان الکتابی, ,

  In this paper we present a detailed theoretical treatment of the 3-D temperature distribution induced by laser beam in photothermal displacement spectroscopy. We assume that a solid sample, which is deposited on a substrate and is in contact with a fluid, is irradiated by an intensity modulated cw laser source. By using a technique based on Greens function and integral transformations we find...

1997
Israel Cohen Shalom Raz David Malah

The Wigner distribution (WD) possesses a number of desirable mathematical properties relevant time-frequency analysis. However, the presence of interference terms renders the WD of multicomponent signals extremely di cult to interpret. In this work, we propose an adaptivedecomposition of the WD using extended libraries of orthonormal bases. A prescribed signal is expanded on a basis of adapted ...

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