نتایج جستجو برای: wigner distribution

تعداد نتایج: 613030  

Journal: :IEEE Trans. Acoustics, Speech, and Signal Processing 1988
Boualem Boashash

We show that a correct use of the Wigner Distribution (WD) for time-frequency signal analysis requires use of the analytic signal. This version, often referred to as the Wigner-Ville Distribution (WVD), is straightforward to compute, does not exhibit any aliasing problem, and introduces no frequency artifacts. The problems introduced by the use of the Wigner Distribution with a real signal are ...

1997
Harald Oehlmann David Brie

The Local Wigner-Ville Distribution (LWVD) extends the Cohen's class time-frequency distributions (TFD) by the de nition of a kernel for each time-frequency point(local kernel). The subject of the paper is the determination of these local kernels for interference reduction. Starting from the simple idea of the local limitation of the Wigner-Ville TFD integral bounds, a method is presented to es...

2000
Martin J. Bastiaans Tatiana Alieva

The Wigner distribution of rotationally symmetric partially coherent light is considered and the constraints for its moments are derived. While all odd– order moments vanish, these constraints lead to a drastic reduction in the number of parameters that we need to describe all even–order moments: whereas in general we have (N + 1)(N + 2)(N + 3)/6 different moments of order N , this number reduc...

2005
J. O’ Toole B. Boashash

An optimised time-frequency signal analysis software tool is presented here as a MATLAB toolbox. This toolbox is implemented using existing and novel methods for a specific class of Time-Frequency Distributions (TFDs) called quadratic TFDs. This is first applied to a TFD called the Wigner-Ville Distribution (WVD), as all other quadratic TFDs can be represented as a smoothed (in both time and fr...

2004
D. Dragoman

A phase space representation of the Aharonov-Bohm effect is presented. It shows that the shift of interference fringes is associated to the interference term of the Wigner distribution function of the total wavefunction, whereas the interference pattern is defined by the common projections of the Wigner distribution functions of the interfering beams. * Correspondence address: D. Dragoman, P.O....

2004
M.H.S. Amin A. N. Omelyanchouk

A technique for studying collisionless dynamics of a homogeneous superconducting system is developed which is based on Riccati parametrization of the Wigner distribution function. The quantum evolution of the superconducting order parameter, initially deviating from the equilibrium value, is calculated using this technique. The effect of a time-dependent BCS paring interaction on the dynamics o...

2003
Martin J. Bastiaans Tatiana Alieva

The Wigner distribution of rotationally symmetric partially coherent light is considered and the constraints for its moments are derived. While all odd-order moments vanish, these constraints lead to a drastic reduction in the number of parameters that we need to describe all evenorder moments. A way to measure the moments as intensity moments in the output planes of (generally anamorphic but s...

2003
Cohn JR Sheppard Kieran G Larkin

The connection between the Wigner function and the generalized OTF, and between the ambiguity function and the generalized OTF is investigated for non-paraxial scalar wavefields. The treatment is based on two-dimensional (2-D) wavefields for simplicity, but can be extended to the three-dimensional case.

Journal: :IEEE Trans. Signal Processing 1993
Boualem Boashash Peter O'Shea

This correspondence presents an iterative instantaneous frequency (IF) estimation scheme in which successive IF estimates are obtained from the peak of the cross Wigner-Ville distribution (XWVD) using a reference signal synthesized from an initial IF estimate. Theoretical and practical aspects of performance are discussed, and compared with other methods.

2008
M. Murakami G. W. Ford R. F. O ’ Connell

Much of the discussion of decoherence has been in terms of a particle moving in one dimension that is placed in an initial superposition state (a Schrödinger " cat " state) corresponding to two widely separated wave packets. Decoher-ence refers to the destruction of the interference term in the quantum probability function. Here, we stress that a quantitative measure of decoherence depends not ...

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