نتایج جستجو برای: noise propagation

تعداد نتایج: 296450  

2012
Xinyi Guo Fan Li Li Ma Geng Chen

This paper introduces a function of correlation between two hydrophones, basing on the Kuperman-Ingenito ocean ambient noise model. There is a similarity in form between the cross correlation function and the transfer function in ocean waveguide from a point source to a receiver. Thus, the noise cross correlation function between two hydrophones in vertical location can extract actual transfer ...

2005
Kent L. Gee Victor W. Sparrow

Because of the high noise levels radiated by military jet aircraft, it has been hypothesized that nonlinearity influences the propagation of the noise. A numerical model, which accounts for second-order cumulative nonlinearity, atmospheric absorption and dispersion, and geometrical spreading, has been developed to propagate jet noise waveforms. Numerical propagation of recorded waveforms from r...

2003
Shantanu Chakrabartty Gert Cauwenberghs

We propose margin propagation as an alternative to probability propagation in forward decoding. In contrast to sumproduct probability propagation, margin propagation only incurs addition and subtraction in the computation and thus leads to reduced complexity of implementation. Simulations indicate that margin based forward decoding is more robust to input noise and parameter mismatch than sumpr...

1998
E. Vilar

The concepts of propagation phase and fm noise are presented comparing oscillator noise with phase fluctuations introduced by the propagation medium. Numerical values of the spectral density and variance are presented. The experimental apparatus used to measure the noise using Italsat’s 40 GHz beacon is surveyed and experimental values of the excess spectral noise observed are presented. The ul...

Journal: :The Journal of the Acoustical Society of America 2010
Kent L Gee Anthony A Atchley Lauren E Falco Micah R Shepherd Lawrence S Ukeiley Bernard J Jansen John M Seiner

Bicoherence analysis has been used to characterize nonlinear effects in the propagation of noise from a model-scale, Mach-2.0, unheated jet. Nonlinear propagation effects are predominantly limited to regions near the peak directivity angle for this jet source and propagation range. The analysis also examines the practice of identifying nonlinear propagation by comparing spectra measured at two ...

2009
John A. Hildebrand

Ocean ambient noise results from both anthropogenic and natural sources. Different noise sources are dominant in each of 3 frequency bands: low (10 to 500 Hz), medium (500 Hz to 25 kHz) and high (>25 kHz). The low-frequency band is dominated by anthropogenic sources: primarily, commercial shipping and, secondarily, seismic exploration. Shipping and seismic sources contribute to ambient noise ac...

2016
Caleb Sieck Siu-Kit Lau

Noise propagation through open windows of finite depth into an enclosure" (2010). Architectural Engineering-Faculty Publications. 100.

Journal: :Physical review letters 1996
Blumenfeld

A minimal model is constructed for two-dimensional fracture propagation. The heterogeneous process zone is presumed to suppress stress relaxation rate, leading to non-quasistatic behavior. Using the Yoffe solution , I construct and solve a dynamical equation for the tip stress. I discuss a generic tip velocity response to local stress and find that noise-free propagation is either at steady sta...

Journal: :Physical review. E, Statistical, nonlinear, and soft matter physics 2002
J García-Ojalvo F Sagués J M Sancho L Schimansky-Geier

We show that external fluctuations induce excitable behavior in a bistable spatially extended system with activator-inhibitor dynamics of the FitzHugh-Nagumo type. This can be understood as a mechanism for sustained signal propagation in bistable media. The phase diagram of the stochastic system is analytically obtained and numerically verified. For small-noise intensities, front propagation be...

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