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White noise
About: White noise is a research topic. Over the lifetime, 16496 publications have been published within this topic receiving 318633 citations.
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TL;DR: Adaptive Bayesian multiuser detectors based on the Gibbs sampler are derived and can incorporate the a priori symbol probabilities, and they produce as output the a posteriori symbol probability probabilities.
Abstract: We consider the problem of simultaneous parameter estimation and data restoration in a synchronous CDMA system in the presence of either additive Gaussian or additive impulsive white noise with unknown parameters. The impulsive noise is modeled by a two-term Gaussian mixture distribution. Bayesian inference of all unknown quantities is made from the superimposed and noisy received signals. The Gibbs sampler (a Markov chain Monte Carlo procedure) is employed to calculate the Bayesian estimates. The basic idea is to generate ergodic random samples from the joint posterior distribution of all unknown and then to average the appropriate samples to obtain the estimates of the unknown quantities. Adaptive Bayesian multiuser detectors based on the Gibbs sampler are derived for both the Gaussian noise synchronous CDMA channel and the impulsive noise synchronous CDMA channel. A salient feature of the proposed adaptive Bayesian multiuser detectors is that they can incorporate the a priori symbol probabilities, and they produce as output the a posteriori symbol probabilities. (That is, they are "soft-input soft-output" algorithms.) Hence, these methods are well suited for iterative processing in a coded system, which allows the adaptive Bayesian multiuser detector to refine its processing based on the information from the decoding stage, and vice versa-a receiver structure termed the adaptive turbo multiuser detector.
95 citations
TL;DR: In this paper, the authors investigate the sensitivity of VAR's to unit root processes and find that the inclusion of an artificially generated random walk has surprising effects on the system's variance decomposition and block exogeneity tests.
95 citations
TL;DR: In this article, the detection properties of scintillators used in charge-coupled device cameras suitable for electron microscopy are examined with particular emphasis on the statistics of electron scattering and photon generation in the scintilator.
95 citations
TL;DR: The scaling relations for the optimum noise and coupling strengths that correspond to the observed spatiotemporal stochastic resonance are derived via the f4 theory and shown to conform to the results of earlier numerical simulations in the large N limit.
Abstract: The synchronization and signal processing properties of a linearly coupled chain of N overdamped bistable elements, subject to a deterministic periodic signal and uncorrelated white noise, are addressed in the continuum limit of a f4 field theory. The scaling relations for the optimum noise and coupling strengths that correspond to the observed spatiotemporal stochastic resonance are derived via the f4 theory and shown to conform to the results of earlier numerical simulations in the large N limit.
95 citations
TL;DR: The main feature of the proposed method is that it uses the strength of glottal activity as against using the periodicity of the signal to distinguish voiced epochs from random instants detected in nonvoiced regions.
Abstract: In this paper, a new method for voiced/nonvoiced detection based on epoch extraction is proposed. Zero-frequency filtered speech signal is used to extract the instants of significant excitation (or epochs). The robustness of the method to extract epochs in the voiced regions, even with small amount of additive white noise, is used to distinguish voiced epochs from random instants detected in nonvoiced regions. The main feature of the proposed method is that it uses the strength of glottal activity as against using the periodicity of the signal. Performance of the proposed algorithm is studied on TIMIT and CMU ARCTIC databases, for two different noise types, white and vehicle noise from the NOISEX database, at different signal-to-noise ratios (SNRs). The proposed method performs similar or better than the popular normalized crosscorrelation based voiced/nonvoiced detection used in the open source utility wavesurfer, especially at lower SNRs.
95 citations