Topic
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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Papers
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TL;DR: In this article, two loudspeakers are driven by signals derived from a reference signal x(n) by adaptive filtering carried out by a programmed microprocessor and memory unit, which adapts the filtering in dependence on error signals el(n), from four microphones (421, 422, 423 and 424) distributed in the passenger compartment.
Abstract: To reduce noise inside a motor car passenger compartment, two loudspeakers (371, 372) are driven by signals derived from a reference signal x(n) by adaptive filtering carried out by a programmed microprocessor and memory unit (36) which adapts the filtering in dependence on error signals el(n) from four microphones (421, 422, 423 and 424) distributed in the passenger compartment. Reference filtering coefficients are initially determined by analysis of finite impulse responses when white noise is acoustically coupled from the loudspeakers (37) to the microphones (42), a white noise generator (48) being coupled to the unit (36). The reference signal x(n) is restricted to one or more selected harmonics or subharmonics of the fundamental noise frequency by a filter (34) which tracks the selected frequency. The selected frequency may be obtained from a coil (31) in the ignition circuit of the vehicle.
174 citations
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TL;DR: A new architecture is proposed that encodes a primary image to white noise based on iterative fractional Fourier transform that can provide additional keys for encryption to make the code more difficult to break.
174 citations
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TL;DR: This work manipulates the Hubbard-Stratonovich transformation to establish a novel theoretical methodology by which the reduced density matrix is formulated as an ensemble average of its random realizations in the auxiliary white noise fields.
Abstract: Based on the Hubbard–Stratonovich transformation, the dissipative interaction between the system of interest and the heat bath is decoupled and the separated system and bath thus evolve in common classical random fields. This manipulation allows us to establish a novel theoretical methodology by which the reduced density matrix is formulated as an ensemble average of its random realizations in the auxiliary white noise fields. Within the stochastic description, the interaction between the system and the bath is reflected in the mutually induced mean fields. The relationship between the bath-induced field and the influence functional in the path integral framework is revealed. As a demonstration of this approach, we derive the exact master equations for two model systems.
174 citations
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TL;DR: A novel velocity estimator based on the spectral moments of the in-phase and the quadrature phase components or the envelope of the received signal is provided, which proves the mean-square consistency of the covariance-based velocity estimators under some assumptions on the angle of arrival distribution.
Abstract: The estimation of the maximum Doppler spread or, equivalently, the vehicle velocity, is useful in improving handoff algorithms and necessary for the optimal tuning of parameters for systems that adapt to changing channel conditions. We provide a novel velocity estimator based on the spectral moments of the in-phase and the quadrature phase components or the envelope of the received signal. We characterize the joint effects of the Ricean K factor, the directivity and the angle of nonisotropic scattering, and the effects of additive white noise on our estimator and other covariance-based velocity estimators analytically. We also prove the mean-square consistency of the covariance-based velocity estimators under some assumptions on the angle of arrival distribution. Simulations illustrate our approach and compare with existing techniques.
171 citations
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TL;DR: It is found that the degree of correlation of the noise can cause tumor cell extinction.
Abstract: The logistic differential equation is used to analyze cancer cell population, in the presence of a correlated Gaussian white noise. We study the steady state properties of tumor cell growth and discuss the effects of the correlated noise. It is found that the degree of correlation of the noise can cause tumor cell extinction.
171 citations