Results 261 to 270 of about 44,631 (307)
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Broadband noise in blue bronze K0.3MoO3
Physica B+C, 1986Abstract Low-frequency broadband noise was measured in the frequency range between 10−3 Hz and 1 MHz in K0.3MoO3. It was found that the measured noise spectrum cannot be represented only by a simple power law, and it is rather rugged. From this result, the energy and its distribution associated with the transition among the metastable states of the ...
A. MAEDA +3 more
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Sharpness and amplitude envelopes of broadband noise
The Journal of the Acoustical Society of America, 1990This paper discusses how amplitude envelope shapes, sound-pressure level, and duration of broadband noise affect sharpness and brightness. In the first experiment, sharpness, brightness, and similarity were judged for paired stimuli by 13 subjects. The stimuli consisted of broadband noise with different types of amplitude envelopes, sound-pressure ...
K, Ueda, M, Akagi
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Active Control of Broadband Noise
2006 IEEE International Conference on Systems, Man and Cybernetics, 2006This paper investigates the performance of active control for broadband disturbance using maximum pressure minimization. The theory and simulations of active control using single-channel, two-channel and three-channel systems are presented. Constrained minimisation of the pressure is introduced, to achieve control over the pressure in both frequency ...
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Variable-duration notched-noise experiments in a broadband-noise context
The Journal of the Acoustical Society of America, 1998To model the confusion of short-duration speech signals in noisy environments, it is important to characterize how humans resolve the spectral components of short-duration signals in background noise. Toward that end, a variable-duration notched-noise experiment was conducted in a noise context.
J J, Hant, B P, Strope, A A, Alwan
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Calibrating Broadband Highly Mismatched Noise Sources
IEEE Transactions on Instrumentation and Measurement, 2011Two methods are presented for calibrating broadband highly mismatched noise sources. The first is a reformulation and an extension of the procedure used for very accurately calibrating matched noise sources. It uses isolators and works whatever the source reflection factor.
Meys, René, Boukerroum, Fayçal
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Broadband noise in orthorhombic TaS3
Molecular Crystals and Liquid Crystals, 1985We report experimental results on the broadband noise in sliding charge density wave conductor orthorhombic TaS3. We propose that the noise has its origin in the interaction of a deformable condensate with random impurities. The experimental results are in excellent agreement with a phenomenological model based on fluctuations in threshold field due to
O Nark. Rorbins +3 more
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Nonlinear feedback active noise control for broadband chaotic noise
Applied Soft Computing, 2014Feedback active noise control has been used for tonal noise only and it is impractical for broadband noise. In this paper, it has been proposed that the feedback ANC algorithm can be applied to a broadband noise if the noise characteristic is chaotic in nature. Chaotic noise is neither tonal nor random; it is broadband and nonlinearly predictable.
Suman Bala Behera +2 more
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Prediction of fan broadband noise
4th AIAA/CEAS Aeroacoustics Conference, 1998The objective of the present work is to develop a complete theory of fan broadband noise in UHBR engines. This paper focuses on dipole broadband noise sources, resulting from the interaction of turbulent inflows with the fan rotor. A modal expansion in a hard-walled duct is used to evaluate the sound power radiated from the sources, taking into account
Benoit d, Michel Roger, Jean Cailleau
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Open Rotor Broadband Interaction Noise
18th AIAA/CEAS Aeroacoustics Conference (33rd AIAA Aeroacoustics Conference), 2012A theoretical model is presented for calculating the broadband noise produced by the interaction of an open rotor with the wake from either an upstream contra-rotating rotor or a stationary pylon. The model is used to investigate the dependence of the radiated noise on parameters such as pylon–rotor gap and the polar and azimuthal directivity of the ...
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Broadband noise modulation of multirotor aircraft
The Journal of the Acoustical Society of AmericaRotor broadband noise is typically analyzed over time scales encompassing multiple rotor periods. However, modulation of broadband noise levels with the blade passage frequency has been shown to be significant for human perception of wind turbine and helicopter noise. In contrast, broadband noise modulation has not been extensively studied for aircraft
Ze Feng (Ted) Gan +3 more
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