Results 171 to 180 of about 9,260,103 (204)

Near-field acoustic holography of cyclostationary sound fields

The Journal of the Acoustical Society of America, 2012
The radiated sound field of rotating machinery or reciprocating machinery has a significant periodically time-variant nature. This is a kind of non-stationary sound field and called cyclostationary sound field. In the conventional planar near-field acoustic holography(PNAH), this kind of sound field is treated as stationary field, so the information ...
Zhimin Chen, Hongchun Chen, Haichao Zhu
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An application of the neural network in the near-field acoustic holography

International Technology and Innovation Conference 2006 (ITIC 2006), 2006
The near-field acoustic holography (NAH) is an effective and useful noise measurement method. There are many methods for reconstruction of the sound source, but the measurement circumstance is limited and the random noise is unavoidable. In this paper, a new holography reconstruction method based on neural network (NN) is proposed, which can identify ...
null Gao Yinhan, null Song Dan, null Liang lie, null Zhou Xiaohua   +3 more
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Wrapping a violin with planar near-field acoustic holography.

The Journal of the Acoustical Society of America, 1996
Planar near-field acoustic holography gives one the ability to reconstruct the sound pressure radiated from a source in a three-dimensional field from a single two-dimensional near-field measurement. Traditionally, only one measurement plane has been used which gives the sound radiation in a half-space. In this paper, the near-field acoustic holography
Lily M. Wang, Courtney B. Burroughs
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Progress of the Patch Near-Field Acoustical Holography Technique

Acta Acustica united with Acustica, 2008
The development of patch near-field acoustic holography (Patch-NAH) has been rapid in recent years. Compared to the traditional NAH techniques, the Patch-NAH method possesses the advantage of solving engineering problems, and is especially suitable for reconstructing partial sound fields and for obtaining other acoustic parameters.
Chao Yang, Jin Chen, Wei-Fei Xue, Jia-qing Li   +3 more
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Near-field acoustic holography measurements of the acoustic radiation from violins

The Journal of the Acoustical Society of America, 1996
As previously described, an open-frame mechanical bowing apparatus has been constructed to excite a violin [L. M. Wang and C. B. Burroughs, J. Acoust. Soc. Am. 99, 2502(A) (1996)]. An array of microphones is mounted to this apparatus on each of the six sides of the frame, boxing the violin source. Complex pressure measurements made in the near field of
Lily M. Wang, Courtney B. Burroughs
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Near-Field Acoustic Holography of Cyclostationary Sound Field

Advanced Materials Research, 2013
The radiated sound field of rotating machinery or reciprocating machinery has a significant periodically time-variant nature. This is a kind of non-stationary sound field and called cyclostationary sound field. In the conventional planar near-field acoustic holography(PNAH), this kind of sound field is treated as stationary field, so the information ...
openaire   +1 more source

Near-field acoustic holography for acoustic noise source identification in turbomachinery

2009 IEEE Sensors Applications Symposium, 2009
A novel approach using basis expansions of acoustic sources is proposed to better condition the inverse problem in NAH. Results indicate that the basis expansion representation of sources provides better source reconstruction results through effectively combating ill-posedness of the inverse problem.
Tariq Khan, Pradeep Ramuhalli, Ravi Raveendra, W. Zhang   +3 more
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Data extension near-field acoustic holography based on improved regularization method for resolution enhancement

, 2019
In recent years, patch near-field acoustic holography (NAH) has gradually emerged for the reconstruction of sound field radiated from large-scale sound source under the condition of small holographic aperture in engineering practice.
Laixu Jiang, You-Hong Xiao, Guangping Zou   +2 more
semanticscholar   +1 more source

Surface decomposition method for near-field acoustic holography.

The Journal of the Acoustical Society of America, 2011
Near-field acoustic holography reconstruction of the acoustic field at the surface of an arbitrarily shaped radiating structure from pressure measurements at a nearby conformal surface is obtained from the solution of a boundary integral equation. This integral equation is discretized using the equivalent source method to be transformed into a matrix ...
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Partial source discrimination in near field acoustic holography

Applied Acoustics, 1999
Abstract Decomposition techniques based on principal component analysis (PCA) and partial coherent output power (PCOP) analysis are applied to scanning near field acoustic holography (NAH) in order to identify partial sources. Where location of partial sources is uncertain, inaccessible, or the underlying physical process is not well understood ...
openaire   +1 more source