Feedforward active noise reduction for aircraft headsets
Thesis (MScEng)--University of Stellenbosch, 2003. === ENGLISH ABSTRACT: Active noise reduction (ANR) is a method of cancelling acoustic noise in a defined enclosure. Two methods exist to implement ANR, they are the analog feedback method and the digital feedforward method. Commercial ANR systems...
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ndltd-netd.ac.za-oai-union.ndltd.org-sun-oai-scholar.sun.ac.za-10019.1-497612016-01-29T04:02:59Z Feedforward active noise reduction for aircraft headsets Smith, Corne J. Lourens, J. G. Stellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering. Noise control Electronic circuits -- Noise Dissertations -- Electronic engineering Theses -- Electronic engineering Thesis (MScEng)--University of Stellenbosch, 2003. ENGLISH ABSTRACT: Active noise reduction (ANR) is a method of cancelling acoustic noise in a defined enclosure. Two methods exist to implement ANR, they are the analog feedback method and the digital feedforward method. Commercial ANR systems employing feedback methods have been around since the 1980's. Feedforward methods have however only become practically implemental with the age of fast real time digital signal processing. In current systems, feedback ANR is used to attenuate broadband noise whilst feedforward methods are used to attenuate narrow band or tonal noise [2]. This thesis investigates feedforward ANR to cancel broadband acoustic noise in aircraft headsets. Different adaptive filters, optimal configuration of adaptive filters and practical limitations to broadband attenuation for headsets are addressed. Results from this thesis show that at least 10dS noise energy attenuation is attainable over a bandwidth of 2.5kHz. A number of areas for further research are also identified. AFRIKAANSE OPSOMMING: Aktiewe geraas beheer (AGS) is 'n metode om akoestiese geraas te kanselleer in 'n gedefinieerde omgewing. Twee metodes bestaan om AGS te implementeer. Hulle is die analoog terugvoer en digitale vorentoevoer metode. Kommersiële AGS wat die terugvoer metode gebruik is al in gebruik van die 1980's. Vorentoevoer metodes is egter eers sedert vinnige intydse digitale sein prosessering moontlik. In huidige stelsels word terugvoer AGS gebruik vir die attenuasie van wyeband geraas terwyl vorentoevoer metodes gebruik word om nouband of enkel toon geraas te kanselleer [2]. Die tesis ondersoek vorentoevoer AGS om wyeband akoestiese geraas te kanselleer in vliegtuig kopstukke. Verskillende aanpasbare filters, optimale opstelling van aanpasbare filters en praktiese beperkings tot wyeband attenuasie vir kopstukke word ondersoek. Resultate van die tesis wys dat ten minste 10dS geraas energie attenuasie behaal kan word oor 'n bandwydte van 2.5kHz. 'n Aantal areas vir verder navorsing is ook geïdentifiseer. 2012-08-27T11:33:05Z 2012-08-27T11:33:05Z 2003-12 Thesis http://hdl.handle.net/10019.1/49761 en_ZA Stellenbosch University 1 v. (various foliations) : ill. Stellenbosch : Stellenbosch University |
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Noise control Electronic circuits -- Noise Dissertations -- Electronic engineering Theses -- Electronic engineering |
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Noise control Electronic circuits -- Noise Dissertations -- Electronic engineering Theses -- Electronic engineering Smith, Corne J. Feedforward active noise reduction for aircraft headsets |
description |
Thesis (MScEng)--University of Stellenbosch, 2003. === ENGLISH ABSTRACT: Active noise reduction (ANR) is a method of cancelling acoustic noise in a defined enclosure.
Two methods exist to implement ANR, they are the analog feedback method and the digital
feedforward method. Commercial ANR systems employing feedback methods have been around
since the 1980's. Feedforward methods have however only become practically implemental with
the age of fast real time digital signal processing. In current systems, feedback ANR is used to
attenuate broadband noise whilst feedforward methods are used to attenuate narrow band or
tonal noise [2].
This thesis investigates feedforward ANR to cancel broadband acoustic noise in aircraft
headsets. Different adaptive filters, optimal configuration of adaptive filters and practical
limitations to broadband attenuation for headsets are addressed.
Results from this thesis show that at least 10dS noise energy attenuation is attainable over a
bandwidth of 2.5kHz. A number of areas for further research are also identified. === AFRIKAANSE OPSOMMING: Aktiewe geraas beheer (AGS) is 'n metode om akoestiese geraas te kanselleer in 'n
gedefinieerde omgewing. Twee metodes bestaan om AGS te implementeer. Hulle is die
analoog terugvoer en digitale vorentoevoer metode. Kommersiële AGS wat die terugvoer
metode gebruik is al in gebruik van die 1980's. Vorentoevoer metodes is egter eers sedert
vinnige intydse digitale sein prosessering moontlik. In huidige stelsels word terugvoer AGS
gebruik vir die attenuasie van wyeband geraas terwyl vorentoevoer metodes gebruik word om
nouband of enkel toon geraas te kanselleer [2].
Die tesis ondersoek vorentoevoer AGS om wyeband akoestiese geraas te kanselleer in vliegtuig
kopstukke. Verskillende aanpasbare filters, optimale opstelling van aanpasbare filters en
praktiese beperkings tot wyeband attenuasie vir kopstukke word ondersoek.
Resultate van die tesis wys dat ten minste 10dS geraas energie attenuasie behaal kan word oor
'n bandwydte van 2.5kHz. 'n Aantal areas vir verder navorsing is ook geïdentifiseer. |
author2 |
Lourens, J. G. |
author_facet |
Lourens, J. G. Smith, Corne J. |
author |
Smith, Corne J. |
author_sort |
Smith, Corne J. |
title |
Feedforward active noise reduction for aircraft headsets |
title_short |
Feedforward active noise reduction for aircraft headsets |
title_full |
Feedforward active noise reduction for aircraft headsets |
title_fullStr |
Feedforward active noise reduction for aircraft headsets |
title_full_unstemmed |
Feedforward active noise reduction for aircraft headsets |
title_sort |
feedforward active noise reduction for aircraft headsets |
publisher |
Stellenbosch : Stellenbosch University |
publishDate |
2012 |
url |
http://hdl.handle.net/10019.1/49761 |
work_keys_str_mv |
AT smithcornej feedforwardactivenoisereductionforaircraftheadsets |
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