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1
NAKAGAWA, Seiichi, Souta HAMAGUCHI e Norihide KITAOKA. "Noisy Speech Recognition Based on Integration/Selection of Multiple Noise Suppression Methods Using Noise GMMs". Institute of Electronics, Information and Communication Engineers, 2008. http://hdl.handle.net/2237/14965.
Testo completo
2
Gisel, Christoph. "Noise pod : the need for urban noise". Thesis, Konstfack, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:konstfack:diva-25.
Testo completoAbstract (sommario):
This project is about the thought that urban noise is more needed than we may think. A lot of people can be really disturbed and upset about a noisy environment surrounding them. I want to show with this noise pod, a space where you can sit/lay while listening to everyday urban noise compositions, that noise can be really relaxing and enjoyable. Relaxation does not only come from the right choice of noise at the right time it also depends on the environment that you enjoy the soundscape in. This pod - a small capsule of space - is a place to sit by yourself, choose a noise composition and listen to it reflectivity. Compleatly insulated from the surrounding noise world, you will be able to enjoy the noise wich is supported with an interactive light installation. Escape from the noise you are disturbed by, through listening to the noise you like.
3
Klein, Achim. "Annoyance indicators for various urban road vehicle pass-by noises and urban road traffic noise combined with tramway noise". Thesis, Vaulx-en-Velin, Ecole nationale des travaux publics, 2015. http://www.theses.fr/2015ENTP0002/document.
Testo completoAbstract (sommario):
La pollution sonore est un problème majeur pour les résidents des zones urbaines. La directive Européenne 2002/49/CE impose aux états membres l’établissement de cartes de bruit. Ces dernières sont construites sur la base de l’indice énergétique Lden, également utilisé dans les relations dose-effet établies pour prédire la gêne. Toutefois, pour l’évaluation de la gêne due au bruit dans les zones urbaines, la pertinence de cet indice est souvent remise en question. En effet, de nombreuses études ont montré que les caractéristiques temporelles et spectrales des bruits environnementaux influencent aussi les réponses de gêne et ne sont pas prises en compte dans cet indice. Cette thèse vise à contribuer à l’amélioration de la caractérisation de la gêne due au bruit des véhicules routiers en ville. Elle est basée sur des expériences réalisées en laboratoire. Elle comprend deux parties principales. La première partie a comme objectif de progresser sur la caractérisation physique et perceptive du bruit des passages de divers véhicules routiers en milieu urbain tels que les bus, les deux-roues motorisés, les poids lourds et les véhicules légers. Une attention particulière a été portée sur la caractérisation de la gêne due aux deuxroues motorisés qui sont cités parmi les véhicules routiers les plus gênants et sont peu étudiés dans la littérature. Dans cette perspective, un indicateur acoustique caractéristique de la gêne due au bruit routier urbain a été déterminé : il rend compte de différents attributs auditifs gênants en associant la sonie, un indice spectral et deux indices de modulation proposés dans le cadre de ces travaux. Dans les zones urbaines, les riverains sont souvent exposés à la circulation routière en présence d’autres sources de bruit de l’environnement. L’objectif principal de la deuxième partie est la prédiction de la gêne totale due au bruit du trafic routier urbain combiné avec le bruit de tramway. Dans le but de caractériser la gêne totale, les phénomènes perceptifs liés à la combinaison de ces bruits sont tout d’abord étudiés. Ensuite, l’indicateur proposé précédemment pour caractériser la gêne due au bruit des passages de différents véhicules routiers est testé lorsque différents trafics routiers urbains sont considérés. Sur la base de ces résultats, des modèles permettant de caractériser la gêne due au bruit de trafic routier urbain combiné au bruit de tramway ont été proposésNoise pollution is a major concern for residents of urban areas. To date, the European directive 2002/49/CE requires member states to represent community noise through noise maps. These are produced using the Lden (day-evening-night level) index which is also employed for dose-effect relationships in noise annoyance prediction. However, for the assessment of noise annoyance in urban areas, its relevance is often questioned. Numerous studies have shown that noise annoyance due to community noise is not solely based on the sound pressure level and other acoustical signal characteristics such as temporal and spectral features influence noise annoyance ratings. This thesis aims to improve the assessment of noise annoyance due to various road vehicle noises in cities. It is based on experiments carried out in laboratory conditions and comprises two main parts. The first addresses the enhancement of the physical and perceptual characterization of annoyance due to various urban road vehicle pass-by noises, such as buses, poweredtwo- wheelers, heavy vehicles and light vehicles. A specific focus is put on the characterization of annoyance due to powered-two-wheelers which are among the most annoying road vehicles and studied little in the existing literature. An indicator accounting for annoyance-relevant auditory attributes of urban road vehicle pass-by noises is determined: it comprises loudness, a spectral index and two modulation indices proposed in this work. In urban agglomerations, people are often exposed to road traffic in presence of a variety of other environmental noise sources. The focal point of the second part is on the prediction of total annoyance due to urban road traffic noise combined with tramway noise. In the aim of adequately characterizing total annoyance, first the perceptual phenomena involved in annoyance due to the combination of the sources are studied. Furthermore, the analysis allows for the testing of the proposed noise annoyance indicator for the characterization of urban road traffic noise. To characterize annoyance due to tramway noise, an indicator determined in a recent study is employed. Based on these indicators and the findings regarding perceptual phenomena, models for the prediction of total annoyance due to combined urban road traffic and tramway noise are proposed
4
Kaymak, Erkan. "Noise reduction and active noise control of high frequency narrow band dental drill noise". Thesis, Brunel University, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.445923.
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5
Reschikoff, S. E. "Advanced Noise Generator Method of Flicker Noise Measurement". Thesis, Sumy State University, 2015. http://essuir.sumdu.edu.ua/handle/123456789/40983.
Testo completoAbstract (sommario):
Noise of electronic devices can be measured by comparison using a noise source at input and an output noise meter. It is noise generator method. It can be used to easily obtaining equivalent input noise of semiconductor devices. But this method is usually recommended for higher frequencies, because measurement generator must give white noise. Besides this, we obtain only noise level at broad band.
6
Cochachin, Henostroza Franklin Rafael. "Noise-against-Noise Decoders : Low Precision Iterative Decoders". Thesis, Lorient, 2019. http://www.theses.fr/2019LORIS527.
Testo completoAbstract (sommario):
Dans cette thèse, deux décodeurs améliorés sont définis en utilisant un canal d’entrée quantifié avec seulement 3 ou 4 bits de précision pour les codes low-density parity-check (LDPC). Un algorithme de post-traitement pour les décodeurs itératifs de faible précision est également proposé. L'un des décodeurs proposés, appelé décodeur Noise-Against-Noise Min-Sum (NAN- MS), intègre une certaine quantité de perturbations aléatoires dues à une injection délibérée de bruit. L'autre des décodeurs proposés, appelé décodeur Sign-Preserving Min-Sum (SP-MS), conserve toujours le signe des messages et utilise toutes les combinaisons possibles pouvant être générées pour une précision donnée. De plus, le décodeur SP-MS peut réduire la précision de ses messages d'un bit tout en maintenant les mêmes performances de correction d'erreur. Le décodeur NAN-MS et le décodeur SP-MS présentent un gain de SNR pouvant atteindre 0,43 dB dans la région du waterfall de la courbe de performances. D'autre part, l'algorithme de post- processing proposé est très efficace et facilement adaptable aux décodeurs de faible précision. Pour le code IEEE ETHERNET, l'algorithme de post-processing implémenté dans un décodeur SP- MS de très faible précision permet de réduire le niveau d'erreur au-dessous d'un FER de 10-10. Sur un ASIC en technologie 28nm, une architecture entièrement parallèle du décodeur peut être mis en place sur une surface de 1.76 mm2, avec un débit de décodage de 319.34 Gbit/s et une efficacité matérielle de 181.44 Gbit/s/mm2In this thesis, two improved decoders are defined using quantized input channel with only 3 or 4 bits of precision for low-density parity-check (LDPC) codes. Also, a post-processing algorithm for low precision iterative decoders is proposed. One of the proposed decoders, named Noise- Against-Noise Min-Sum (NAN-MS) decoder, incorporates a certain amount of random perturbation due to deliberate noise injection. The other of the proposed decoders, named Sign- Preserving Min-Sum (SP-MS) decoder, always preserve the sign of the messages and it uses all the possible combinations that can be generated for a given precision. Also, the SP-MS decoder can reduce the precision of its messages by one bit maintaining the same error correcting performance. The NAN-MS decoder and the SP-MS decoder present a SNR gain up to 0.43 dB the waterfall region of the performance curve. On the other hand, the proposed post-processing algorithm is very efficient and easily adaptable in low precision decoders. For the IEEE ETHERNET code, the post-processing algorithm implemented in a very low precision SP-MS decoder helps to lower the error floor below a FER of 10-10. On an ASIC of 28 nm of technology, the implementation results of a fully parallel architecture produces an area consumed by the decoder of 1.76 mm2, a decoding throughput of 319.34 Gbit/s, and a hardware efficiency of 181.44 Gbit/s/mm2
7
Johnston, Adam Michael. "Noise Exposure System for Noise-Induced Hearing Loss". OpenSIUC, 2012. https://opensiuc.lib.siu.edu/theses/794.
Testo completoAbstract (sommario):
There is an estimated 10 million Americans that suffer from permanent, irreversible hearing loss from their workplace. Many soldiers come back from battle with this damage, mainly from the high sound levels of their weapons that they are exposed to. The U.S. government spends over $250 million a year in compensation to those whose hearing has been damaged. There are current medicines that have proven to help eliminate or lessen the affects from certain types of noise induced hearing loss, specifically from prolonged expose. A noise exposure system was needed to be built for impulse noise induced hearing loss testing. That would help lead to a medicine for impulse noise induced hearing loss. A system was designed and built to replicate the noise signal of an M-16 rifle. The system's digital noise signal produced was comparable to the recorded M-16 noise signal, which reached a 145 dB level. Testing showed that the relationship between the amplitude and the maximum levels measured were linear. Sound levels of the produced impulse waves had a maximum limit of approximately 160 dB. The system was designed with the idea of customization. There are multiple parameters that can be adjusted to best fit the testing needs. The noise exposure system will be used by researchers in the SIU school of medicine in research designed to test the effect. The results from Dr. the research will validate the effectiveness of the noise exposure system that was built.
8
Gualandi, Nicola <1978>. "Aircraft noise performance evaluation and airport noise management". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2009. http://amsdottorato.unibo.it/1356/1/Gualandi_Nicola_Aircraft_noise_performance_evaluation_and_airport_noise_management.pdf.
Testo completo
9
Gualandi, Nicola <1978>. "Aircraft noise performance evaluation and airport noise management". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2009. http://amsdottorato.unibo.it/1356/.
Testo completo
10
Robert, Rene Jean. "Measuring noise level reduction using an artificial noise source". Thesis, Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/54480.
Testo completoAbstract (sommario):
Buildings located near airports may be subjected to significant noise levels due to aircraft flyovers. Aircraft noise is particularly annoying when compared to other traffic noises due to its intermittent nature. While noise control is typically performed at the source, sound insulation programs are in place to improve the acoustic performance of a residence affected by the flyovers. Noise Level Reduction (NLR) is a common metric used in the United States to determine whether a residence qualifies for such programs. Sound insulation programs are available to houses that have an indoor Day Night Average Sound Level (DNL) greater than 45 dBA. NLR is a single-number metric used to quantify the ability for a building or building element to reduce the transmission of external sound pressure levels generated by aircraft. In addition to determining whether a residence qualifies, NLR can be used to quantify the effectiveness of the modifications performed as a result of the sound insulation program. NLR measurements with a loudspeaker offer an alternative method to those performed with aircraft flyovers, offering flexibility to the consultants that perform these measurements in the field. The purpose of this research was to better understand and improve the loudspeaker test for measuring NLR, providing a resource to the aircraft noise industry. Testing was completed on a "test house" that was constructed on campus with construction methods typical of a mixed-humid climate. The angular dependency, repeatability, and reproducibility of NLR, among other factors, were evaluated with field measurements. Significant NLR variations were observed with changes in lateral and vertical angles of incidence.
11
Jackson, Victoria Jane. "Decisive noise : noisy intercellular signalling analysed and enforced through synthetic biology". Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/decisive-noise-noisy-intercellular-signalling-analysed-and-enforced-through-synthetic-biology(ccda209b-99da-4b61-bbd2-a9bb1a650b91).html.
Testo completoAbstract (sommario):
Individual cells in a genetically identical population, exposed to the same environment, can show great variation in their protein expression levels. This is due to noise, which is inherent in many biological processes, due in part to the low molecule numbers and probabilistic interactions which lead to stochasticity. Much of the work in the field of noise and its propagation in gene expression networks, whether it is experimental, modelling or theoretical, has been conducted on networks/systems that occur within a single cell. However, cells do not exist solely in isolation and understanding how cells are able to coordinate their behaviour despite this noise is an interesting area of expansion for the field. In this study, a synthetic intercellular communication system was designed that allows the investigation of how noise is propagated in intercellular communication. The communication system consists of separate sender and receiver cells incorporating components of the Lux quorum sensing system of Vibrio fischeri. The sender cell was designed so that the production of the signalling molecule, 3-oxohexanoyl homoserine lactone, is able to be controlled by addition of isopropyl-β-D-thio-galactoside (IPTG) and monitored via a reporter gene. The receiver cell was designed with a dual reporter system to enable the response of the cell to the signalling molecule to be monitored and the intrinsic and extrinsic noise contributions to the total noise to be calculated. Sender and the receiver cells were engineered in Escherichia coli. The functionality of the receiver cells was tested in the presence of known concentrations of the signalling molecule. The population response and the noise characteristics of the receiver cells in the homogeneous environment were determined from single cell measurements. The functionality of the sender cells was tested in the presence of a range of IPTG concentrations and the induction of expression from the LacI-repressible promoter was monitored. Mathematical models of the system were developed. Stochastic simulations of the models were used to investigate any unexplained behaviour seen in the characterisation of the cells. The full functionality of the intercellular communication system was then tested by growing the receiver in the collected media of the induced sender cells. The response of the receiver cells to the signalling molecule in the media was again characterised using single cell measurements of the reporter expression levels. The analysis of mixed populations of the sender and receiver cells was hampered by the technical limitations of the instruments used for the single cell measurements. Difficulties were encountered in simultaneous and specific measurement of the three reporter genes. Two methods for overcoming this issue were proposed using microscopy, and one of these methods was shown to have potential in overcoming the issue.
12
Gattoni, Sara. "Noisy Oncology: applications of bounded noise transitions in modelling tumor growth". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2011. http://amslaurea.unibo.it/2650/.
Testo completoAbstract (sommario):
I tumori macroscopici e microscopici, dopo la loro prima fase di crescita, sono composti da un numero medio elevato di cellule. Così, in assenza di perturbazioni esterne, la loro crescita e i punti di equilibrio possono essere descritti da equazioni differenziali. Tuttavia, il tumore interagisce fortemente col macroambiente che lo circonda e di conseguenza una descrizione del tutto deterministica risulta a volte inappropriata. In questo caso si può considerare l'interazione con fluttuazioni statistiche, causate da disturbi esterni, utilizzando le equazioni differenziali stocastiche (SDE). Questo è vero in modo particolare quando si cerca di modellizzare tumori altamente immunogenici che interagiscono con il sistema immunitario, in quanto la complessità di questa interazione risulta in fenomeni di multistabilità. Così, il rumore può provocare disturbi e indurre transizioni di stato (Noise-Induced-Transitions). E' importante notare che una NIT può avere implicazioni profonde sulla vita di un paziente, dal momento che una transizione da uno stato di equilibrio piccolo, nelle dimensioni del tumore, ad uno stato di equilibrio macroscopico, nella maggior parte dei casi significa il passaggio dalla vita alla morte. Generalmente l'approccio standard è quello di modellizzare le fluttuazioni stocastiche dei parametri per mezzo di rumore gaussiano bianco o colorato. In alcuni casi però questa procedura è altamente inadeguata, a causa della illimitatezza intrinseca dei rumori gaussiani che può portare a gravi incongruenze biologiche: pertanto devono essere utilizzati dei rumori "limitati", che, tuttavia, sono molto meno studiati di quelli gaussiani. Inoltre, l'insorgenza di NIT dipende dal tipo di rumore scelto, che rivela un nuovo livello di complessità in biologia. Lo scopo di questa tesi è quello di studiare le applicazioni di due tipi diversi di "rumori limitati" nelle transizioni indotte in due casi: interazione tra tumore e sistema immunitario e chemioterapia dei tumori. Nel primo caso, abbiamo anche introdotto un nuovo modello matematico di terapia, che estende, in modo nuovo, il noto modello di Norton-Simon.
13
Casey, Kathleen. "Noise making subjects /". Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2005. http://wwwlib.umi.com/cr/ucsd/fullcit?p3170240.
Testo completo
14
Frack, Kenneth L. Jr. "Improving transient signal synthesis through noise modeling and noise removal". Thesis, Monterey, California. Naval Postgraduate School, 1994. http://hdl.handle.net/10945/30903.
Testo completoAbstract (sommario):
This thesis examines signal modeling techniques and their application to ambient
ocean noise for purposes of noise removal and for generating realistic synthetic noise
to add to synthetically generated transient signals. Higher order statistics of the noise
are examined to test for Gaussianity. Stochastic approaches to AR, MA, and ARMA
modeling are compared to see which technique yields the "best" synthetic noise. Results
from the modeling process are used to develop a short-time Wiener filter which can be
used to condition a real signal for further processing through effective noise removal.
15
Brock, Scott E. "Device Shot Noise and Saturation Effects on Oscillator Phase Noise". Thesis, Virginia Tech, 2006. http://hdl.handle.net/10919/35099.
Testo completoAbstract (sommario):
Oscillator phase noise is an important factor in designing radio frequency (RF) communications hardware. Phase noise directly contributes to adjacent-channel interference and an increase in bit error rate (BER).
Understanding the operation of an oscillator can help with the oscillator design process. Also, the understanding of the noise processes within an oscillator can add insight to the design process, allowing an intelligent low-noise design. It will be shown that although simulation software can be helpful, the understanding of the oscillator operation is a valuable tool in the design process.
Oscillator design will be discussed, and then the noise processes of the oscillator will be investigated. A new method of decomposing shot noise into in-phase and quadrature components will be discussed. The noise processes discussed for a non-saturating bipolar junction transistor (BJT) Colpitts oscillator will be extended to the case of a saturating BJT Colpitts oscillator. This new method gives insight into the design of low-noise oscillators, and provides guidelines for design of low-noise oscillators. Example oscillators will support the theory and low-noise design guidelines. It will be seen that although designing an oscillator to saturate can provide a stable output level over a wide bandwidth, the added noise production may degrade the performance of the oscillator through both a lower effective Q and restricted signal level compared to the noise.
Master of Science
16
Feng, Jianxiong. "Separation of tread-pattern noise in tire-pavement interaction noise". Thesis, Virginia Tech, 2017. http://hdl.handle.net/10919/76649.
Testo completoAbstract (sommario):
Tire-pavement interaction noise is one of the dominant sources of vehicle noise, and one of the most significant sources of urban noise pollution. One critical generation mechanism of tire-pavement interaction noise is tire tread excitation. The tire tread contributes to the tire-pavement interaction noise mainly through two mechanisms: (1) tread block impact, and (2) the compression and expansion of the air in the tread groove at the contact patch. The tread pattern is the critical part of the tire design since it can be easily modified. Hence, the main focus of this study is to quantify the tread pattern contribution in total tire-pavement interaction noise. To achieve this goal, the noise produced by the tread pattern is separated from the total tire-pavement interaction noise. Since the tread pattern excitation is periodic with tire rotation, the noise produced by the tread is assumed to be related to the tire rotation. Hence, the order domain synchronous averaging method is used in this study to separate and quantify the tread pattern contribution to the total tire-pavement interaction noise. The experiment has been carried out using an On-Board-Sound-Intensity (OBSI) system. Five tires were tested including the Standard Reference Test Tire (SRTT). Compared to the conventional OBSI system, an optical sensor was added to the system to monitor the tire rotation. The once per revolution signal provided by the optical sensor is used to identify the noise signals associate to each revolution.
In addition to the averaging method using optical signals, other data processing techniques have been investigated for separating the tread-pattern noise without utilizing the once per revolution signal. These techniques are autocorrelation analysis, a frequency domain filter, principal component analysis, and independent component analysis.
In the tread-pattern noise generation, the tread profile is the most important input parameter. To characterize the tread profile, the tread pattern spectral content and air volume velocity spectral content for all the five tires are computed. Then, the tread pattern spectrum and the air volume velocity spectrum are both correlated with the separated tread-pattern noise by visual inspection of the spectra shape.Master of Science
17
Gautam, Prashanta. "Investigation of air-borne noise generation mechanisms in tire noise". University of Akron / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=akron148552634330808.
Testo completo
18
Ionescu, Irina Gabriela. "Aircraft noise regulation". Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=82660.
Testo completoAbstract (sommario):
Aircraft noise is one of the most controversial environmental concerns in the aviation industry, partly due to the difficulty in harmonizing countries' regulation regarding this issue. The purpose of this thesis is to analyze the ways in which aircraft noise is regulated at the national and international levels, and to compare the legislative responses to aircraft noise issues in Europe and North America. Each of the four main chapters of the thesis takes into consideration a different aspect of the problem. The first chapter describes the objective and subjective ways of measuring aircraft noise. This process is necessary in order to allow the legislation to meet its purpose, namely, to protect the environment, the sources of the aircraft noise, and the effects of the aircraft noise on people. The second chapter describes the evolution of aircraft noise issues at the national levels in the US and throughout the EU, respectively, as well as at the international level, such as at the ICAO. The third chapter analyses the EU Regulation 925/1999, which created tension between the EU and the US due to its alleged discriminatory nature. This thesis examines the arguments of both sides. Finally, the fourth chapter analyses the noise certification standards developed by ICAO, namely the "balanced approach".
19
Majumdar, Sharanya Jyoti. "Unsteady distortion noise". Thesis, University of Cambridge, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.311216.
Testo completo
20
Strauch, Paul E. "Nonlinear noise cancellation". Thesis, University of Edinburgh, 1997. http://hdl.handle.net/1842/1376.
Testo completoAbstract (sommario):
Noise or interference is often assumed to be a random process. Conventional linear filtering, control or prediction techniques are used to cancel or reduce the noise. However, some noise processes have been shown to be nonlinear and deterministic. These nonlinear deterministic noise processes appear to be random when analysed with second order statistics. As nonlinear processes are widespread in nature it may be beneficial to exploit the coherence of the nonlinear deterministic noise with nonlinear filtering techniques. The nonlinear deterministic noise processes used in this thesis are generated from nonlinear difference or differential equations which are derived from real world scenarios. Analysis tools from the theory of nonlinear dynamics are used to determine an appropriate sampling rate of the nonlinear deterministic noise processes and their embedding dimensions. Nonlinear models, such as the Volterra series filter and the radial basis function network are trained to model or predict the nonlinear deterministic noise process in order to reduce the noise in a system. The nonlinear models exploit the structure and determinism and, therefore, perform better than conventional linear techniques. These nonlinear techniques are applied to cancel broadband nonlinear deterministic noise which corrupts a narrowband signal. An existing filter method is investigated and compared with standard linear techniques. A new filter method is devised to overcome the restrictions of the existing filter method. This method combines standard signal processing concepts (filterbanks and multirate sampling) with linear and nonlinear modelling techniques. It overcomes the restrictions associated with linear techniques and hence produces better performance. Other schemes for cancelling broadband noise are devised and investigated using quantisers and cascaded radial basis function networks. Finally, a scheme is devised which enables the detection of a signal of interest buried in heavy chaotic noise. Active noise control is another application where the acoustic noise may be assumed to be a nonlinear deterministic process. One of the problems in active noise control is the inversion process of the transfer function of the loudspeaker. This transfer function may be nonminimum phase. Linear controllers only perform sub-optimally in modelling the noncausal inverse transfer function. To overcome this problem in conjunction with the assumption that the acoustic noise is nonlinear and deterministic a combined linear and nonlinear controller is devised. A mathematical expression for the combined controller is derived which consists of a linear system identification part and a nonlinear prediction part. The traditional filtered-x least mean squares scheme in active noise control does not allow the implementation of a nonlinear controller. Therefore, a control scheme is devised to allow a nonlinear controller in conjunction with an adaptive block least squares algorithm. Simulations demonstrate that the combined linear and nonlinear controller outperforms the conventional linear controller.
21
Mitchell, Andrew J. "Wind Turbine Noise". Thesis, University of Canterbury. Mechanical Engineering, 2004. http://hdl.handle.net/10092/6622.
Testo completoAbstract (sommario):
The objectives of this thesis were (i) to investigate the main sources and paths of noise on modern utility
size wind turbines; (ii) to explore methods of reducing the noise; (iii) to assess our current ability to
accurately predict and measure wind turbine noise. The accomplishment of these objectives would enable
quieter wind turbines to be developed and allow them to be located near residential dwellings with greater
confidence that the noise would not be a nuisance.
A comprehensive review of the current literature was carried out and the findings were used as a basis for
the investigative work conducted. It was found that wind turbine noise could be classed as either
aerodynamically produced noise or mechanically produced noise. Aerodynamically produced noise on
wind turbines arises mainly from the interaction of the flow over the blade with the surrounding air.
Mechanically produced noise arises from a number of sources such as the gearbox, generator and
hydraulic pumps. The noise can be radiated directly from the noisy component (airborne) and / or
transferred through the structure of the turbine and radiated elsewhere (structure-borne) such as the tower.
The prototype Windflow 500 wind turbine near to Christchurch was used for the majority of the
investigative work carried out, and to assess the predictions made. The main radiators of noise from the
turbine were identified as the blades (86 – 90% of the total sound power), the tower (initially 8 – 12% but
later reduced to ~4% of the total sound power), and the nacelle cladding (1% of the total sound power).
A prominent tone in the sound power spectrum from the turbine was observed in the 315 Hz 1/3 octave
band. This was shown to be predominantly caused by gear meshing in the second stage of the gearbox at
311 Hz. The presence of the tone was significant because under commonly used standards a tonal penalty
would be applied to the measured sound pressure level from the turbine to account for the extra
annoyance caused by the tone. This in turn would mean that any potential wind farms would need to be
sited further from residential dwellings than would otherwise be necessary in order to comply with noise
regulations. Investigations were carried out that addressed the noise radiated from each of the main contributors
outlined above. The sound power level radiated from the tower was found to be effectively reduced by
attaching rubber tiles at strategic locations inside the tower. Noise radiated from the nacelle was reduced
with a combination of acoustic insulation and acoustic absorption inside the nacelle. An investigation
into the gearbox noise was also carried out. Attempts to reduce the tonal noise caused by gear meshing
were made with little success but the investigation provided a good basis upon which to conduct further
work.
Preliminary investigations into both structure-borne and aerodynamically generated blade noise were
carried out. The structure-borne blade noise investigation showed that the blades readily vibrated at a
range of frequencies, the result being that structurally transmitted noise radiated from the blades was
likely to be present at high levels. Research showed that the structure-borne noise radiated from the
blades could be significantly reduced by partially filling the internal cavity of the blades with foam. The
investigation of aerodynamically produced noise was carried out on a section of Windflow 500 blade in
the low noise wind tunnel at the University of Canterbury. The tests showed that the blade generated
noise at a range of frequencies including those in the 315 Hz 1/3 octave band. This suggested that the
tonal noise measured from the blades was not only due to structurally transmitted noise from the gearbox
but was also contributed to by aerodynamically produced noise. It was found that the noise from the
blade section could be reduced by up to 4.5 dB at certain frequencies by attaching serrated strips to the
trailing edge of the aerofoil.
Empirical equations for prediction of wind turbine sound power levels were evaluated and found to be in
good agreement with measured data. It was found that accurate spectral predictions of the sound power
level were much more difficult. However given spectral data for a turbine, it was found that accurate
predictions of the noise propagation from the turbine could be made, taking into account meteorological
effects and the effect of complex topography. It was found that the CONCAWE propagation model was
well suited to the prediction of noise propagation from wind turbines because of its superior handling of
meteorological effects. In an investigation carried out which modelled the Gebbies Pass site of the Windflow 500 it was found that the CONCAWE model could predict sound pressure levels from the
turbine to within 2 dB at distances of up to 1400 m.
Further work in the area of wind turbine noise should be focused on the reduction of blade noise. This is
especially relevant to the Windflow 500 since blade noise was found to be by far the largest contributor to
total noise radiated from the turbine. Acoustic treatments elsewhere would therefore produce only small
reductions in the total sound power emitted by the turbine.
22
彭遠輝 e Yuen-fai Alson Pang. "Managing aircraft noise". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2002. http://hub.hku.hk/bib/B31255280.
Testo completo
23
Leitch, Deborah Starr. "Making visual noise". Master's thesis, University of Central Florida, 2011. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4962.
Testo completoAbstract (sommario):
Focusing on the combination of multi-cultural and historical influences from my personal life experiences, my creations of odd juxtapositions of space, complex pattern and new iconography in my paintings, reveal more than merely a representational image to a viewer. Although my subjects may vary from the anonymous to media celebrity, it is their relationship to me that influences the creation of my static animation and visual noise.ID: 029808799; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Error in paging: p. 7 repeats.; Thesis (M.F.A.)--University of Central Florida, 2011.; Includes bibliographical references (p. 20).
M.F.A.
Masters
Art
Arts and Humanities
24
Morgans, Aimee Sian. "Transonic helicopter noise". Thesis, University of Cambridge, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.615704.
Testo completo
25
Grobbelaar, Johannes Jacobus. "Phase noise measurement". Thesis, Stellenbosch : University of Stellenbosch, 2011. http://hdl.handle.net/10019.1/6806.
Testo completoAbstract (sommario):
Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2011.ENGLISH ABSTRACT: The objective of the thesis is the development of a phase noise measuring system that makes use of crosscorrelation and averaging to measure below the system hardware noise floor. Various phase noise measurement techniques are considered after which the phase demodulation method is chosen to be implemented. The full development cycle of the hardware is discussed, as well as the post processing that is performed on the measured phase noise.
AFRIKAANSE OPSOMMING: Die doel van hierdie tesis is die ontwikkeling van ’n faseruis meetstelsel wat gebruik maak van kruiskorrelasie en vergemiddeling om onder die ruisvloer van die meetstelsel se hardeware te meet. Verskeie faseruis meettegnieke word ondersoek en die fase demodulasie metode word gekies om geïmplementeer te word. Die volle ontwikkelingsiklus van die hardeware word bespreek, sowel as die naverwerking wat toegepas is op die gemete faseruis.
26
Pang, Yuen-fai Alson. "Managing aircraft noise /". Hong Kong : University of Hong Kong, 2002. http://sunzi.lib.hku.hk/hkuto/record.jsp?B2543598x.
Testo completo
27
Lyu, Benshuai. "Installed jet noise". Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/273735.
Testo completoAbstract (sommario):
This thesis studies the prediction and reduction of installed jet noise, combining both analytical and experimental techniques. In the prediction part, it starts with formulating a low-order but robust isolated jet noise prediction model, based on which a remarkably fast code with pre-informed data is developed. A semi-empirical low-order model is then developed to predict installed jet noise. The model consists of two parts, the first of which is based on the Lighthill's acoustic analogy theory. The second part embraces Amiet's approach to model the sound due to the scattering of jet instability waves. It is shown that the significant low-frequency noise enhancement observed in installed jet experiments is due to the scattering of near-field instability waves. The trailing edge scattering model can successfully predict noise spectra at all distinct angles. The quadrupole-induced high-frequency sound is either efficiently shielded at $90^\circ$ to the jet axis on the shielded side or enhanced by around $3$ dB at $90^\circ$ on the reflected side. But these effects gradually diminish as the observer angle decreases. The high-frequency spectra can be robustly predicted at large observer angles while deviation occurs at low observer angles due to jet refraction effects. An experimental study on installed jet noise is then conducted. The effects of plate positions and Mach numbers are studied. Excellent agreement between the experimental results and model predictions is achieved at low frequencies for all plate positions and Mach numbers tested. At high frequencies, the noise spectra at $90^\circ$ on the reflected side can also be correctly predicted. At lower observer angles, deviations occur due to jet refraction effects. In the noise reduction part, an experimental study is firstly carried out to study the effects of lobed nozzles on installed jet noise at constant flow rates. It is found that lobed nozzles do not noticeably change the installed jet noise spectra at low frequencies. However, they do result in a slight noise reduction at high frequencies. To understand why lobed nozzles hardly change low-frequency installed jet noise, an analytical stability analysis for lobed vortex sheets is performed. The results show that lobed jets change both the convection velocity and the temporal growth rate of instability waves. The changes become more pronounced as the number of lobes $N$ and the penetration ratio $\epsilon$ increase. A second set of experiments is carried out to explore the possibility of reducing installed jet noise by using two pylons. The results show that even in the most conservative case installed jet noise is reduced by around $2\sim3$ dB at low frequencies. It is concluded that using two pylons to reduce installed jet noise has significant practical potential.
28
Volstorf, Jenny. "Against all noise". Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät II, 2013. http://dx.doi.org/10.18452/16709.
Testo completoAbstract (sommario):
Für Kooperation via direkte Reziprozität müssen Menschen das Handeln ihrer Partner nachverfolgen, um Ausbeutung zu verhindern. Störungen (d.h. Gedächtnis- oder Wahrnehmungs-/Entscheidungsfehler) beeinträchtigen aber das Nachverfolgen. In meiner Dissertation erkunde ich, ob Strategien zur Modellierung menschlichen Verhaltens kognitiv umsetzbar sind und wie sie mit Störungen umgehen und erforsche umsetzbare störrobuste Alternativen. Tit-For-Tat, berühmtestes Beispiel traditioneller 1-Schritt-Gedächtnis-Strategien, ist nicht störrobust, weil kleinste Störungen seinen Erfolg verringern. Da Störungen alltäglich sind, ist Tit-For-Tat kein ideales Modell menschlichen Verhaltens. Kapitel 1 zeigte hohe Gedächtnisfehlerraten, wenn Versuchspersonen die letzte Handlung ihrer Partner wiedergeben sollten (1-Schritt-Gedächtnis). In einer evolutionären Simulation ging Kooperation bei diesen Raten unter. Sich an die letzte Handlung zu erinnern, ist weder störrobust noch umsetzbar. In Kapitel 2 untersuchte ich, ob Menschen die kognitiv eher umsetzbare Strategie benutzen, ihre Partner in Typen einzuteilen und Kooperierer/Betrüger zu unterscheiden. Verglichen damit, sich die letzte Handlung jedes Partners zu merken, sollte das die Gedächtnisanforderungen senken. Die Ergebnisse deuten an, daß Menschen Partnertypen unterscheiden und ihre Strategie an die Typenverteilung in der Umgebung anpassen. Kapitel 3 erforschte Strategien, die den Vorgang der Einteilung von Partnertypen modellieren, indem sie einen Eindruck bilden. In einer Simulation waren eindrucksbasierte Strategien beim Aufrechterhalten von Kooperation störrobuster als traditionelle Strategien. Auch sagten eindrucksbasierte Strategien Versuchspersonenverhalten besser vorher als traditionelle Strategien. Gewinner von Simulation und Kreuzvalidierung waren jedoch partnerunabhängige Strategien. Menschen scheinen kognitiv noch einfacher umsetzbare störrobuste Strategien zu benutzen.For cooperation to evolve via direct reciprocity, individuals must track their partners’ behaviour to avoid exploitation. Noise (i.e., memory errors or perception/decision errors) compromises tracking, however. In my thesis, I investigate whether strategies proposed to model human behaviour are cognitively feasible and how they cope with noise, and explore feasible noise-robust alternatives. Tit-For-Tat, the most prominent example of 1-step memory strategies, is not robust to noise, because even little noise decreases its success. Since noise is quite common in everyday life, Tit-For-Tat is not an ideal candidate to model human behaviour. Chapter 1 showed that participants, when asked to remember their partners’ previous behaviour (1-step memory), had high memory error rates. In an evolutionary simulation, these rates let cooperation vanish. Remembering a partners’ previous behaviour is neither noise-robust nor cognitively feasible. In Chapter 2, I investigated whether people use the cognitively more feasible strategy of categorizing partners into types, distinguishing cooperators and cheaters. Compared to remembering each partners’ previous behaviour, this would reduce memory effort. The results indicate that people differentiate partner types and adjust their strategy to the proportion of types in their environment. Chapter 3 explored strategies that model the process of categorizing partners into types by building an impression. In a simulation, impression-based strategies were more robust to noise in maintaining cooperation than 1-step memory strategies. A cross-validation of strategies on data from Chapter 2 confirmed that impression-based strategies better predict participants’ behaviour than 1-step memory strategies. The winner of the simulation and the cross-validation were non-contingent strategies, though, indicating that people use cognitively even simpler noise-robust strategies.
29
Arnold, Morgan Jay. "Signals and noise". Thesis, Queensland University of Technology, 1996. https://eprints.qut.edu.au/105542/1/T%28BE%26E%29%201028%20Signals%20and%20noise.pdf.
Testo completoAbstract (sommario):
The broad-based goal of this thesis is to understand, detect, identify and quantify the abstract entity "signal in noise". In general this will be guided by the motivation to extract some form of underlying information, or signal,
from what we observe. Specifically this will involve signal and noise modelling, tackling some of the unresolved issues of signal processing including analysis of non-stationary and multicomponent signals non-Gaussian noise.
Some philosophical background is formulated which explains what ·we mean by the notions of signal and noise that ·we are using. This lays the foundation for some more specific investigations of signal models, noise models and analysis
techniques. Polynomial models for the phase of an analytic signal are first investigated and utilised to optimise some time- domain instantaneous frequency estimation techniques. These techniques, based on phase differencing,
significantly improve performance over traditional methods, such as the central finite difference. A new philosophy towards signal filtering, termed time-frequency peak filtering, is presented. This method is shown to enhance
signals in high noise environments, preserving frequency content far below normal noise thresholds. Good results are obtained for a broad range of non-stationary (general) signals. The effects of non-Gaussian noise are accounted
for by utilising higher-order cumulant information, specifically with a new methodology called higher-order probability distributions. Then we propose to model random variables using characteristic functions and derive
an estimation scheme for these quantities based on kernel functions. As a practical application this methodology is applied to the problem of testing for Gaussianity with results comparative to the best known of such tests.
30
Chau, Pak-lam. "Evaluation on the effectiveness of noise barriers for road traffic noise mitigation /". Hong Kong : University of Hong Kong, 1998. http://sunzi.lib.hku.hk/hkuto/record.jsp?B20038173.
Testo completo
31
Zheng, Haosheng, e Kaichun Zhang. "Noise Analysis of Computer Chassis and Secondary Sound Source Noise Reduction". Thesis, Blekinge Tekniska Högskola, Institutionen för maskinteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-18547.
Testo completoAbstract (sommario):
This article focuses on computer noise analysis and noise reduction processing. With the popularity of computers, people are increasingly demanding the comfort of using computers. Solving the noise problem of the computer case can make the working environment more comfortable. People working in a noisy environment for a long time can cause anxiety and the quality of work is not high. The main purpose of this paper is to analyse the characteristics of computer noise and to reduce the noise of the chassis through the secondary sound source. Through the comparison of the experimental and simulation results, the noise reduction effect of the secondary sound source on the computer case is obtained. This paper can provide a scientific reference for the manufacture of computer chassis and improvement of noise.
32
Pettit, Michael D. "A compreshensive review of the hearing conservation program at XYZ Company". Online version, 2009. http://www.uwstout.edu/lib/thesis/2009/2009pettitm.pdf.
Testo completo
33
Cherukumudi, Dinesh. "Ultra-Low Noise and Highly Linear Two-Stage Low Noise Amplifier (LNA)". Thesis, Linköpings universitet, Elektroniska komponenter, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-71355.
Testo completoAbstract (sommario):
An ultra-low noise two-stage LNA design for cellular basestations using CMOS is proposed in this thesis work. This thesis is divided into three parts. First, a literature survey which intends to bring an idea on the types of LNAs available and their respective outcomes in performances, thereby analyze how each design provides different results and is used for different applications. In the second part, technology comparison for 0.12µm, 0.18µm, and 0.25µm technologies transistors using the IBM foundry PDKs are made to analyze which device has the best noise performance. Finally, in the third phase bipolar and CMOS-based two-stage LNAs are designed using IBM 0.12µm technology node, decided from the technology comparison. In this thesis a two-stage architecture is used to obtain low noise figure, high linearity, high gain, and stability for the LNA. For the bipolar design, noise figure of 0.6dB, OIP3 of 40.3dBm and gain of 26.8dB were obtained. For the CMOS design, noise figure of 0.25dB, OIP3 of 46dBm and gain of 26dB were obtained. Thus, the purpose of this thesis is to analyze the LNA circuit in terms of design, performance, application and various other parameters. Both designs were able to fulfill the design goals of noise figure < 1 dB, OIP3 > 40 dBm, and gain >18 dB.
34
Chau, Pak-lam, e 周栢林. "Evaluation on the effectiveness of noise barriers for road traffic noise mitigation". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1998. http://hub.hku.hk/bib/B31253970.
Testo completo
35
Smith, D. J. "Digital recording and analysis of noise with particular reference to jet noise". Thesis, University of Manchester, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376269.
Testo completo
36
Huber, Jérôme 1978. "Noise propagation model for the design of weather specific noise abatement procedures". Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/40026.
Testo completoAbstract (sommario):
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2003.Includes bibliographical references (p. 105-107).
This thesis presents an aircraft noise prediction simulation that incorporates actual weather in flight dynamics and noise propagation. The rapid prototyping simulation environment NOIse SIMulator (NOISIM) includes a sound propagation model based on a ray tracing algorithm that incorporates atmospheric and ground effects. The simulator uses standard weather profiles, terminal aircraft radar data and flight simulator data as input. NOISIM allows users to explore a wide array of flight procedures and weather conditions to determine the flight procedure that minimizes the noise impact in communities around airports. Two main applications of this tool are presented in this thesis: the design of a weather-specific noise abatement procedure and a statistical study of the effect of weather on average noise contours. The first case study explores the magnitude of the weather effects on the noise impact of a Boeing 767 in communities near Boston Logan Airport during takeoff. It also illustrates how the noise impact can be significantly reduced by changing the departure procedure to capitalize on changes in the weather. The second application is a statistical assessment of the impact of meteorology on annual average contours at major US airports. In this case we test the common assumption used in airport studies that weather effects on noise levels should average out over a year.
by Jérôme Huber.
S.M.
37
Mitani, Tomohiko. "Study on Noise Features of Magnetron and Low Noise Wireless Power Transmission". 京都大学 (Kyoto University), 2005. http://hdl.handle.net/2433/77788.
Testo completo
38
Potts, Adam Simon. "From active to passive noise : rethinking the radicalism of Japanese noise music". Thesis, University of Newcastle upon Tyne, 2014. http://hdl.handle.net/10443/2720.
Testo completoAbstract (sommario):
In recent years noise has gained theoretical momentum as a concept used to consider the complexity of difference in both culture and art. Despite a great degree of variance between its authors, there is nevertheless a common insistence within noise theory that noise must be thought negatively. Particularly in accounts of Japanese noise music, noise is construed as oppositional to musicality and meaning traditionally understood. This thesis aims to reassess this claim with the argument that the true alterity of Japanese noise music cannot be reduced or essentialised to the categories of negativity and radicalism. It will be argued that the language of this music is predicated on a fundamental absence that makes any essential categorisation impossible. Drawing on twentieth-century continental philosophy, particularly the work of Maurice Blanchot, this thesis will develop an entangled relationship between two different, although fundamentally dependent, languages of noise. Chapter one will lay the theoretical groundwork for these languages by distinguishing between active noise and passive noise. If active noise names the language of negativity and radicalism through which we understand the materiality, sonority and performances of Japanese noise music, then passive noise names the way in which this language is problematised by Blanchot's challenge to atomistic and holistic thinking. Chapter two will demonstrate how an intentionless alterity, which constitutes passivity, accounts for a different idea of transgression than the kind frequently attributed to the erotic and sacrificial activities of Japanese noise music. Chapter three will continue this discussion by exploring Japanese noise music's relationship with death and impossibility. The conclusion will examine Blanchot's idea of community as a possible way of understanding the community centred around Japanese noise music. By way of summary, it will be argued that no unifying principle collectivises either the community or language of this music, because both are fundamentally predicated on an irreconcilable impossibility.
39
Tekin, Ahmet. "A low noise analog radio baseband with novel noise shaping circuit techniques /". Diss., Digital Dissertations Database. Restricted to UC campuses, 2008. http://uclibs.org/PID/11984.
Testo completo
40
Boglione, Luciano. "Low noise microwave feedback amplifier design with simultaneous signal and noise matching". Thesis, University of Leeds, 1998. http://etheses.whiterose.ac.uk/900/.
Testo completoAbstract (sommario):
This thesis looks into the problem of simultaneous signal and noise match at the input port of low noise amplifiers; feedback LNAs are considered because previous works show that they can achieve the simultaneous match condition. The investigation analyses the influence of both parallel and series feedback elements on the amplifier. Matrices are used to describe signal and noise parameters of each component of the model - parallel admittance, series impedance, active device. This approach allows the analysis to be applied to a wide range of networks, as long as noise and signal matrices are available. For this reason, the results are not limited to active devices in the microwave region of the spectrum but they are applicable to any linear 2-port circuit. The noise parameters of feedback networks are investigated thoroughly. Analytical expressions are worked out as functions of the feedback immittances and have been used to support experimental evidence previously published. A duality property for feedback networks is pointed out; new circles for constant equivalent noise resistance are devised; optimum values for the feedback impedance are determined; an investigation of a well-known noise model is carried out and its validity is extended. Based on the closed form expressions of the noise parameters, an original analytical procedure for the design of the optimum noise source reflection coefficient is presented. To the author's knowledge, no technique was available before. The design for simultaneous signal and noise match is now possible, because the input reflection coefficient can be set independently by properly choosing the load. Different devices are considered and their different behaviour is highlighted. A remarkable feature of the new design technique is to avoid the need of input matching when designing low noise amplifiers. Finally, experimental results are also presented and the performance of aI GHz single stage BJT LNA is shown. The fundamental achievement is that the noise figure of the LNA is equal to its minimum value within the measurement uncertainty.
41
Lien, Chang-Ming, e 連昶鳴. "Active Noise Cancelling System with Observed Noise Sources and Unobserved Noise Sources". Thesis, 2001. http://ndltd.ncl.edu.tw/handle/29409588214807523620.
Testo completoAbstract (sommario):
碩士國立臺灣科技大學
電子工程系
89
This thesis is mainly devoted to study of active noise cancelling systems. On ideal situations, active noise cancelling systems achieve very good performance. However, a real-word noise canceling systems may have nonlinear and time varying property. The signals involve pass through A/D, microphone, loudspeaker and audio propagating with unknown characteristics, which substantially decrease the system performance. In this thesis, we have considered the effect of secondary path. On the system modeling, which can be by the FXLMS algorithm. An off-line scheme and an on-line scheme have been delivered to estimate unknown secondary path. In this thesis, we propose a noise cancelling system scheme with both observed and unobserved noise sources. This system has three adaptive filters that are compensation, noise canceling and predictor. In such noise canceling system, the observed noise sources mainly deliver sensor, which passes through an adaptive filter to extract the noise component in original signal. As for unobserved noise sources, noise estimated schemes are utilizing adaptive predictor to reduce noise component. This system structure utilizes Matlab that simulates to identify performance and property.
42
Azhar, Athiba M. "Studies on quantum noise and burst noise". Thesis, 1992. http://hdl.handle.net/2009/1490.
Testo completo
43
Tsai, Cheng-lung, e 蔡政龍. "Noise Analysis and Low Noise Amplifier Implementation". Thesis, 2007. http://ndltd.ncl.edu.tw/handle/33450042710218931896.
Testo completoAbstract (sommario):
碩士國立雲林科技大學
光學電子工程研究所
95
In this thesis，we employed the TSMC 0.18um CMOS processes and TSMC 0.35um SiGe processes to design and implement the low noise amplifiers. Among these amplifiers, three circuits are suitable for the applications of IEEE 802.15.3a ultra wide band standard. The low noise amplifier is a key component for the front end of receivers. Sufficient gain, low noise, good input and output matching, low power consumption are important performances of a low noise amplifier. The feedback topology is generally used in my design. By this way, gain flatness and input matching can be attained. Especially, the broadband matching is very difficult in the input terminal. Input impedance matching and noise matching are usually trade-off. Though feedback topology decreases the gain, but the intrinsic gain of modern active devices is enough to face the persecution. Another circuit is a 24GHz low noise amplifier, using the common gate topology as the input stage. By the Common Gate Resister Feedback (CGRF) skill, we can suppress noise of the first stage and then overall noise can be lower. In the first chip, a folded-cascode 3-5GHz UWB LNA is designed with feedback technologies to enhance gain flatness. The area of the chip is 1.21 mm × 1.15 mm. In the second chip, a 24GHz LNA is implemented by using three-stage technology. In addition, noise contribution of the first stage is analyzed. The whole area of the chip is 1.08 mm × 0.96 mm. In the third chip, the TSMC 0.35um SiGe processes is used to implement a current-reused LNA. The feedback topology is added to attain the gain flatness. The whole area of the chip is 1.26 mm × 1.18 mm. In the fourth chip, the traditional cascode technology with feedback technology is used to attain the input matching. In addition, the body-biasing technology is used to enhance the MOS tranconductance. The area of the chip is 1.27 mm × 1.12 mm.
44
Li, Cheng-Hung, e 李政鴻. "Noise Decoupling System and Low Noise Amplifier". Thesis, 2010. http://ndltd.ncl.edu.tw/handle/57013953093420825203.
Testo completoAbstract (sommario):
碩士臺灣大學
電子工程學研究所
98
Noise usually causes signal distortion, thus degrading the circuit performance. In this thesis we discuss various sources of noise and the models of the substrate and power line at first. Then, a noise decoupling circuit is implemented using the PSC (Powerchip Semiconductor Corp.) high voltage process. The circuit has noise select, noise sources and the noise decoupling system. There are two types of experiments. First, on-chip noise sources are used to generate the internal noise. The magnitude of the substrate noise and power noise are measured with the noise decoupling system activated or deactivated. Then an external noise is applied through bias-T to observe the efficiency of noise suppression. There is about 40% reduction of noise. Secondly, a 5.8G low noise amplifier with an active inductor and noise decoupling system is implemented using 0.35um CMOS process. An active inductor is adopted to reduce chip area and costs. As to noise decoupling, it could reduce the noise figure of the LNA, so the circuit has better performance. The LNA exhibits input matching less than -11 dB, output matching less than -11 dB, 18 dB gain, 2.8 dB noise figure, -4 dBm IIP3, and 25 mW power consumption. Finally, an 8-12 GHz X-band broadband amplifier is implemented using 90 nm CMOS process. On-chip probing is used to measure the performance of the LNA. A shunt-feedback resistor and noise cancellation method are used in the amplifier designed to lower the noise figure. The LNA exhibits input matching less than -10 dB, output matching is less than -10 dB, 11dB gain, 2.5~4 dB noise figure, -7 dBm IIP3, and 8 mW power consumption.
45
Chen, Kuan-Hsun, e 陳冠勳. "Active Noise Control for Duct Noise Cancellation". Thesis, 2018. http://ndltd.ncl.edu.tw/handle/y9a2j5.
Testo completoAbstract (sommario):
碩士中原大學
電機工程研究所
106
This thesis applies active noise control techniques to cancel large fan noise and white noise in a duct. A probe-tube microphone is designed for measuring noise in windy environment to avoid wind interference. We apply feedforward, feedback, hybrid and using FIR filters with feedback neutralization, and IIR filters with feedback neutralization algorithms for the experiments. Really time experimental results show the performance of the white noise cancelation in the duct is 18 dB(A), and 15dB(A) for the fan noise.
46
Huang, Po-Chin, e 黃柏欽. "Impulse Noise Removal with Boundary-Based Noise Detection and Median-Based Noise Replacement". Thesis, 2009. http://ndltd.ncl.edu.tw/handle/07024164008337257057.
Testo completoAbstract (sommario):
碩士朝陽科技大學
資訊工程系碩士班
98
This thesis presents a novel impulse noise removal approach to improve the quality of restored image. Presently, noise removal approaches generally consist of two stages: noise detection and noise replacement. In the stage of noise detection, a noisy pixel is identified. If a noisy pixel is detected, a noise replacement scheme is applied to replace the noisy pixel with un-noisy one. When the pixel is uncorrupted, then leave it intact. A well-known noise detection scheme is the boundary discriminative noise detection (BDND). The performance of BDND is heavily dependent on the accuracy of boundary detection. When the boundaries are not determined appropriately, then the noisy pixel will be shown in the restored image. To improve the detection performance of BDND, two modified BDND are proposed in this thesis. They are called MBDND_1 and MBDND_2, respectively. In the MBDND_1, a modification is made on the inequalities of BDND while a boundary resetting scheme is applied in the MBDND_2. Besides, a novel noise detection scheme called the noise detection based on estimated noise distribution (NDEND) is presented and shown having much better detection performance than the BDND, the MBDND_1, and the MBDND_2. As for the noise replacement, a class of adaptive neighborhood median filters (ANMF) is introduced. Note that the window size used in the filtering process has smoothing effect on the restored image. That is, larger windows applied in the filtering process result in a stronger smoothing effect on the restored image. Thus, the proposed ANMF employs smaller windows, when replacing noisy pixels, for better visual quality of a restored image, especially in high noise density cases. To justify the proposed NDEND and ANFM, several images are given where the salt and pepper noise, the random-valued noise, and the unbalanced density noise, with various densities are under study. Besides, the results obtained from the NDEND/ANFM are compared with the well-known boundary based approach BDND. It indicates that the proposed NDEND/ANFM generally has better performance than that in the BDND both in objective and/or subjective assessments.
47
Yao, Hu-Kai, e 胡凱堯. "Noise Analysis of Ultra Wideband Low Noise Amplifier". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/48539857582380565023.
Testo completoAbstract (sommario):
碩士中原大學
電子工程研究所
102
In this paper, based on the existing ultra wideband low noise amplifier architecture discussed noise response. Considering the noise source of the main circuit, including resistance thermal noise and MOS thermal Noise, the noise model from the thermal noise generated by these components. The implementation of ultra wideband low noise amplifier circuit equivalent to the noise model circuit, get the most simple noise circuit, in order to facilitate the circuit noise analysis. The ultra wideband low noise amplifier was implemented in TSMC 0.18μm CMOS process. An ultra wideband 2.7 to 10.8 GHz low noise amplifier and the power consumption is 18mW in a 1.8 V power supply. The measured results are: the gain (S21) ranges from 10.5dB-13.4dB, the noise figure (NF) ranges from 3dB-4.64dB, the Input reflection coefficient (S11) under the -5.3dB, the Output reflection coefficient (S22) under the -4.79dB, the 1db Compression Point (P1dB) is -6dBm, the input third-order intercept point (IIP3) is -2.5dBm. The active layout area is 0.419 mm2.
48
Shih, Yi-Cheng, e 施宜成. "Active Noise Cancellation for Magnetic Resonance Imaging Noise". Thesis, 2001. http://ndltd.ncl.edu.tw/handle/63492266939442540909.
Testo completoAbstract (sommario):
碩士國立臺灣大學
電機工程學研究所
89
Magnetic Resonance Imaging (MRI) is one of the fast growing technology in medical imaging. With its non-radioactive, and non- invasive properties, MRI has contributed to a tremendous advance in medical diagnosis technology. However, it still has some limitations and problems. The loud acoustic noise generated by gradient switching is annoying patients. According to researches, noise generating by clinical MRI would up to 100dB. When using the rapid imaging method- echo-planar imaging (EPI), it will have more serious acoustic problems, because of higher slew rate and duty cycle. A simpler and perhaps more widely used technique is the use of ear plugs but this method seems to protect only against sounds transmitted by the auditory canal to the ear. The use of passive ear protection is not a complete solution. In general, high frequency components are adequately suppressed by around 20 dB by ear protection. But it doesn’t have such a good effect at low frequencies. Thus, we use active noise cancellation method to solve this problem. The results of simulation show that the average attenuation level is about 18.23dB in the pulse sequences of spin echo, about 17.82dB in the pulse sequences of gradient echo, and about 20.73dB in the pulse sequences of EPI. In hardware implementation, we constructed a DSP system for active noise cancellation to cancel the noise of EPI in real-time. Due to the speed limitation of current system, the noise is attenuated at the noise level of 5.035 dB. In the future, with higher speech CPU or DSP I/O capability, we are able to solve the time-delay problem for much better noise reduction. Keyword：Active Noise Cancellation、Magnetic Resonance Imaging
49
Nicholls, Rob. "White Noise". Thesis, 2012. http://hdl.handle.net/10012/6775.
Testo completoAbstract (sommario):
Abstract
The paintings in White Noise are a response to temporal lighting conditions that occur at night. A discussion of sensory affect demonstrates how perception is inextricably connected to the body’s sensory capabilities such as sound and touch. By examining Maurice Merleau-Ponty’s theory of phenomenology and looking at Gestalt Psychology based experiments it is made clear that seeing whole and complete forms in the world is a product of embodied perceptual experience. I recall early experiences of being affected by light describing the optical illusion of the afterimage and then move into the everyday perceptions that inform my current painting practice.
The painting studio process is examined as a beacon from which to reconcile the affecting nuances of observed lighting at night. I discuss the importance of allowing trial, error and patience to take place while making paintings to in turn seek out optimal colour relationships and shape interaction. By developing a specific painting vocabulary that responds to the colour, texture and sound associated with perceptual experiences I reconcile through the abstract process of painting how affecting experiences can be re-presented and reinvented onto the canvas.
50
Flores, Maria Gabriela. "White noise". Thesis, 2007. http://hdl.handle.net/1911/20552.
Testo completoAbstract (sommario):
The image of our metropolis is the product of our economy. Commercial vernacular architecture in the United States since 1950 has become increasingly generic and anonymous. This is the direct result of a shift in proprietorship from individual to joint ventures in ownership of built form. Joint ventures in ownership, in turn, allow for an increase in the scale of built form, or 'bigness,' which dislodges or shifts the fundamental architectural volume or unit. This new unit appears on frontage roads across the nation, and Houston's own 'feeder' roads are a prime example of this changing space of American cities.