Tesi sul tema "Noise suppression"
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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 completocui, qiaofeng. "Suppression of impulsive noise in wireless communication". Thesis, Högskolan i Gävle, Avdelningen för elektronik, matematik och naturvetenskap, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-18270.
Testo completo6
Hebert, Robert Carleton University Dissertation Engineering Electrical. "Background acoustic noise suppression in mobile telephony". Ottawa, 1990.
Cerca il testo completoVilidaite, Greta. "Neural noise and suppression in visual processing". Thesis, University of York, 2017. http://etheses.whiterose.ac.uk/19685/.
Testo completoEvernham, Jeffrey Thomas. "Acoustic noise suppression for helicopter communication systems". Thesis, Massachusetts Institute of Technology, 1992. http://hdl.handle.net/1721.1/42553.
Testo completoMessing, David P. (David Patrick) 1979. "Noise suppression with non-air-acoustic sensors". Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/87444.
Testo completoIncludes bibliographical references (leaves [74]-[75]).
by David P. Messing.
S.M.
Etter, Walter. "Contributions to noise suppression in monophonic speech signals /". [S.l.] : [s.n.], 1993. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=10210.
Testo completoRodda, Lasya. "Baseband Noise Suppression in Ofdm Using Kalman Filter". Thesis, University of North Texas, 2012. https://digital.library.unt.edu/ark:/67531/metadc115147/.
Testo completoVishal, Kumar. "Incoherent noise suppression and deconvolution using curvelet-domain sparsity". Thesis, University of British Columbia, 2009. http://hdl.handle.net/2429/8843.
Testo completoZhang, Yang. "Phase noise suppression techniques for 5-6GHZ oscillator design". Online access for everyone, 2007. http://www.dissertations.wsu.edu/Thesis/Fall2007/y_zhang_113007.pdf.
Testo completoShou, Xingxian. "The Suppression of Selected Acoustic Noise Frequencies in MRI". Case Western Reserve University School of Graduate Studies / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=case1281404517.
Testo completoDandu, Sai Venkata Satya Siva Kumar, e Sujit Kadimisetti. "2D SPECTRAL SUBTRACTION FOR NOISE SUPPRESSION IN FINGERPRINT IMAGES". Thesis, Blekinge Tekniska Högskola, Institutionen för tillämpad signalbehandling, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-13848.
Testo completoHung, Chih-Pin. "Signal enhancement based on multivariable adaptive noise cancellation". Thesis, University of the West of Scotland, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.294663.
Testo completoPing, Pau Kwok. "Systematic studies on noise control of plastic injection moulding machine". Thesis, University of Warwick, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265624.
Testo completoGreen, Donald R. "The utility of higher-order statistics in Gaussian noise suppression". Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2003. http://library.nps.navy.mil/uhtbin/hyperion-image/03Mar%5FGreen.pdf.
Testo completoThesis advisor(s): Charles W. Therrien, Charles W. Granderson. Includes bibliographical references (p. 123). Also available online.
Thiemann, Joachim. "Acoustic noise suppression for speech signals using auditory masking effects". Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=31073.
Testo completoPetrovic, Denis [Verfasser]. "Phase Noise in OFDM : Characterisation, Estimation and Suppression / Denis Petrovic". Aachen : Shaker, 2005. http://d-nb.info/1186589124/34.
Testo completoZou, Yuexian, e 鄒月嫻. "Robust statistics based adaptive filtering algorithms for impulsive noise suppression". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2000. http://hub.hku.hk/bib/B22823736.
Testo completoabstract
toc
Electrical and Electronic Engineering
Doctoral
Doctor of Philosophy
Zou, Yuexian. "Robust statistics based adaptive filtering algorithms for impulsive noise suppression". Hong Kong : University of Hong Kong, 2000. http://sunzi.lib.hku.hk/hkuto/record.jsp?B22823736.
Testo completoYe, Sheng. "Phase realignment and phase noise suppression in PLLs and DLLs /". Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2003. http://wwwlib.umi.com/cr/ucsd/fullcit?p3091345.
Testo completoWu, Qing, e Lu-yu Yang. "Analysis and Suppression of Power Supply Noise for Airborne Telemetering Transmitter". International Foundation for Telemetering, 2009. http://hdl.handle.net/10150/606023.
Testo completoDuring the program researching on airborne telemetering transmitter of a certain remote telemetry system, small size and a variety of voltage on board are design difficulties. Due to the above important factors, the performance of power supply makes a big affect to the parameters of BPSK modulated signal, especially the EVM (Error Vector Magnitude). The author analyzes the cause of power supply noise and puts forward some suggestions to damp the noise. With these methods, the EVM of modulated signal is improved. Finally, we can conclude the related principles about the suppression of power supply noise.
Demiroglu, Cenk. "Multisensor Segmentation-based Noise Suppression for Intelligibility Improvement in MELP Coders". Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/10455.
Testo completoHu, Rongqiang. "Multi-Sensor Noise Suppression and Bandwidth Extension for Enhancement of Speech". Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/10452.
Testo completoHunter-Jones, Nicholas R. "Novel approaches to Newtonian noise suppression in interferometric gravitational wave detection". Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/65529.
Testo completoCataloged from PDF version of thesis.
Includes bibliographical references (p. 63-65).
The Laser Interferometer Gravitational-wave Observatory (LIGO) attempts to detect ripples in the curvature of spacetime using two large scale interferometers. These detectors are several kilometer long Michelson interferometers with Fabry-Perot cavities between two silica test masses in each arm. Given Earth's proximity to various astrophysical phenomena LIGO must be sensitive to relative displacements of 1018 m and thus requires multiple levels of noise reduction to ensure the isolation of the interferometer components from numerous sources of noise. A substantial contributor to the Advanced LIGO noise in the 1-10 Hz range is Newtonian (or gravity gradient) noise which arises from local fluctuations in the Earth's gravitational field. Density fluctuations from seismic activity as well as acoustic and turbulent phenomenon in the Earth's atmosphere both contribute to slight variations in the local value of g. Given the direct coupling of gravitational fields to mass the LIGO test masses cannot be shielded from this noise. In an attempt to characterize and reduce Newtonian noise in interferometric gravitational wave detectors we investigate seismic and atmospheric contributions to the noise and consider the effect of submerging a gravitational wave detector.
by Nicholas R. Hunter-Jones.
S.B.
Ling, Matthew K. "Structure and design optimisation of composites for noise suppression in vehicles". Thesis, Sheffield Hallam University, 1992. http://shura.shu.ac.uk/19964/.
Testo completoMcCoy, Anoma Dayawansa. "Intensity noise suppression using a semiconductor optical amplifier : characterisations and applications". Thesis, University of Southampton, 2005. https://eprints.soton.ac.uk/65501/.
Testo completoBadenhorst, Scott James. "Acceleration of the noise suppression component of the DUCHAMP source-finder". Master's thesis, University of Cape Town, 2015. http://hdl.handle.net/11427/15507.
Testo completoRundström, Per. "Thermal Properties of a 5G Telecom Equipment Casing Design for Noise Suppression". Thesis, KTH, Skolan för industriell teknik och management (ITM), 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-299742.
Testo completoRunt om i världen pågår implementeringen av 5G-mobilnätet. Med den senaste generationens mobila dataöverföring kommer många nya fördelar jämfört med tidigare generationer. En nackdel är däremot den kortare räckvidden hos signalen på grund av den högre frekvens som sänds ut av radion. Ett sätt att kringgå detta är att placera mindre radior närmare där användaren befinner sig. Detta examensarbete utgår från en sådan radio och eftersom den kyls med fläktar och ska placeras nära där människor bor och vistas är det fördelaktigt att kunna sänka ljudet som når omgivningen. Därför har ett ljudisolerande hölje utvecklats med plats för tre telekomradior med syfte att sänka den totala A-vägda ljudeffektnivån som når dess omgivning. För att åstadkomma detta användes kanaler i kombination med mikroperforerade plåtar (MPPs) tillsammans som ett ljuddämpande element. Som ett verktyg i designprocessen och för att säkerställa att radions komponenter inte blev för varma gjordes en CFD-simulering. Resultatet av simuleringen verifierades även med ett experiment där temperaturen hos radions kylflänsar mättes under olika fläktvarvtal. När den totala A-vägda ljudeffektnivån mättes för höljet tillsammans med tre radior uppstod en sänkning med mellan 11,6 dB(A) och 14,2 dB(A) beroende på aktuellt fläktvarvtal. Resultatet från experimentet visade även att temperaturen på radions kylfläns höjdes med mellan 2,8 och 5,9 °C beroende på fläktvarvtal, med mindre skillnad för högre fläktvarvtal vid jämförelse med radions temperatur vid drift utan hölje. Resultaten anses visa på den goda potentialen av att använda höljen utrustade med mikroperforerade plåtar för att minska överfört ljud från telekomradior.
Andersson, David. "Acoustic properties of a 5G Telecom Equipment Shroud Design for Noise suppression". Thesis, KTH, Marcus Wallenberg Laboratoriet MWL, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-302267.
Testo completoAllt eftersom tekniken går framåt tenderar den att också förbruka mer och mer energi som i sin tur måste kylas av kraftigare och mer högljudda fläktar, detta fenomen är särskilt påtagligt när det kommer till den senaste generationens radioutrustning för 5G. Detta examensarbete är ett samarbete mellan KTH och Ericsson med avsikt att skapa en kåpa som är designad för att innesluta ett bestämt antal 5G radiomoduler. Denna kåpa ska i så stor utsträckning som möjligt dämpa det fläktinducerade bullret. I det här projektet nyttjas kanaler med ljuddämpare vid ändarna som dämpar ljudet med hjälp av Cremerimpedans, dvs: den väggimpedans som optimalt dämpar en akustisk mod. För att kunna förutspå resultatet skapades en förenklad akustisk modell i ett FEM program. Resultatet från denna modell jämförs sedan med ljudeffektnivån från slutmätningen av den färdiga kåpan. Resultatet från slutmätningen visar att kåpan lyckas sänka radioenheternas totala ljudeffektnivå med 13 dB(A) samtidigt som en temperaturökning på mellan 2.8°C och 5.9°C erhålls. Det här resultatet bedöms vara en framgång, vilket leder till slutsatsen att ljuddämpning med användning av Cremerimpedans rekommenderas för vidare arbete.
Canagarajah, Cedric Nishanthan. "Digital signal processing techniques for speech enhancement in hearing aids". Thesis, University of Cambridge, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260433.
Testo completoShu, Chin-wei, e 許靜葳. "Suppression of Cleaning Jet Noise". Thesis, 2004. http://ndltd.ncl.edu.tw/handle/11147361962515200107.
Testo completo大仁科技大學
環境管理研究所
94
The purpose of this study is to investigate the noise-generating Mechanisms of industrial cleaning jets and to offer possible strategies for the suppression of the generated noise. A set of 6mm-diameter open pipe Nozzles with various lengths and fixtures are used in the experiments. Steel meshes with different densities are used to control the internal turbulences inside the nozzles. It is found that, without adequate control measures, the turbulence existing in the air before it leave the nozzle might be the dominant one among the noise-generating mechanisms, exceeding the widely-studied mixing noise by a large margin. Steel meshes are shown to be an effective tool for the control of the internal turbuence levels.
"Robust wavelet thresholding for noise suppression". Massachusetts Institute of Technology, Laboratory for Information and Decision Systems, 1996. http://hdl.handle.net/1721.1/3446.
Testo completoCover title.
Includes bibliographical references (p. 4).
Supported in part by the Army Research Office DAAL-03-92-G-115 Supported in part by the Air Force Office of Scientific Research. F49620-95-1-0083, BU GC12391NGD
Rong, Chuang Ruey, e 莊瑞榮. "Speech noise suppression with kalman filter". Thesis, 2000. http://ndltd.ncl.edu.tw/handle/67819278216026490277.
Testo completo國立成功大學
電機工程學系
88
With great advance in speech science and the advent of digital cellular telephone, the role of noise suppression in speech processing problems such as speech enhancement and speech recognition has taken on an increased importance. We present a noisy speech model and propose an approach for speech noise suppression. This approach adopts the treating technique for speech with Kalman filter and the spectral subtraction method. It takes the advantage of Kalman filtering method to raise the quality of the treated speech with high-speed variance of noises and eliminates the errors produced by the measuring process and the advantage of spectral subtraction method to reduce the noise level. Experimental results demonstrate the good performance in reducing noise level and lowering distortion of parameter for speech recognition. The performance of our design to treat non-stationary noise is also better than the spectral subtraction method.
Jung-Fang, Tsai, e 蔡榮芳. "TDMA noise suppression for mobile device". Thesis, 2011. http://ndltd.ncl.edu.tw/handle/vgb3kn.
Testo completo國立臺北科技大學
電腦與通訊研究所
99
This thesis introduce how to analysis microphone components, capacitor components, microphone''s input circuit and major noise of cell phone first. The system noises include power noise, cross talk and wireless noise. The TDMA noise of microphone circuit , the normally solve method is to use single end for the input circuit of microphone. To compare the difference of voice quality between differential input and single end input and analysis it with method of theory . In order to solve TDMA noise issue, the thesis will provide the method of complex filter circuit and then do the simulation and measurement of capacitor . By the experiment, it can help us to understand how to choose the best component to solve TDMA noise. To measure the performance of complex high-pass-filter circuit with the high TDMA noise condition and this will help us how to get best performance from high-pass-filter circuit. Finally, we will compare the voice performance with the single end input circuit and differential input circuit for the TDMA noise suppression.
Lee, Zong-Wei, e 李宗委. "Study of Noise Suppression Materials on the Harmonic Suppression of Filters". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/krz78h.
Testo completo義守大學
電子工程學系
102
This study investigates the effect of magnetic Fe3O4 and Ag conductive material mixing with ITK epoxy on the noise suppression of bandpass filters. The bandpass filters is based on half wavelength resonators . The simulator HFSS was employed to simulate the characteristics of filters and the simulated results were compared with experimental results . It is found that the center frequency of filters is not affected after the coating of noise suppression materials ; however , the harmonic of the filters is suppressed with the cated films.
Tu, Ming-Hsien, e 杜明賢. "Standard Cell Library Noise Characterization and Power Noise Suppression Circuit Design". Thesis, 2006. http://ndltd.ncl.edu.tw/handle/83733414797860377311.
Testo completo國立中央大學
電機工程研究所
94
Abstract With advances in semiconductor fabrication technology, the minimum feature size continues to decrease and the circuit density increases gradually. At the same time, increasing clock speeds demands these circuits to switch at faster rates. Thus, noise generation becomes more and more serious in today’s high-speed circuits. Moreover, decreasing power supply voltages dictate lower transistor threshold voltage. Therefore, noise margins of circuits become smaller. It causes a significantly signal-to-noise ratio reduction for both digital and mixed-signal/analog circuits. Therefore, the circuit performance will be limited by noise. In this thesis, we provide a noise-aware standard cell library. There are two major parts in the subject, noise characterization and noise suppression cell design. On noise characterization, we introduce the procedure to characterize the noise behavior and use CLKINVX1 and NAND2X1 as a characterization example. We also discuss the way to characterize simultaneous switching noise and propose some preliminary ideas. On noise suppression cell design, we implement the passive power supply noise (PSN) suppression cell, decoupling capacitance, and an active PSN suppression module. They can be used to suppress PSN occurring in design’s circuit. The simulation results appeal that the active PSN suppression circuit can have 33% reduction for negative PSN peak and 44% reduction for positive PSN peak. Finally, we combine the active PSN suppression circuit with an on-chip bounce measurement circuit. This combined circuit can let us observe the improvement due to the active PSN suppression circuit directly.
Yang, Pei-Yao, e 楊焙堯. "Study of Noise Suppression in Electromagnetic Flowmeters". Thesis, 2007. http://ndltd.ncl.edu.tw/handle/03257729019961898768.
Testo completo國立成功大學
電機工程學系碩博士班
95
Because the electromagnetic flowmeter uses the Faraday’s Law to generate tiny voltage to convert into the flow rate, it has obvious influence on the noise and external interference for measurement’s accuracy. This thesis investigates the method how to suppress the interference. At first the applications and fundamental principle of the electromagnetic flowmeter is given, and followed by the discussion of the factors associated with the operating of system. In the excitatory magnetic driver, first choosing proper exciting method, then suppress the interference which is generated by this excitatory method via choosing the exciting frequency. In the signal circuit, it is processed through filtering, amplifying, and avoiding magnetic interference by sampling technology. Finally, this system obtains a voltage at output of signal circuit. It can be certified that the purpose of the output voltage proportional to the flow is achieved through the experimental results.
LO, Shun-Teng, e 羅順騰. "Blocking Noise Suppression Schemes for JPEG Images". Thesis, 2002. http://ndltd.ncl.edu.tw/handle/77855472324138344824.
Testo completo國立交通大學
電機與控制工程系
90
The image compression by JPEG is very common in our daily life, for example, Internet or the digital camera. JPEG, itself, is a standard of image compression to decrease the data rate. Unfortunately, annoying blocking artifacts would appear. The blocking noise makes us uncomfortable usually. It is necessary and important to remove the blocking noises. The thesis introduces several schemes for the JPEG blocking noise removal: the noise discussed here is the blocking noise resulted from the quantization of DCT coefficients. Traditionally, different filters are applied respectively to the monotone area and the edge area, aiming at smoothing the monotone area or enhancing the edge area. We propose two methods to remove the blocking noise. The first one is the use of the fuzzy rule-based filter (FRB). The fuzzy rule-based filter’s output is a weighted average the processing pixel itself and its neighborhood pixels, dependent on the gray level difference between pixels, the spatial distance and direction between pixels, and the variance in the local window. Using the LMS learning algorithm we can determine the best membership function for the FRB filter. For the second method, we only deal with pixels around the block boundaries, letting the pixels not so blocky. By the simulation results, we have demonstrated the effectiveness and robustness in blocking noise removal our proposal schemes.
Chen, Yu-Cheng, e 陳昱丞. "Impulse Noise Suppression for DVB-T System". Thesis, 2007. http://ndltd.ncl.edu.tw/handle/83190096339841540147.
Testo completo國立中央大學
通訊工程研究所
95
Impulse noise is a kind of noise with short duration and strong interference. It comes from switching on/off electric appliances or the duration of using them. In practical communication system, impulse noise usually causes received signal to distort. If received signal needs the former signal to demodulate the instant signal, impulse noise will influence the later signal. DVB specification defines six different test patterns[2] for impulse noise. This thesis research content is simulation on different DVB-T specification with these test patterns. This thesis first talks about impulse noise detection including convention algorithm, proposed algorithm and then talks about impulse noise cancellation including convention algorithm, S. V. Zhidkov proposed algorithm, this thesis proposed algorithms Least Square (LS) and Search Over Quantization Level (SOQL). By simulating all these algorithm can find that proposed algorithm can effective reduce influence of impulse noise.
HO, SHENG-TSUNG, e 何昇聰. "Impulse noise suppression for DS-CDMA system". Thesis, 2005. http://ndltd.ncl.edu.tw/handle/08425853292036078772.
Testo completo國防大學中正理工學院
電子工程研究所
93
In this thesis, we investigate the techniques for suppressing impulse noise in a direct-sequence code division multiple access (DS/CDMA) communication system. Firstly, we introduce three common impulse noise models—Gaussian Mixture, Middleton Class A and Alpha-Stable distribution, which are proven to best describe the noise characteristic in various physical environment, such as radar, underwater acoustic, radio channels, local networks, wireless and power line communications. Several multiuser detection techniques based on robust regression are explored to combat impulsive noise in DS/CDMA communication systems detection techniques, the adaptive parametric decorrelator is shown to have notable merits for suppressing impulse noise in a varied communication. By choosing proper basis functions, the parametric detector can adjust itself to effectively suppress the impulse noise. Simulations show that the performance approaches to the optimum in the three kinds of impulsive noise environments.
Liou, Tau-Chian, e 劉陶謙. "Duct Noise Suppression Using Passive Silencing Techniques". Thesis, 2015. http://ndltd.ncl.edu.tw/handle/yzfknd.
Testo completo國立臺灣海洋大學
機械與機電工程學系
103
This study aims to investigate the noise emitted by the machine’s inlet and outlet ports, with the quarter-wave resonator and the Herschel-Quincke tube applied for noise suppression. Finite element simulation is conducted for the cavity and the duct for sound transmission loss analysis. The ways to achieve broadband silencing effect are examined for a specified noise frequency. By increasing the cross-sectional area due to the increase in the number of silencers used, performance of both the quarter-wave resonator and the Herschel-Quincke tube is improved. The quarter-wave resonator is superior to the Helmholtz resonator in that the former only requires the tube length to be specified, whereas the latter requires the design of the cavity volume which is affected by the neck area chosen. The quarter-wave resonator is applied in the experiment for noise suppression of a portable vacuum cleaner. The silencer is created using the 3D printing technology. Because it is difficult to print a large model using 3D printing, the shape of the resonator is revised accordingly, which results in slight deviation of the originally designed main frequency. However, the performance is not severely affected due to the broadband design. Experimental study includes the traditional sound pressure measurement, three- microphones, and four-microphone measurements. Based on the observation of both the experiment and computer simulation, it is demonstrated that Herschel-Quincke tube is more effective than the quarter-wave resonator in terms of effective band width and actual implementation. Noise suppression of a hand dryer is thus conducted using the Herschel-Quincke tube.
Chen, Chih-Neng, e 陳智能. "Filter design for suppression of noise propagation". Thesis, 2004. http://ndltd.ncl.edu.tw/handle/22880719001430544958.
Testo completo國立臺灣大學
電機工程學研究所
92
This thesis outlines the design and development of filters applies to medical electronic devices, which leads to a better design and rapid development architecture for the inhibition of electromagnetic interference (EMI). The EMI referred included the device induced and those that existed in our environment. The filters have been constructed with the objective of preventing incorrect data acquisitions and measurements due to the EMI and will increase the reliability and precision of such devices. A comprehensive introduction of the EMI induced noise and their transmission route is revealed along with a thorough analysis and configuration of an existing consumer product. The new method proposed has greatly reduced the time required for research and design resulting from the fact that adjustments to eliminate noise would no longer be necessary after the design is completed. Recurrent corrections avoided would then accelerate the promotion of the newly designed device into the consumer market. The implemented filter undergoes laboratory tests, simulations and functional corrections in order to meet all EMI regulations. The final product not only meets the anticipated results, but also gives designers in the field of medical electronic devices a better solution for EMI reductions.
Wu, Tzong-Yow, e 吳宗佑. "Study of DSP-Based Suppression Conducted Noise". Thesis, 1999. http://ndltd.ncl.edu.tw/handle/27135902686915624638.
Testo completo國立成功大學
電機工程學系
87
In the thesis, a device is developed to decipher commode-mode noise and differential-mode noise from a conducted EMI noise measurement, its basic principles of the separator will be described. Based on the analysis of the conducted EMI source and equivalent circuit, an simplify design process and suitable EMI filter is described for a single-phase active power filter. Otherwise, an active noise filter is also designed based on digital signal processor. Since it is difficult to know the exact noise component, so adaptive filter theory is the most suitable one to realize the active noise cancellation. At the end of the thesis, the FIR LMS and Filtered-X LMS structure algorithm will be mentioned and use a digital signal processor to implement noise cancellation to show the realizability of the theory.
Wu, Yenwun, e 吳衍文. "Effect Of Fe3O4 On High Frequency Noise Suppression". Thesis, 2012. http://ndltd.ncl.edu.tw/handle/91493420737740266794.
Testo completo義守大學
電子工程學系
100
This study investigates the effect of Fe3O4 on high frequency noise suppression. The simulator HFSS is employed to investigate the structure and the parameter of magnetic materials and the results were compared with experimental ones. The thickness and conductivity of magnetic films are two important factors in determining the noise suppression. For FR-4 substrate coated with magnetic material Fe3O4, the noise suppression can reach 54% at 10GHz. The result shows that noise suppression can reach 95% at 10GHz for the specimens doping 50wt% conductive silver.
Chen, Yi-Kang, e 陳億剛. "Study on Radio-Frequency Integrated Circuits Noise Suppression". Thesis, 2001. http://ndltd.ncl.edu.tw/handle/70122925255337340698.
Testo completo國防大學中正理工學院
電子工程研究所
89
The purpose of this work is to study substrate noise interfering effect for silicon-based RFICs operation at high frequency. In addition to reduce the influence of substrate noise between digital and analog circuits in RFICs, several substrate noise suppression techniques are considered. In the study, scattering parameters S21 are measured by network analyzer HP8510C to analyze substrate noise forward transmission characteristics. In addition, a commercial device simulation tool ATLAS is used to compare measured results and to predict high-frequency noise-coupling characteristics of various test structures for future applications. Experimental results indicate that grounded P+ guard rings play a role to evacuate noise from substrate to ground, and exhibit very good characteristics in suppressing substrate noise with simple process procedure. The isolation effect of grounded N-well is not as phenomenal as P+ guard rings. Among all test structures, N+ pocket structures with high doping concentration exhibit the strongest noise reduction capability.
Jhou, Shih-Gang, e 周世剛. "Intake Noise Suppression of a High Speed Fan". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/99eny8.
Testo completoWang, Jing-Yi, e 王靖宜. "Intake and Exhaust Noise Suppression Using Destructive Interference". Thesis, 2015. http://ndltd.ncl.edu.tw/handle/h23aj3.
Testo completo國立臺灣海洋大學
機械與機電工程學系
103
This study deals first with the annoying noise generated by the motor driven blades of a portable vacuum cleaner by using the noise interference principle of the Herschel-Quincke tube. Both the theoretical and experimental approaches were utilized for effective noise suppression. In consideration of the size limitation of the vacuum cleaner, the dimensions of the interference silencing device were restrained not to protrude outside the main body. We designed double sets of Herschel-Quincke tube targeting the main noise frequency 725 Hz. Finite element simulation was conducted to examine the 3D sound field characteristics. The sound transmission loss between the inlet and outlet can thus be assessed. The actual designed model was created using a 3D printer. The experiment confirmed the excellent silencing performance. Originally the measured noise of the vacuum cleaner is 81.6 dBA, which is suppressed down to 73.8 dBA, a 7.8 dBA reduction, after applying the interference silencing strategy proposed in this study. The overall noise can be further reduced down to 73 dBA, i.e. an 8.6 dBA reduction, by fine-tuning the exhaust port based on Fluent flow field analysis and experimental observation, while still maintaining the original system performance. Sound intensity measurement technique was utilized to identify the main source noise of the vacuum cleaner for further improvement. The total noise is further suppressed down to 72.5 dBA, a 9.1 dBA reduction. This demonstrates further improvement of the silencing performance. The flow velocity and the pressure measured at the intake showed no significant changes, hence the performance of the original system has not been compromised due to the installation of the noise control device. The interference silencing technique was applied to improve the intake noise of a hand dryer. Originally the measured noise of the hand dryer is 76.1 dBA. After the Herschel-Quincke tube is installed and an appropriate intake port orientation is selected, the total noise is suppressed down to 72.2 dBA, i.e. a 3.9 dBA reduction. Future work can be conducted to further improve the noise suppression performance by increasing the cross sectional area and by smoothing the flow field in the duct.
Hsu, Sheng-Wei, e 許勝為. "Study of Graphene on High Frequency Noise Suppression". Thesis, 2019. http://ndltd.ncl.edu.tw/handle/j5u84x.
Testo completoWu, Jung-Piao, e 吳榮標. "Noise Suppression Techniques for PFC/PWM Combo IC". Thesis, 2016. http://ndltd.ncl.edu.tw/handle/55865008013481924101.
Testo completo國立臺灣科技大學
電子工程系
104
This thesis is proposed to investigate the noise suppression techniques for a PFC/PWM combo IC. When powers on, input current transient noise interferes a 400-W power supply unit’s current sampling and causes the power MOSFET malfunction or damage. Thus, the PFC circuit is modified to suppress the noise according to the measured abnormal signals. After modified, the new design circuit validated at different temperature environments, power sources, and voltage conditions is implemented. As a result of validation, the noise in input current is improved, and the most important of all, the MOSFET of power factor corrector boost circuit would not switch disorder even if the noise exists. The PFC/PWM combo IC can work normally.
Dong-Ming, Ou, e 歐東明. "Image Compression with a Consideration of Noise Suppression". Thesis, 1999. http://ndltd.ncl.edu.tw/handle/73277616657799004575.
Testo completo國立中山大學
電機工程學系
87
In this research , the Kalman Filter is exploited for restoring image against noise corruption . The parameters of the signal model in the Kalman Filter is obtained by our developed segmentation technique which segment the origianl image for computing the image structure of individual region. The image structure are defined to be the linear relationship between pixels with their upper and left neighbors. Image can be very inhomogeneous. However, the image structure may be uniform enough in some image components. By this image texture, individual image constraint equations can be set up for those triple pixel. These equations are the property vectors choosen by us for segmentation decision. Discrepancy between equations are measured by sequential least square method. A recursive method for computing the error is develop in this thesis for simplifying computation. In the field of image processing , Kalman Filter is used for optimal estimation of image corrupted by additive noise. We segment the image by it's local property. By our segmentation technique every region has it's specific image structure, which will be system parameters of Kalman Filter. In this sense , every region has it's suitable Kalman Filter. Therefore the restored image is better in value and in visual effects by our method. Mean time, the number of segmente region for Kalman Filter of the original image is reasonable around 40, thus the original image is compressed to the image structure of the segmented region.