Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 85 for “"noise source"”.
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Switching mode power supply noise source impedance measurement and EMI filter characterization
… is closely related to the impedance of the noise source. Due to the time-varying nature of the noise source impedance of an offline power supply, the measurement of it cannot be done using conventional impedance measuring methods. Two new methods, the insertion loss method and the signal …
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Aspiration noise during phonation : synthesis, analysis, and pitch-scale modification
… the synthesis and analysis of aspiration noise in synthesized and spoken vowels. Based on the linear source-filter model of speech production, we implement a vowel synthesizer in which the aspiration noise source is temporally modulated by the periodic source waveform. Modulations in the …
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Efficient estimation and mitigation for radio-frequency interference
… electronic device, there are plenty of potential noise sources such as System On Chip (SoC), high speed traces, flexible cables and power converters, etc. Those noise sources can possibly introduce radio frequency interference (RFI) issues. In this dissertation, a transfer function based …
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Frequency Domain Conductive Electromagnetic Interference Modeling and Prediction with Parasitics Extraction for Inverters
… the EMI spectrum directly by decomposing noise sources and their propagation paths. This method not only largely reduces the computational effort, but also provides the insightful information about the critical components of the EMI generation and distribution. The study was first applied …
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Modular Approach for Characterizing and Modeling Conducted EMI Emissions in Power Converters
… and customers. This dissertation studies EMI noise emission characterization and modeling in power converters. A modular-terminal-behavioral (MTB) equivalent EMI noise source modeling approach is proposed. This work is the first to systematically develop a 3-terminal EMI noise source model for …
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Modeling and analysis of source-commutated five-phase diode rectifier systems
… with a project whose goal was to establish the source (and subsequently mitigate) the acoustic noise produced by an automotive alternator. Based upon the finding that torque ripple is a dominant noise source, effort has been focused upon creating a machine-rectifier system that has maximum …
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Synchronization and Signal Enhancement in Nonlinear and Stochastic Systems
… we study the consequences of adding a colored noise source to the classic two-state model of stochastic resonance. We will find that when both white and colored noise sources are present, stochastic resonance will occur as a function of colored noise strength only if the correlation time of the …
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Geometry-Aware Methodology for Coupling Mechanism Analysis and Radiation Mechanism Analysis
… spectrum of digital signals, a variety of noise generators, including microprocessors, liquid crystal displays, digital microphones, high-speed traces, and double-data-rate memory modules, are found in consumer electronics products. Noise generated by digital circuits can couple to the …
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Active control methods for improving the insertion loss of acoustical enclosures
A common method of noise control is the implementation of passive transmission loss enclosures. An acoustical enclosure surrounds a noise source for the purpose of interrupting the noise transmission path. The effectiveness of these enclosures is, however, limited by various drawbacks. These …
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Effect of Boundary-Layer Tripping on Turbulence Generation and Trailing-Edge Noise in Transitional Airfoils
… focus here on attempting to directly predict the noise associated with airframe by considering a single isolated airfoil. Developing an ability to directly predict the radiated noise and how it is generated is a first step for passive or active control of the generated noise. We choose herein a …
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Acoustic optimisation and prediction of sound propagation in turbofan engine ducts
… in this thesis explores the prediction of noise propagation and<br/>radiation in turbofan engine intakes and bypass ducts, and the optimisation of noise attenuation<br/>by using acoustic liners. A commercial FE/IE code ACTRAN/TM is used<br/>within two shell programs; B-induct for bypass …
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Privacy-preserving data publishing and analytics using data cubes
… privacy guarantees for individuals by adding noise to query answers. The first problem is about how to improve the data quality in privacy-preserving data cubes. Our noise-control frameworks choose noise source in a data cube, i.e., an initial subset of cuboids to compute directly from the …
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Machine-Learning based tool to predict Tire Noise using both Tire and Pavement Parameters
Tire-Pavement Interaction Noise (TPIN) becomes the main noise source contributor for passenger vehicles traveling at speeds above 40 kph. Therefore, it represents one of the main contributors to noise environmental pollution in residential areas nearby highways. TPIN has been subject of exhaustive …
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LORE Approach for Phased Array Measurements and Noise Control of Landing Gears
A novel concept in noise control devices for landing gears is presented. These devices consist of elastic membranes creating a fairing around the major noise sources. The purpose of these devices is to reduce wake interactions and to hide components from the flow, thus, reducing the noise emission. …
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A Code Division Multiple Access Communication System for the Low Frequency Band
… our model includes an impulsive (non-Gaussian) noise source to model LF atmospheric noise.
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Computation and control of flow-induced noise behind a circular cylinder using an acoustic analogy approach
… applications, the prediction of both the sound source and its far-field propagation is necessary as required by regulations. Recently, powerful computers and reliable algorithms have allowed the prediction of far-field noise through the use of Computational Fluid Dynamics (CFD) data as …
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Sound from Rough Wall Boundary Layers
… that radiates outside the near wall region. This noise source is often at a lower level than the noise created by edges and bluff body flows, but for applications with large surface area to perimeter ratios at low Mach number, this noise source can have considerable levels. In the first part of …
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Scaling IoT-based noise cancellation to multiple noise sources
… (IoT) sensing techniques with active noise cancellation (ANC) has demonstrated certain benefits over the conventional methods for ANC, including wideband cancellation without blocking the ear and non-causal adaptive filtering. These benefits, however, can only be observed in acoustic …
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Measuring acoustic fields in an optical trap
… is attributed to a large, directional 60 Hz noise source. Analyses of trap stiffness insensitive to this noise are discussed and their results plotted. Knowledge of the trap and the dynamics of trapped objects are used to make measurements of acoustic fields. Cavity modes are identified and …
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URBAN SEISMIC AMBIENT NOISE ANALYSIS: INNOVATIONS AND APPLICATIONS
Seismic ambient noise generated by human activities provides an opportunity to monitor aboveground human activities without intruding on privacy. However, extracting specific signals from noisy seismic noise is challenging. Seismic ambient noise also contains information about the underground …
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