Search for dissertations about: "noise aliasing"

Showing result 1 - 5 of 15 swedish dissertations containing the words noise aliasing.

2. 1. Numerical Methods for Aeroacoustic Analysis of Turbomachines

   Author : Daniel Lindblad; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Stability Analysis; Acoustic Analogy; Tonal Noise; Nonreflecting Boundary Conditions; Duct Modes; Turbomachinery; Harmonic Balance; Ffowcs Williams - Hawkings; Time Sampling; Aliasing;

   Abstract : Numerical simulations are important tools for developing new aircraft that can meet future needs. When numerical simulations are used to compute aircraft noise, a two-step procedure is often employed. In the first step, the noise sources are determined using, e.g. READ MORE

4. 2. Generalized Bandpass Sampling Receivers for Software Defined Radio

   Author : Yi-Ran Sun; Svante Signell; Markku K. Renfors; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Radio receivers; Software Defined Radio SDR ; uniform nonuniform sampling; reconstruction; bandpass sampling; noise aliasing; sampling jitter; generalized bandpass sampling; complex signal processing; complex FIR and IIR filter design; Switched-Capacitor SC circuit; Electrical engineering; Elektroteknik;

   Abstract : Based on different sampling theorem, for example classic Shannon’s sampling theorem and Papoulis’ generalized sampling theorem, signals are processed by the sampling devices without loss of information. As an interface between radio receiver front-ends and digital signal processing blocks, sampling devices play a dominant role in digital radio communications. READ MORE

5. 3. The Non-Linear Instantaneous Least Squares Approach to Signal Parameter Estimation

   Author : Jakob Ängeby; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; aliasing; polynomial-phase signals; synthetic aperture radar auto-focusing; non-linear least squares; time-frequency estimation; estimation theory; non-stationary processes; non-uniform sampling;

   Abstract : Estimation of parameters of non-stationary signals observed in noise is a challenging and difficult task, motivated by applications such as radar and mobile tele-communication. Here, a novel method for signal parameter estimation named the Non-linear Instantaneous Least Squares (NILS) approach is presented, which can be applied to linear and non-linear signals, and to both uniformly and non-uniformly sampled data. READ MORE

6. 4. Numerical Methods for Aeroacoustic Analysis of Turbomachinery

   Author : Daniel Lindblad; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Convective Ffowcs Williams - Hawkings Equation; Computational Aeroacoustics; Acoustic Analogy; Von Neumann Stability Analysis; Tonal Noise; CAA; Harmonic Balance Method; Counter Rotating Open Rotor;

   Abstract : Air transportation is today an integral part of many peoples life and it continuously grow to serve more of us in new and ingenious ways. There are however negative sides to this growth as well, such as increased noise around airports and more CO2 emissions, which must be addressed if aviation is to be part of a sustainable future. READ MORE

7. 5. Fast and High-Quality Visibility Determination

   Author : Rasmus Barringer; Institutionen för datavetenskap; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; computer graphics; visibility; anti-aliasing; line sampling; ray tracing; rendering;

   Abstract : Computer generated imagery is vital to the entertainment industry in the production of games and films, for example. It is also increasingly important for visualization in design, architecture, engineering, and medicine, to name a few. Improvements to rendering techniques come from a combination of improved algorithms and more powerful hardware. READ MORE