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 299 for “"Signal-to-Noise Ratio (SNR)"”.
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Phase multipath estimation for global positioning system (GPS) using signal-to-noise-ratio (SNR) data
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1997.
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THEORETICAL INVESTIGATION AND PERFORMANCE ASSESSMENT OF REVERSED HYSTERESIS DELTA SIGMA MODULATOR DESIGN
… dissertation studies a unique delta sigma modulator (DSM), known as reversed hysteresis delta sigma modulator (R-HDSM). This modulator is appropriate for ultra-high speed analog-to-digital converters, which can be used for communications and signal processing systems and their applications. …
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A jittered-sampling correction technique for ADCs
In Analogue to Digital Converters (ADCs) jittered sampling raises the noise floor; this leads to a decrease in its Signal to Noise ratio (SNR) and its effective number of bits (ENOB). This research studies a technique that compensate for the effects of sampling with a jittered clock. A thorough …
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Towards improved visual stimulus discrimination in an SSVEP BCI
… (EEG) electrode location and three signal processing methods on the spectral signal to noise ratio (SNR) of Steady State Visual Evoked Potentials (SSVEPs) with a view for use in Brain-Computer Interfaces (BCIs). It was hypothesised that the new spectral baseline processing method …
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On the Capacity of Scalar Gaussian Channels Subject to State Obfuscation
… of the scalar Gaussian fading channel subject to a state-obfuscation constraint imposed in the form of near independence between the channel outputs and the channel coefficients has been studied. By defining the operational capacity as the maximal achievable rate under the state obfuscation …
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Ultraviolet (UV) Laser Implementation, Signal Model, and Measurement Sensitivities in Filtered Rayleigh Scattering for Aerodynamic Flows
… vapor cells as the molecular filter. One method to improve the effective signal-to-noise ratio (SNR), and therefore the performance of an FRS system, is to use shorter wavelengths. This takes advantage of the dependence of the Rayleigh scattering signal on the inverse of the wavelength of the …
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Radiofrequency detector coil performance maps for parallel MRI applications
Parallel MRI techniques allow acceleration of MR imaging beyond traditional speed limits. In parallel MRI, arrays of radiofrequency (RF) detector coil arrays are used to perform some degree of spatial encoding which complements traditional encoding using magnetic field gradients. As the …
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An image quality analysis of ANVIS-6 night vision goggles
This study was undertaken in an effort to relate ANVIS-6 Night Vision Goggle image quality to user performance. The purpose was to determine which of five image quality metrics best related to performance tasks. The image quality metrics examined Modulation Transfer Function Area (MTFA), Integrated …
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Frequency translation method for low frequency variable gain amplification and filtering
This thesis discusses an innovative solution to an industry challenge. A frequency translation method is designed to shift low frequency signals to intermediate frequencies in order to utilize higher-frequency components. This solution, appropriate for applications involving 1-10MHz signals, can …
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Self-supervised multi-contrast MRI denoising
… MRI quality is often compromised by inherent noise, which can hinder both image clarity and analytical accuracy. This thesis presents the "Corruption2Self" (C2S) framework, a self-supervised method for multi-contrast MRI denoising. C2S utilizes self-generated pseudo-labels from noisy data to …
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A sampling jitter tolerant continuous-time pipeline ADC
A sampling jitter tolerant continuous-time (CT) pipeline ADC has been presented in this thesis. In conventional discrete-time (DT) pipeline ADCs, the input is sampled upfront. The improvements in the bandwidth and sampling speed due to CMOS scaling have brought the deleterious effects of sampling …
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Design of a continuous-time bandpass delta-sigma modulator
… continuous-time (CT) bandpass delta-sigma modulator has been designed and simulated in a 65 nm CMOS process. This modulator achieves in simulation 25 MHz signal bandwidth at 250 MHz center frequency with a signal-to- noise ratio (SNR) of 75.5 dB. The modulator samples at 1 GS/s while consuming …
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A 24-channel radio frequency receive array for magnetic resonance imaging of primates at 10.5 T
… offers many advantages and challenges compared to other imaging technologies. The radio frequency (RF) coil is one of the key hardware sub-systems, which drives overall MRI system performance to enable higher resolution imaging and the collection of high fidelity information about organism …
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Methods for Increasing Sensitivity and Throughput of Solid-State NMR Spectroscopy of Pharmaceutical Solids
… (SSNMR) spectroscopy has been demonstrated to be a powerful technique for investigating solid dosage formulations. SSNMR has the ability to determine physical form, molecular structure, and dynamics of a pure or formulated active pharmaceutical ingredient (API). To overcome the major …
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Robust acoustic signal detection and synchronization in a time varying ocean environment
Signal detection and synchronization in the time varying ocean environment is a difficult endeavor. The current common methods include using a linear frequency modulated chirped pulse or maximal length sequence as a detection pulse, then match filtering to that signal. In higher signal to noise …
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Optimal linear array heading in a directional noise field
… thesis discusses a procedure that optimizes the signal-to-noise ratio (SNR) detected by a linear array in a directional ambient noise field. The SNR can be optimized by minimizing the ambient noise detected by the array. For a given target location, each possible heading of the array centers the …
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Determination of the Parameter Limits for Artificial Non-random Microwave Signal Detection
… of small bandwidth (several Hertz) microwave signals makes identification of spectral features difficult; the Doppler individual bandwidth shift can be a factor of hundreds or thousands of times greater than the bandwidth. A computer model supplied by the National Aeronautics and Space …
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An implementation of an AMPS digital base station with adaptive Automatic Gain Control
… problem of choosing an appropriate Analog-to-Digital (ADC) converter. The probability density function of the voltage across a cellular receiving antenna is shown to be dependent on various cellular parameters. These parameters include mobile transmit power, mobile distance from the base …
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Phase optimised general error diffusion for diffractive optical component design
… Diffractive Optical Elements (DOEs) are improved to achieve real time holograms capable of switching at rates of 25frames/second or greater. A Phase Optimised General Error Diffusion (POGED) algorithm optimised for quality and speed of generation of diffractive elements is the main contribution of …
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Spectral estimation with spatio-spectral constraints for magnetic resonance spectroscopic imaging
… spectroscopic imaging (MRSI) is a promising tool to acquire in vivo biochemical information, and spectral estimation (quantification) of MRSI data is an important step towards quantitative studies. Although a large body of work has been done on spectral estimation over the past decades, it …
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