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 1093 for “"Doppler"”.
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Doppler-only synthetic aperture radar
… the imaging process can be performed using high-doppler resolution data. The system requires a simple continuous wave transmitter, and the signal returns are confined to a narrow band. High-doppler resolution data is collected along an isodoppler line for different perspectives of the target. …
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Coherent flow power Doppler imaging
… perfusion. Conventional techniques include color Doppler imaging and power Doppler (PD) imaging. These methods depend on either the measurement of phase change or the detection of the power of backscattered echoes from blood. Both techniques are susceptible to noise. Common noise sources include …
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Monitoring Breathing Using a Doppler Radar
… monitoring the vital signs of inmates in Canada. Doppler radar has been previously investigated as a potential method of vital signs detection and monitoring. This thesis presents an algorithm which uses the baseband output signal received by a Doppler radar to estimate the breathing rate from the …
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Doppler shifts in the KATRIN experiment
… tritium is simulated to study the effects of "Doppler shifts" in the energy of the emitted electrons due to the random thermal motion and fluid flow velocity of the differentially pumped tritium gas. Simulated spectra are presented for three different neutrino masses and the relative effects of …
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Underwater acoustic communication over Doppler spread channels
… of underwater communication channels where the Doppler spread is more severe than the delay spread. An appropriate representation of the linear time- variant channel is introduced, and the wide sense stationary uncorrelated scattering (WSSUS) channel assumption enables characterization in terms …
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Doppler-Windlidar-Messungen der Umströmung einer Windenergieanlage
… 116 m, Nabenhöhe 102 m) mit kohärenten Doppler-Windlidar zu untersuchen. Es wurden zum ersten Mal Messungen an einer Windenergieanlage im Freifeld durchgeführt, die gleichzeitig vor und hinter einer Anlage bis zum Fernnachlauf Daten erfassen können. Durch zwei unterschiedliche Scanmuster …
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Point Doppler velocimetry measurements in circular jets
… have been made to an existing 2-component Point Doppler Velocimetry (PDV) system to improve instrument accuracy and repeatability and to reduce mean velocity offset. Most importantly, the original iodine cells have been replaced by vapor-limited iodine cells that are not influenced by room …
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Techniques for low coherence pulsed Doppler lidar
… a single sideband output containing the baseband Doppler signal shifted up the RF spectrum by a predetermined offset. This is implemented in both electronic and semi-optical configurations. Concept validation experiments have been performed for both techniques. Using the reference beam storage …
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Doppler spread estimation in mobile fading channels
The Doppler spread, or equivalently, the mobile speed, is a measure of the spectral dispersion of a mobile fading channel. Accurate estimation of the mobile speed is important in wireless mobile applications which require such as knowledge of the rate of channel variations. In this dissertation, …
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Power doppler ultrasound for peripheral perfusion imaging
Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2023-12-04 without embargo terms
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Underwater acoustic communication over Doppler spread channels
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1997.
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Doppler channel emulation of high-bandwidth signals
… framework, a module capable of applying Doppler shifting to the input signal was created and tested using DVB-S2 satellite modems. Testing not only verified the functionality of the emulator but also showed that DVB-S2 modems are unequipped to handle the continuous spectral frequency …
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Doppler radar observations of an Oklahoma downburst
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Meteorology and Physical Oceanography, 1983.
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Random phase codes for Doppler weather radars
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1983.
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A doppler electrophoresis instrument for macromolecular characterizations
… electrophoresis method involves the use of the Doppler effect to determine a particle’s characteristics. This thesis is concerned with the design and development of an open geometry Doppler electrophoresis instrument for macromolecular characterization in solution where gel characteristics and …
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Nonlinear Doppler Warp Correction for Acoustic OFDM
… to multipath, frequency selectivity, noise, and Doppler – some of which are more severe. The increased distortion causes many techniques and assumptions made for typical RF communication systems to break down. One of the assumptions that breaks down is that the Doppler effect that the signal …
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Contrast-enhanced Doppler Ultrasound Imaging using Plane Waves
… vascular imaging simultaneously. In ultrasound, Doppler can visualize veins and arteries, but cannot detect the capillary level perfusion. Conversely, microbubble contrast-enhanced ultrasound imaging enables low velocity perfusion to be detected and separated from the tissue echo, but has a …
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