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 44 for “"radio frequencies"”.
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Polarimetric observations at low radio frequencies
… signals to be detected at relatively low radio frequencies. An interferometric polarisation mode has recently become available at the Giant Metrewave Radio Telescope (GMRT). A detailed analysis of the GMRT’s instrumental response is presented. The findings are used to create a polarisation …
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Design and Analysis of N-path Filter for Radio Frequencies
… of wireless communication many communication frequencies have grown increasingly dense. This density requires higher Q-factor to receive only the signal of interest. With the rise of smaller integrated circuits previous solutions used for filtering have become viable again. This paper explores …
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Studies of the Ionised Interstellar Medium at Low Radio Frequencies using LOFAR
… /> As pulsars are mostly observed at radio frequencies, their radiation is affected by interstellar propagation effects like dispersion, which causes a frequency-dependent propagation delay that can vary with time when there is relative motion between the Earth, the pulsar and the gas …
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Exploiting pulsar timing at low radio frequencies: applications to Pulsar Timing Arrays, Interstellar medium and HII regions
Pulsar timing at low radio frequencies offers a powerful way to investigate chromatic propagation effects in the ionised interstellar medium and to refine the modelling of noise processes in Pulsar Timing Array (PTA) analyses. A central element of this thesis is the combination of observations from …
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Numerical modelling and design of wideband electromagnetic structures at radio frequencies: Applications in cosmology and digital communications
… highly accurate and precise understanding of the radiometer instrument. Both the design and analysis of aspects of the REACH dipole radiometer are considered throughout this thesis. While simulation of physical scenarios is to some degree accurate, it is inevitable that uncertainties will arise …
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Bead manipulation to enable electrically controlled wire braiding
… the losses of electronic devices up to MHz frequencies due to the pattern in which the individual wires are braided in the bundle. However, the technology to fabricate Litz wire bundles at higher radio frequencies has not been developed due to current manufacturing limitations. Litz wire …
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An advanced neuromorphic accelerator on FPGA for next-G spectrum sensing
… it’s important to detect and use available radio frequencies effectively. However, current methods face challenges with complexity and noise interference. We’ve developed a new approach using advanced artificial intelligence (AI) based computing techniques to improve efficiency and accuracy …
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Incorporating Wireless Power Transfer in an LED Lighting Application
… power at relatively large distances through radio frequencies in the development of a prototype for a commercial product - a wireless household lamp.</p>
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Auroral arc detection using a COTS spectral photometer for the Auroral Emission Radio Explorer (AERO) CubeSat Mission
… also have interesting emission properties at radio frequencies (RF), specifically in low-frequency and high-frequency bands. The Auroral Emission Radio Observer (AERO) is a 6U CubeSat, equipped with a novel electromagnetic Vector Sensor (VS) antenna. The VS will target auroral emission in a …
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The United States, Radio Architecture, and Global Space, 1933--1951
… investigate the engineering basis for the global radio communications network that succeeded telegraphy and telephony and preceded satellites. Rather than concentrating on the hardware of this network, it focuses on the genealogy of conditions for the less tangible but arguably more significant …
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Design of Power Amplifier Test Signals with a User-Defined Multisine
Cellular radio communication involves wireless transmission and reception of signals at radio frequencies (RF). Base stations house equipment critical to the transmission and reception of signals. Power amplifier (PA) is a crucial element in base station assembly. PAs are expensive, take up space …
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Design and Fabrication of High Frequency Electromagnetic Coil for Magnetic Particle Imaging
… these biomedical applications are seen at low radio-frequencies and higher amplitude fields than ones used for imaging. This work presents a high frequency electromagnetic coil which fulfills operational, safety, and geometric parameters necessary for incorporation in a custom MPI system and …
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Mitigation of Interference From Iridium Satellites by Parametric Estimation and Subtraction
Radio astronomy is the science of observing the universe at radio frequencies. In recent years, radio astronomy has faced a growing interference problem as radio frequency (RF) bandwidth has become an increasingly scarce commodity. Communication systems such as Earth orbiting communication …
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Real-time Adaptive Cancellation of Satellite Interference in Radio Astronomy
Radio astronomy is the science of observing the heavens at radio frequencies, from a few kHz to approximately 300 GHz. In recent years, radio astronomy has faced a growing interference problem as radio frequency (RF) bandwidth has become an increasingly scarce commodity. A programmable real-time …
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X-band digitization systems aspects and filters for MeerKAT radio astronomy receiver
The MeerKAT Radio Telescope is a 64 element antenna array under construction in South Africa. This array will be used to observe radiation from celestial sources at radio frequencies. Once completed, this radio telescope will be the largest and most sensitive radio telescope in the Southern …
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Optimal Access Point Selection and Channel Assignment in IEEE 802.11 Networks
… (APs) in the demand areas and assignment of radio frequencies to each AP. Coverage and capacity are some key issues when placing APs in a demand area. APs need to cover all users. A user is considered covered if the power received from its corresponding AP is greater than a given threshold. …
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High-Performance High-Power Inductor Design for High-Frequency Applications
… magnetic components. This is especially true at Radio Frequencies (RF) of many MHz and above. In the High Frequency (HF, 3-30 MHz) range, coreless (or "air-core") inductors with a typical quality factor (Q) of 200-300 are conventionally used and are often the major contributor to the overall …
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Percolation and nanosecond fluctuators in V2O3 films within the metal-insulator transition
… We measure voltage noise spectra at both low frequencies (up to 100 kHz) and radio frequencies (between 10 MHz and 1 GHz). At low current densities the voltage noise intensity is quadratic in bias current, as expected for resistive fluctuations probed nonperturbatively by the current. The low …
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Ultrasound Data Communications for Ultra-low-power Wake-up in Sensor Nodes
… consumption, compared to conventionally used radio frequencies. An ultra-low-power ultrasonic wake-up receiver IC was designed in a 65-nm CMOS process and has a power consumption of only 4.4 uW. For the proof-of-concept prototype demonstrated in this work, the digital back-end circuits were …
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Long-wavelength imaging and the 4th Amendment
… corners using sound, and through walls using Radio-Frequencies (RF). Then, federal laws and relevant court cases are analyzed to show that the legal precedent is unclear in the context of widely-distributed imaging technologies which can see into a space without entering it. Through this …
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