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 18 of 18 for “"power amplification"”.
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Power amplification for piezoelectric actuators in controlled structures
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1995.
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Efficient, low-distortion switch-mode power amplifier for amplitude modulation
… low-level signals are usually not of adequate power to transmit the desired information across a target medium, thus requiring modulation and power amplification. In general, two goals of power amplifier design are low-distortion and high-efficiency. To meet these goals, a unique switch-mode …
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Near junction thermal management of GaN HEMTs via wafer bonding
… (HEMTs) offer excellent performance in power conversion and high frequency power amplification. However, device self-heating limits reliable output power to 1/8th of reported maximums. Device-level thermal management is therefore critical for reliable high power operation. This thesis …
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A new mode of Class D amplification
… there is a need for a more efficient method of power amplification. Class D operation, in which the output transistors are either cut off or saturated and, hence, dissipate very little power, is one method of satisfying this need. This paper presents a study of a new mode of Class D …
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Design of, and initial experiments with, a MIMO plate control testbed
… to eliminate low- and high-frequency noise. The power amplification scheme chosen for the actuators uses low-gain amplifiers (~2.5 V/V) in series with a transformer (24:1) to deliver high voltages (up to 150 V) to the actuators. Low-pass smoothing filters (200 Hz cutoff) were added on the control …
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Electric field engineering in GaN high electron mobility transistors
… (HEMTs) have become the top choice for power amplification at frequencies up to 20 GHz. Great interest currently exists in industry and academia to increase the frequency to mm-wave frequencies. The goal of this thesis has been to identify new solutions to some of the main challenges to …
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Enhanced combined effects in aluminized explosives by an innovative initiation system
… their blast potential and the degree of possible power amplification. In addition to strong bases of technical support, this study provides a plan for experimental demonstration and recommendations for addressing technology issues to more completely exploit the technology for precision strike and …
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Wideband RF Front End Daughterboard Based on the Motorola RFIC
… The reverse is true when we transmit. Amplification is also needed on the receive side to fully utilize the dynamic range of the ADC and power amplification is needed on the transmit side to increase the power output from the DAC for transmission. Analog filtering is also needed to …
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Ultrafast Lasers and Amplifiers based on Yb-doped Gain Materials
The development and advancement of high powered, sub-picosecond laser sources have been crucial to the progression of ultrafast optical studies in the visible and near-infrared spectrum. Highly energetic, broadband pulses can be used to probe the electronic and structural dynamics of some of the …
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Surface and mechanical stress effects in AlGaN/GaN high electron mobility transistors
… RF and microwave communication, as well as high power switching. The first part of this thesis discusses planar AlGaN/GaN transistors. GaN is a piezoelectric material, and changes in mechanical stress result in a change in the charge density which in turn affects the maximum current in AlGaN/GaN …
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Development of Novel Compact Laser Sources for Bio-Medical Applications
… (QD-SOA) are suitable for the broadband pulse power amplification.<br/><br/>Furthermore, master oscillator power amplifier (MOPA) picosecond optical pulse sources using all chirped QD structures were investigated using the MOPA system consisting of two parts, firstly QD-ECMLL and secondly a …
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Gallium nitride high electron mobility transistors in chip scale packaging: evaluation of performance in radio frequency power amplifiers and thermomechanical reliability characterization
… and have been utilized in varying degrees for power amplification purposes at >1 MHz for years. Previously, these devices required costly substrates such as sapphire (Al2O3), limiting applications to little more than aerospace and military. Furthermore, the typical breakdown voltage ratings of …
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Bearing Il/liberal Secondary Witness: Un/disciplined Pedagogies of Response to Testimonial Narratives
… also encompasses neoliberalism, as a form of biopower that differentially distributes vulnerability and protection to populations based on their alignment, or lack thereof, with market thinking. My project thus attends to the discursive and material harms that these commonsense liberal secondary …
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RF techniques for IEEE 802.15.4: circuit design and device modelling
… and ratified network standards suitable for low power applications. After identifying the IEEE 802.15.4 standard (commercially known as ZigBee) as the one of choice, and analysing several front-end architectures on which its transceiver circuitry can be based, an application, the Tyre Pressure …
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Mechanism and applications of elastic actuators
… use of a snapping mechanism in nature to realize power amplification and hence exploits the high work capacity of natural muscles to obtain high accelerations, speeds, and impressive jumping heights. The thesis realized a nature inspired jumping robot through a "dynamic buckling cascade" …
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The dynamics of ultrafast motion in biological and bio-inspired systems: the case study of click beetles
… force-speed trade-offs and amplify mechanical power output. This dissertation introduces a multi-scale analytical and experimental framework to investigate how extreme accelerations are generated in biological systems. I considered click beetles as a case study organism. Click beetles have …
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Biomechanics of Hierarchical Elastic Systems
… the fastest movements in animals are not powered directly by muscle, but instead by elastic energy stored in a spring. By demonstrating that the power required to generate ultrafast movements exceeds the limits of muscle, many studies conclude that energy storage is necessary; but, what …