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 26 for “"Signal Modulation"”.
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Estimation of signal modulation based on FM to AM transduction
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1997.
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Blind Identification of MIMO Systems: Signal Modulation and Channel Estimation
… the receiver to make an optimal decision on the signal-of-interest, it has to be aware of the type (modulation) of interference as well as how the received signals are affected (channel) by these impediments in order to appropriately mitigate them. This dissertation addresses the blind (unaided) …
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Signal modulation and relative intensity noise properties of transistor laser and nano-cavity VCSEL
… benefits for high speed direct current/voltage modulation capability. We have demonstrated simultaneous E/O data modulation at 20 and 40 Gb/s, and the output signal linearity improvement of both optical and electrical signals of transistor lasers. These provide TL intrinsic advantages for …
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Proton-Implanted Photonic Crystal and Holey Vertical -Cavity Surface -Emitting Lasers
… and increased parasitic resistance, on small-signal modulation bandwidth is studied. Optimized devices exhibit a record 15-GHz small-signal modulation bandwidth.
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Enhanced Modulation Dynamic Performance of Optically-Injected Widely-Tunable Semiconductor Lasers
… theoretical and modelling study of dynamic modulation characteristics of semiconductor wide-wavelength tunable laser diodes (TLDs). The two major goals were to investigate how modulation properties of a TLD depend on the wavelength tuning, and how the modulation performance of a TLD can be …
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Monolithic 1.3 μm InAs/GaAs Quantum Dot Lasers on Silicon: Simulation and Experiment
… dynamics by means of gain switching, small-signal and large-signal modulation. 150 ps short gain-switched pulses, modulation bandwidths of 1.6 GHz to 2.3 GHz, and optical eyes at 1.5 Gb/s are obtained from 2.5 mm long ridge-waveguide lasers grown and fabricated at University College London. …
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Development of light actuated chemical delivery platform on a 2-D array of micropore structure
… Thus, the ability to mimic the natural chemical signal modulation would provide significant contributions to understand the functional signaling pathway of biological cells and develop new prosthetic devices for neurological disorders. In this paper, we demonstrate a light-controlled hydrogel …
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Performance of orthogonal frequency division multiplexing in a high noise, low signal-to-noise ratio environment with co-channel interference
… Multiplexing (OFDM) is fast becoming the signal modulation technique of choice for many commercial and military wireless applications. Its resilience to cochannel interference and bandwidth efficiency make it ideal for many different applications. With its increasing popularity among …
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Electrical parasitics and parameter extraction of photonic crystal vertical-cavity surface-emitting lasers
… of these devices, we perform DC and small signal modulation analysis. Impedance characteristics and electrical parasitics are studied for various photonic crystal designs to understand factors which limit high speed modulation. Photonic crystal designs are found to have low differential …
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Analysis of symmetrical components of harmonics for three phase power systems
… was designed and constructed using the novel signal modulation technique called "+1 and -1" which was developed by the author of this thesis. This instrument was employed to achieve the above objectives.
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Development of ultra-broadband modulators
Optical signal modulation is a cornerstone of communication, allowing the transfer of information by electrically encoding data onto an optical carrier. Modulation with ultra-broadband capability enables the generation of arbitrary waveforms using the electro-optic effect. By separating an incoming …
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Reconfigurable Intelligent Metasurfaces for Wireless Communication and Sensing Applications
… metasurfaces control, metasurface-enabled direct signal modulation, and deep learning-based metasurface design.
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Optical loss and high-speed modulation of vertical-cavity surface-emitting lasers
… interconnects. By increasing the efficiency and modulation speed of these devices, it will be possible to continue to meet a globally increasing demand for bandwidth. After a fundamental discussion of VCSEL design and operation, this thesis focuses on how to improve these microcavity lasers for …
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A digital up-conversion architecture for future high efficiency wireless base stations
… base station. This research is focused on the modulation and up-conversion circuits for generating the SMPA drive signals. The switched (‘on’/‘off’) nature of the amplifier drive signal creates an opportunity for an all-digital solution removing traditional analog components such as the digital …
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Stimulated Brillouin scattering effects and suppression techniques in high power fiber amplifiers
… Brillouin frequencies and the effects of various signal modulation schemes on active ytterbium-doped fiber amplifiers. In addition, temperature effects and temperature differentials within the fibers are predicted and measured, both with passive and active fibers. Brillouin center frequency …
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Simulating the Modulation Response of Vertical -Cavity Surface -Emitting Lasers
… for by MINILASE and their important roles in the modulation response are studied and clarified. First, it is demonstrated that a roll-off in the modulation response is closely associated with the diffusion capacitance caused by vertical carrier leakage. This effect is greatly suppressed by either …
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Interactions of the Striatal Gene Rhes with the Dopaminergic System in Rodents
… Thus, Rhes may play have relevance in dopamine signal modulation. For evaluating the role of Rhes in anxiety, stereotypy and basal motor activity, adult male and female wild-type (WT) mice, Rhes knockout (KO) mice, and mice heterozygous for the KO and WT alleles (Het) were tested. There was no …
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All-optical nonlinear signal processing devices and their applications within fibre-optic communication systems
… holey fibre within a range of nonlinear signal processing devices and an analysis of the performance of these devices from a system context. A range of nonlinear devices based on a holey fibre is demonstrated. Holey fibre has a nonlinearity around 10-100 times greater than conventional …
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Pre-compensation of nonlinear distortion of a silicon microring modulator in short reach systems
… chip size, lower power consumption, and enhanced modulation efficiency, and is potentially preferable for short reach transmission systems. This research focuses on the implementation of an MRM in a high-speed short reach communication system. One issue with Si-MRMs is the nonlinear …
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Metamaterials for High-Efficiency Photonic Integrated Circuits with Multiband Applications in Quantum and Fibre Communications
… the generation and manipulation of optical signals. In particular, the silicon-on-insulator and silicon nitride photonic integration platforms have supported a range of applications due to their compatibility with mature complementary metal-oxide-semiconductor fabrication processes. While …
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