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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
431

Dynamics of amplitude and phase scintillations in a millimetre-wave satellite downlink

Senin, Sergei January 1997 (has links)
No description available.
432

Design and analysis of fixed and adaptive sigma-delta modulators

Yu, Jie January 1992 (has links)
No description available.
433

A direct temporal domain approach for ultrafast optical signal processing and its implementation using planar lightwave circuits /

Xia, Bing, 1972 Nov. 7- January 2006 (has links)
Ultrafast optical signal processing, which shares the same fundamental principles of electrical signal processing, can realize numerous important functionalities required in both academic research and industry. Due to the extremely fast processing speed, all-optical signal processing and pulse shaping have been widely used in ultrafast telecommunication networks, photonically-assisted RFlmicro-meter waveform generation, microscopy, biophotonics, and studies on transient and nonlinear properties of atoms and molecules. In this thesis, we investigate two types of optical spectrally-periodic (SP) filters that can be fabricated on planar lightwave circuits (PLC) to perform pulse repetition rate multiplication (PRRM) and arbitrary optical waveform generation (AOWG). / First, we present a direct temporal domain approach for PRRM using SP filters. We show that the repetition rate of an input pulse train can be multiplied by a factor N using an optical filter with a free spectral range that does not need to be constrained to an integer multiple of N. Furthermore, the amplitude of each individual output pulse can be manipulated separately to form an arbitrary envelope at the output by optimizing the impulse response of the filter. / Next, we use lattice-form Mach-Zehnder interferometers (LF-MZI) to implement the temporal domain approach for PRRM. The simulation results show that PRRM with uniform profiles, binary-code profiles and triangular profiles can be achieved. Three silica based LF-MZIs are designed and fabricated, which incorporate multi-mode interference (MMI) couplers and phase shifters. The experimental results show that 40 GHz pulse trains with a uniform envelope pattern, a binary code pattern "1011" and a binary code pattern "1101" are generated from a 10 GHz input pulse train. / Finally, we investigate 2D ring resonator arrays (RRA) for ultraf ast optical signal processing. We design 2D RRAs to generate a pair of pulse trains with different binary-code patterns simultaneously from a single pulse train at a low repetition rate. We also design 2D RRAs for AOWG using the modified direct temporal domain approach. To demonstrate the approach, we provide numerical examples to illustrate the generation of two very different waveforms (square waveform and triangular waveform) from the same hyperbolic secant input pulse train. This powerful technique based on SP filters can be very useful for ultrafast optical signal processing and pulse shaping.
434

Rapid robust acquisition for burst-mode spread spectrum /

Gossink, D. E. Unknown Date (has links)
Thesis (PhD)--University of South Australia, 1997
435

Coded-waveform design for high speed data transfer over high frequency radio channels /

Gill, Martin Christopher Unknown Date (has links)
Thesis (PhD) -- University of South Australia, 1998.
436

Signal processing techniques for optical fiber networks

Yi, Xingwen January 2007 (has links)
At present, optical fiber transmissions are dominated by intensity modulation and direct detection, which fundamentally limit the signal processing capabilities in optical fiber networks. On the other hand, manipulation of optical phase enables advanced signal processing techniques for various applications. This thesis includes three parts and makes contributions in three research areas in optical fiber networks, by applying optical and electronic signal processing techniques. In the first part of the thesis, optical signal processing is employed to realize a novel all-optical label swapping (AOLS) technique using synchronous phase modulation. This technique is shown to address the forwarding speed bottleneck in optical packet switched networks (OPSN). By exploiting the unique symmetry of phase-shift keying (PSK), for the first time, label erasure and insertion are performed in a single step by a phase modulator without wavelength conversion. We also propose and demonstrate a polarization insensitive phase modulator to address the polarization sensitivity of AOLS. Furthermore, we emulate multi-hop all-optical label swapping in a re-circulating loop to investigate the power penalties from the accumulated phase errors and the timing mismatch. Based on the experimental and analytical results, we show that this technique can save wavelength converters significantly if compared with conventional AOLS techniques requiring dedicate wavelength converters.
437

Coded-waveform design for high speed data transfer over high frequency radio channels /

Gill, Martin Christopher Unknown Date (has links)
Thesis (PhD) -- University of South Australia, 1998.
438

Training signal designs and related signal processing algorithms in broadband wireless communication systems /

Li, Yinghui, January 2007 (has links)
Thesis (Ph.D.)--University of Texas at Dallas, 2007. / Includes vita. Includes bibliographical references (leaves 176-185)
439

Array processing methods for calibrating Inverse Synthetic Aperture Radar and Multiple Pass Synthetic Aperture Radar /

She, Zhishun. January 2000 (has links) (PDF)
Thesis (Ph.D.) -- University of Adelaide, Dept. of Electrical and Electronic Engineering, 2000. / Table of corrections inserted opposite table of contents. Bibliography: p.191-212.
440

Digital processing of shallow seismic refraction data with the refraction convolution section /

Palmer, Derecke. January 2001 (has links)
Thesis (Ph. D.)--University of New South Wales, 2001. / Also available online.

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