ITC/USA 2013 Conference Proceedings / The Forty-Ninth Annual International Telemetering Conference and Technical Exhibition / October 21-24, 2013 / Bally's Hotel & Convention Center, Las Vegas, NV / With the characteristics of constant envelope and continuous phase, Continuous Phase Modulation (CPM) signal has higher spectrum efficiency and power efficiency than other modulation forms. A noncoherent demodulation with Viterbi decoding for partial response CPM signals is proposed. Simulation results indicate that the demodulation performance of proper partial response CPM is better than the traditional PCM-FM, which is a typical modulation of full response CPM. And higher spectral efficiency is also obtained by partial response CPM.

Copies of author's previously published articles inserted. / Bibliography: p. 119-129. / xvi, 129, [58] p. : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / This thesis investigated the suitability of liquid crystal spatial light modulators as versatile computer controlled optical elements. The modulation characteristics were determined empirically and experimentally, and their performance as phase modulators tested in the two diverse applications of computer generated holography and phase aberration correction. Commercial liquid crystal panels from a video projector were used, chosen because of low cost, high resolution, computer controlled input, reconfigurability and ready availability. The panels were found to be more suited to amplitude than to phase modulation. Results show that the devices are versatile enough to be adapted to the two very different applications. / Thesis (Ph.D.)--University of Adelaide, Dept. of Physics and Mathematical Physics, 1998

Thesis (Ph.D.)--University of Adelaide, Dept. of Physics and Mathematical Physics, 1998. / Copies of author's previously published articles inserted. Bibliography: p. 119-129.

Thesis (M.S.)--Ohio University, November, 1994. / Title from PDF t.p.

Thesis (M.S.)--Ohio University, August, 1994. / Title from PDF t.p.

Thesis (M.S.)--University of Wyoming, 2007. / Title from PDF title page (viewed on July 28, 2008). Includes bibliographical references (p. 61-62).

Made available in DSpace on 2014-06-11T19:22:31Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-11-18Bitstream added on 2014-06-13T20:29:01Z : No. of bitstreams: 1 barbosa_faa_me_ilha.pdf: 3380301 bytes, checksum: 0446e5c41a7a0d566cf24a9a5a4461f4 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Atuadores piezelétricos flextensionais consistem de uma estrutura metálica flexível acoplada a uma piezocerâmica. A estrutura flexível deve amplificar os pequenos deslocamentos e/ou forças da piezocerâmica, e gerar grandes deslocamentos e/ou forças em diferentes pontos específicos de sua estrutura. Esses dispositivos constituem um mecanismo a estado sólido, sem partes móveis (como pinos ou juntas), sendo que seus deslocamentos/forças estão associados à flexibilidade/rigidez mecânica da estrutura metálica conectada à piezocerâmica. Outra classe de atuadores, mais geral, são os manipuladores multi-atuados, que constituem de uma estrutura multi-flexível acoplada a duas ou mais piezocerâmicas. Novamente, a estrutura multi-flexível atua como um transformador mecânico, amplificando e mudando a direção dos deslocamentos das piezocerâmicas. Tais dispositivos podem apresentar dois ou mais graus de liberdade, como o nano-posicionador XY (com dois graus de liberdade), a micro-garra (quatro graus de liberdade) e outros. Os atuadores piezoelétricos flextensionais e os manipuladores multi-atuados podem ser utilizados em manipulação celular, na manufatura de CIs, em micro-cirurgias, e em muitas outras aplicações. Atualmente, ambos os tipos de atuadores são projetados pela moderna técnica de otimização tipológica, um método computacional que combina algoritmos de otimização com o método de elementos finitos. A interferometria laser constitui uma técnica adequada para caracterizar ambos os tipos de atuadores, permitindo-se a medição de deslocamentos na faixa de poucos nanômetros à vários micrometros. Neste trabalho, utiliza-se um interferômetro de Michelson de baixo custo para medir o fator de calibração e a amplificação de deslocamentos de atuadores piezoelétricos flextensionais, bem como, a relação entre o deslocamento direto e cruzado... / Piezoelectric flextensional actuators consist of a flexible metal frame attached to a piezoceramic. The flexible frames must amplify the small displacements and/or forces at different specific points of their structures. These are solid state type devices, without moving parts (such as pins or joints) and their displacements/forces are associated to the mechanical flexibility/stiffness of the metal structure connected to the piezoceramic. A more generic class of actuators, are the multi-actuated manipulators, which are compose of a multi-flexible structure attached to two or more piezoceramics. Similarly, the multi-flexible structure acts as a mechanical transformer amplifying and changing the direction of the piezoceramic displacements. Such devices may have two or more degrees of freedom, as the XY nano-positioner (with two degrees of freedom), the micro-jaw (four degrees of freedom) and others. Piezoelectric flextensional actuators and multi-actuated manipulators can be used in cell manipulation, manufacture of CIs, micro-surgery and many other applications. Currently, both types of actuators are designed by the modern topology optimization technique, a computational method that combines optimization algorithms with the finite element method. The laser interferometry is a suitable technique to characterize both types of actuators, enabling the measurement of displacements ranging from few nanometers to several micrometers. In this work, it was used a low cost Michelson interferometer to measure the calibration factor and the displacement amplification of flextensional piezoelectric actuators, as well as the relationship between the direct and the coupled displacements in multi-actuated manipulators. A new interferometric method, highly sensitive and suitable to operate under optical narrow band phase modulation is presented. In this method, the actuators are drive by a triangular... (Complete abstract click electronic access below)

Since the introduction of optical fibers in 1960's in communication systems, researchers have encountered many challenges to improve the signal quality at the receiver as well as transmitting the signal as distant as possible. The former was achieved by employing coherent receivers, which let us use M-array modulation formats, such as QPSK, or QAM, and polarization of the signal. The later is accomplished by the advent of optical amplifiers. Optical amplifiers enable us to compensate for the loss occurred within the fiber optic line, without the need for optical-electrical signal conversion. These amplifiers add noise to the line which interacts with the nonlinearity in the fiber line. This interaction causes phase change in the propagating signal called nonlinear phase noise, which degrades the system performance. In this study we will derive an analytical expression for the linear and nonlinear phase noise variance in dispersion unmanaged fiber optic systems, using a first-order perturbation theory. We use numerical examples to depict the proposed system performance in terms of nonlinear phase noise variance. We will conclude that the nonlinear phase variance in a dispersion unmanaged system is much lower than the corresponding noise variance in a dispersion managed system. We will use this concept and will introduce more dispersion in the line by adding fiber brag gratings (FBGs) throughout the fiber link. Through numerical simulations, we will illustrate the improvement we get by adding FBG in each span. We will show that employing FBG improves the system performance for systems working at symbol rates 5 GBaud, which we get the best improvement to less than 20 GBaud, and beyond 20 GBaud there will be no improvement. Nowadays, telecommunication systems based on fiber optics are working at symbol rates around 28 GBaud. We will introduce new models to reduce the nonlinear phase, by splitting digital back propagation (DBP) between transmitter and receiver, and using optical phase conjugation (OPC) in the line. We will prove that the new proposed models lower the phase noise variance significantly, for single pulses. We will also illustrate numerical examples to validate the betterment they provide in terms of Q-factor. / Thesis / Master of Applied Science (MASc)

In this dissertation the performance of a novel variant of a return-to-zero (RZ) modulation format, based on square-wave phase modulation and filtering of a continuous-wave (CW) signal, is investigated and compared with various modulation formats considered in the literature. We call this modulation format continuous-wave square-wave (CWSW). With CWSW an RZ pulse train is generated by phase modulating the CW signal by a periodic square-wave phase function having an amplitude of and frequency of half the bit rate, and then filtering the signal. The filter performs phase-to-amplitude conversion, resulting in an alternate-sign RZ pulse train, which is shown to be resistant to fiber dispersion. The alternate-sign RZ pulse train is then amplitude modulated with the data before the transmission. Alternate signs between adjacent pulses makes this signal format robust to impairments caused by the optical fiber, similar to a conventional alternate-sign RZ signal format. However, the unique property of the CWSW signal format is that individual pulses can induce peak intensity enhancement (PIE), a phenomenon by which the peak of a pulse increases during the initial propagation in the presence of dispersion. The PIE in effect delays the decrease in the pulse peak, which represents the signal level for bit 1. Thus, the eye opening at the receiver is improved. An analytically tractable model is developed to explain the occurrence of the PIE, which cannot be achieved with a conventional pulse shape. The sources of performance degradations for different modulation formats in single-channel 40 Gb/s systems are also discussed in this dissertation. Various transmission system configurations of practical interest are considered and the performance of CWSW is compared with alternative modulation formats. It is found that the CWSW signal format performs significantly better than the other considered modulation formats in systems not employing dispersion compensation and is comparable to the others in dispersion-managed systems. Furthermore, the transmitter configuration of the CWSW signal format is simpler than the other approaches. / Ph. D.

Two new fiber optic magnetostrictive phase modulators and magnetometers using the highly magnetostrictive rare-earth iron compound Tb_xDy_l-xFe₂ are investigated. They demonstrated to have a high sensitivity, dynamic range, minimum field detectability, and a better structural suitability than metallic glasses. For the first sensor, the experimental linear phase shifting coefficient was 1.102 rad/Vp-m with the corresponding phase shift nonnalized to the magnetic field of 0.306 radiO-m. For the second sensor, the experimental linear phase shifting coefficient was 0.5 rad/Vp-m with the corresponding phase shift nonnalized to the magnetic field of 0.136 rad/G-m. A minimum detectable phase shift of better than 1 μrad was obtained, which corresponds to 2 μG/m for a 4 Hz bandwidth and 1 μG/â HZ per meter of fiber interaction length. The projected minimum detectable magnetic field for 30 meters, for the first sensor, is thus seen to be 3pT/â HZ. The experimental results presented have clearly demonstrated the utility of the Terfenol based magnetostrictive fiber optic phase modulator and magnetometer. / Master of Science