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Wang, Li. "TDMA digital mobile radio transmission system." Thesis, University of Liverpool, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240335.
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Thom, Gary A., and Edwin Snyder. "Digital Video Telemetry System." International Foundation for Telemetering, 1996. http://hdl.handle.net/10150/608381.
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International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, CaliforniaThe ability to acquire real-time video from flight test platforms is becoming an important requirement in many test programs. Video is often required to give the flight test engineers a view of critical events during a test such as instrumentation performance or weapons separation. Digital video systems are required because they allow encryption of the video information during transmission. This paper describes a Digital Video Telemetry System that uses improved video compression techniques which typically offer at least a 10:1 improvement in image quality over currently used techniques. This improvement is the result of inter-frame coding and motion compensation which other systems do not use. Better quality video at the same bit rate, or the same quality video at a lower bit rate is achieved. The Digital Video Telemetry System also provides for multiplexing the video information with other telemetered data prior to encryption.
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Bilbao, Héctor Uhalte. "DAB Transmission System Simulation." Thesis, Linköping University, Department of Electrical Engineering, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-2595.
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DAB (Digital Audio Broadcasting) is the radio digital system developed as an european standard by the ETSI, EN 300 400, based on the Eureka-147 group works, to improve the performance of the analogue radio systems (AM and FM). The system is based on the OFDM technology which allows DAB to exploit the spectrum frequencies in a better way with a higher quality of sound for mobile receivers specially. The main part of the OFDM system is based on the FFT algorithms to spread the data flow over different orthogonal carriers. The simulation has been developed in SimulinkTMand MatlabTMand the layout designed follows faithfully the standard for the transmission system. The simulation can be reloaded by the user with the information presented in this thesis. Thus, this work can be continued to complete the DAB whole system simulation. The results obtained running this simulation show the main DAB system characteristics.
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Yong, Yoke Chuang. "Receive channel architecture and transmission system for digital array radar." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2005. http://library.nps.navy.mil/uhtbin/hyperion/05Dec%5FYong.pdf.
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Thesis (M.S. in Combat Systems Technology)--Naval Postgraduate School, December 2005.Thesis Advisor(s): David C. Jenn, Donald L. Walters. Includes bibliographical references (p.75-76). Also available online.
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Chung, Edward C. "The implementation of a personal computer-based digital facsimile information distribution system." Ohio : Ohio University, 1991. http://www.ohiolink.edu/etd/view.cgi?ohiou1183661772.
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Carvalho, Silvio Renato Messias de 1960. "Contribuições para melhoria da confiabilidade de redes de frequência única em sistemas de transmissão de TV digital." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/261224.
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Orientador: Yuzo IanoTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação
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Resumo: Este trabalho apresenta uma nova proposta para o conceito de redes de frequência única, SFN. Redes de radiodifusão em SFN são assim chamadas por utilizarem um único canal de transmissão ou uma única frequência. Nesta proposta os transmissores de uma rede SFN são conectados formando uma rede real que por sua vez se interliga a pontos receptores chamados de pontos monitores estrategicamente localizados dentro da área de cobertura. Uma rede de radiodifusão que possa se adaptar dinamicamente às variações das condições do canal é útil porque aumenta a confiabilidade da rede. A modificação proposta apresenta vantagens para as emissoras de televisão que possuam redes de retransmissão destinadas a ampliar sua cobertura em uma área regional com várias cidades obtendo um ambiente de rede muito mais controlado e seguro. O conceito também pode ser aplicado a gap-fillers e repetidores de mesmo canal on channel. O trabalho apresenta simulações de cobertura para mostrar as variações do canal e a resposta da rede
Abstract: This paper presents a new approach for the concept of single frequency networks, SFN. SFN broadcasting networks are so named because they use a single transmission channel or a single frequency. In this proposal the transmitters in a SFN network are connected together to form a real network that in turn connects to receptor sites called 'monitor point' strategically located within the coverage area. A broadcasting network that can dynamically adapt to changing channel conditions is useful because it increases network reliability. The proposed modification has advantages for television stations that have relay stations aiming to expand its coverage in a regional area with a network more controlled and secure. The concept can also be applied to gap- fillers and repeaters on channel. This work presents simulations of coverage to show variations in channel and network response
Doutorado
Telecomunicações e Telemática
Doutor em Engenharia Elétrica
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Moura, Luis Miguel da Silva Carvalho de. "Circuit techniques for very high speed digital optical transmission : timing extraction sub-system." Thesis, Bangor University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262231.
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Malan, Jacques de Villiers. "Microwave data transmission by means of an optimal bandwidth multichannel QPSK system." Thesis, Stellenbosch : Stellenbosch University, 2004. http://hdl.handle.net/10019.1/50022.
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Thesis (MScEng)--Stellenbosch University, 2004.Full text to be digitised and attached to bibliographic record.
ENGLISH ABSTRACT: The increase in the complexity and functionality of new satellites leads to a growing demand for a digital communication system operating at a much higher bit rate than before. The main purpose of this thesis is to address precisely this problem. The theory as well as a practical high speed system are custom-developed. The goal of this thesis is not to reinvent the wheel, but to use off-the-shelf products as far as possible. This system demonstrates that a very high data rate is not out of reach for a developer with limited funds. The secondary goal is to understand the operation of this communication system. The emphasis is on the inaccuracies in the system. A design tool is created to act as a vehicle for understanding the influence of a single variable on the performance of the entire system.
AFRIKAANSE OPSOMMING: Die toename in die kompleksiteit en funksionaliteit van nuwe satelliete lei tot die groeiende behoefte aan 'n digitale kommunikasiestelsel wat teen "n heelwat hoër bis spoed funksioneer. Die hoofdoel van hierdie tesis is om juis hierdie probleem aan te spreek. Die teorie en 'n praktiese hoëspoed stelsel is ontwikkel. Die doel van die tesis is nie om die wiel te herontdek nie maar om sover moontlik bestaande produkte in die ontwerp van die stelsel te gebruik. Die stelsel demonstreer dat 'n hoëspoed datatempo nie buite die bereik van 'n ontwikkelaar met beperkte fondse is nie. 'n Verdere doelwit is om die funksionering van die kommunikasie stelsel te begryp. Klem is gelê op die onakkuraathede in die kommunikasiestelsel. Ontwikkeling sagteware is geskep as "n metode om die invloed van "n enkele veranderlike op die werkverrigting van die stelsel as geheel te begryp.
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Ahdab, Ahmad Talal. "Practical and theoretical evaluation of a transmission system using the CPFSK digital modulation scheme." Thesis, University of Ottawa (Canada), 1986. http://hdl.handle.net/10393/5015.
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Xu, Tianhua. "Digital Dispersion Equalization and Carrier Phase Estimation in 112-Gbit/s Coherent Optical Fiber Transmission System." Licentiate thesis, KTH, Optik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-34034.
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Coherent detection employing multilevel modulation format has become one of the most promising technologies for next generation high speed transmission system due to the high power and spectral efficiencies. With the powerful digital signal processing (DSP), coherent optical receivers allow the significant equalization of chromatic dispersion (CD), polarization mode dispersion (PMD), phase noise (PN) and nonlinear effects in the electrical domain. Recently, the realizations of these DSP algorithms for mitigating the channel distortions in the transmission system are the most attractive investigations. The CD equalization can be performed by the digital filters developed in the time and the frequency domain, which can suppress the fiber dispersion effectively. The PMD compensation is usually performed in the time domain with the adaptive least mean square (LMS) and constant modulus algorithms (CMA) equalization. Feed-forward and feed-back carrier phase estimation algorithms are employed to mitigate the phase noise from the transmitter and local oscillator lasers. The fiber nonlinearities are compensated by using the digital backward propagation methods based on solving the nolinear Schrodinger (NLS) equation and the Manakov equation. In this dissertation, we present a comparative analysis of three digital filters for chromatic dispersion compensation, an analytical evaluation of carrier phase estimation with digital equalization enhanced phase noise and a brief discussion for PMD adaptive equalization. To implement these investigations, a 112-Gbit/s non-return-to-zero polarization division multiplexed quadrature phase shift keying (NRZ-PDM-QPSK) coherent transmission system is realized in the VPI simulation platform. With the coherent transmission system, these CD equalizers have been compared by evaluating their applicability for different fiber lengths, their usability for dispersion perturbations and their computational complexity. Meanwhile, the bit-error-rate (BER) floor in carrier phase estimation using a one-tap normalized LMS filter is evaluated analytically, and the numerical results are compared to a differential QPSK detection system.QC 20110629
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Bailey, Brian Douglas. "Design of a video measurement system." Thesis, Virginia Polytechnic Institute and State University, 1988. http://hdl.handle.net/10919/80071.
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Tsang, Yui Ming. "Optimal resource allocation algorithm with QoS and fairness supported for SDMA OFDM system /." View abstract or full-text, 2004. http://library.ust.hk/cgi/db/thesis.pl?ELEC%202004%20TSANGY.
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Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2004.Includes bibliographical references (leaves 63-66). Also available in electronic version. Access restricted to campus users.
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Moura, Tiago Sousa. "High efficiency energy harvesting system from D-TV spectrum." Master's thesis, Universidade de Aveiro, 2015. http://hdl.handle.net/10773/18868.
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Mestrado em Engenharia Eletrónica e TelecomunicaçõesA recolha de energia do meio ambiente para alimentar dispositivos como forma de os tornar auto-sustentáveis tem vindo cada vez mais a suscitar interesse. Por outro lado, o crescimento contínuo do espectro resultante das telecomunicações constitui uma grande oportunidade para a colheita de energia. Assim sendo, neste trabalho e proposto um sistema altamente e ciente de recolha de energia de rádio-frequência que utiliza o sinal da televisão digital (D-TV) portuguesa e que converte-o em tenso que poder a ser reaproveitada. De forma a ser vantajoso, o sistema e otimizado para operar a baixos níveis de potência. Assim, o presente trabalho pretende também fornecer orientações para o correto desenvolvimento do sistema de colheita de energia para baixa potência de entrada, contribuindo para o desenvolvimento de projetos futuros. O sistema e dividido numa antena recetora e num retificador. Para o retificador são propostas três soluções distintas: um díodo série, um díodo paralelo e um duplicador de tensão. A eficiência obtida e semelhante para as três configurações - cerca de 54% para um sinal de entrada sinusoidal com um nível de potência de -10.5 dBm. Medições com o multiplicador de tensão e o sinal real da D-TV como entrada mostraram uma eficiência de 63% para o mesmo nível de potência. Relativamente à antena, e proposta uma patch com slots e com um elemento parasita que utiliza como substrato dielétrico FR-4. Esta configuração resulta da necessidade de melhorar a largura de banda da microstrip simples. Medições mostraram um aumento da largura de banda em cerca de 4 vezes quando em comparação com uma patch simples.
Collect energy from the surroundings is being biased to power-up devices in order to turn them self-sustainable. On the other hand, the spectrum resultant from the telecommunications tends to progressively increase and becomes wide-reaching, constituting an enormous opportunity to energy harvesting. Thus, in this work a high e ciency radio-frequency energy harvesting system is proposed that takes uses of the Portuguese Digital Television (D-TV) signal to obtain Direct Current (DC) power. To be useful, the system is optimized to operate at low power conditions. So, this work also aims to provide reliable guidelines in the design of energy harvesting systems with low-input power. The system is divided into an antenna and a recti er. For the recti er, three di erent solutions are presented: a single-series diode, a singleshunt diode and a voltage doubler con guration. The e ciency is similar for the three recti ers { around 54% with a sine-wave excitation and -10.5 dBm input power. Field measurements with the voltage doubler has proven 63% e ciency for the same input power. As receiver antenna is proposed a slotted patch with a stacked parasitic based on FR-4 substrate. This con guration results from the need to improve the bandwidth of the basic microstrip patch. Measurements have proven and enhancement around 4 times in comparison with a basic patch.
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Lange, Werner R., and Martin Ravensbergen. "TIME REFERENCE SYSTEM OF THE ESO VERY LARGE TELESCOPE." International Foundation for Telemetering, 1995. http://hdl.handle.net/10150/608540.
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International Telemetering Conference Proceedings / October 30-November 02, 1995 / Riviera Hotel, Las Vegas, NevadaThe necessity of supplying precise time information in large telemetry ground stations and astronomical observatories is very similar. Therefore the way of solving this problem as it is done in the Very Large Telescope of the European Southern Observatory can be easily adopted to telemetry stations and ranges, especially when fiber optics are used. The European Southern Observatory (ESO) is building a new observatory in Chile for the Very Large Telescope (VLT). This VLT consists of 4 telescopes, each of them has a primary mirror diameter of 8 meters. the control architecture is based on workstations and VMEbus computers. The VMEbus computers are distributed over the whole building and are using real time operating system. Since the availability of the Global Positioning System (GPS) the generation of highly accurate timing signals on remote locations without the use of expensive Cesium standards does not create problems any more. However, distribution of a timing signal to many computer with high accuracy is an issue. The accuracy of the commonly used IRIG B-code is not adequate if the requirements are in the 10 microseconds range. This paper presents the design of a timing system that is adopted to the VLT. An overview of the requirements of the Time Reference System (TRS) is given. These requirements have been defined on the basis of experiences with the timing system of the ESO NTT telescope. The hardware units are described. These are a Central Time Standard, a Time Distribution System and a VME Time Interface Module. The distribution is based on fiber optic transmission, using a simple digital modulation that outperforms the analog IRIG B modulation. The Time Interface Module in the computer does not only perform the timing signal decoding but contains also user-programmable timers that are synchronously clocked from the time source. Presently all units of the TRS have been tested and the series production of the distribution and the Time Interface Modules are in progress.
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Lu, Chun, Yihong Yan, and Jian Song. "An Application of Sync Time Division Multiplexing in Telemetry System." International Foundation for Telemetering, 2013. http://hdl.handle.net/10150/579685.
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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, NVHigh speed real-time data transportation is most important for telemetry systems, especially for large-scale distributed systems. This paper introduces a STDM (Sync Time Division Multiplexing) network structure for data transportation between devices in telemetry systems. The data in these systems is transported through virtual channels between devices. In addition, a proper frame format is designed based on PCM format to meet the needs of synchronization and real-time transportation in large-scale distributed telemetry systems.
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Silva, Edson Porto da 1988. "Transmissão óptica com recepção coerente e alta eficiência espectral aplicando sequências de pulsos RZ e pré-filtragem optica em canais limitados em banda." [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/259687.
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Orientadores: Michel Zamboni Rached, Julio Cesar Rodrigues Fernandes de OliveiraDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação
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Resumo: O Resumo poderá ser visualizado no texto completo da tese digital
Abstract: The complete Abstract is available with the full electronic document.
Mestrado
Telecomunicações e Telemática
Mestre em Engenharia Elétrica
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Shibahara, Kohki. "Advanced Signal Processing for Fiber-Optic Communication Systems Scaling Capacity Beyond 100 Tb/s." Kyoto University, 2017. http://hdl.handle.net/2433/227663.
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Nteka, Makhetsi Flora. "Development and assessment of reduced order power system models." Thesis, Cape Peninsula University of Technology, 2013. http://hdl.handle.net/20.500.11838/1088.
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Thesis submitted in fulfilment of the requirements for the degree
Master of Technology: Electrical Engineering
in the Faculty of Engineering
at the Cape Peninsula University of Technology
2013The demand for electrical energy has kept on increasing, thus causing power systems to be more complex and bringing the challenging problems of electrical energy generation, transmission, stability, as well as storage to be examined more thoroughly. With the advent of high-speed computation and the desire to analyze increasingly complex behaviour in power systems, simulation techniques are gaining importance and prevalence. Nevertheless, while simulations of large, interconnected complex power systems are feasible, they remain time-consuming. Moreover, the models and parameters used in simulations are uncertain, due to measurement uncertainty, the need to represent a complex behaviour with low-order models, and the inherent changing nature of the power system. This research explores the use of a model reduction technique and the applications of a Real-Time Digital Simulator (RTDS) to reduce the uncertainty in large-scale complex power system models. The main goal of the research is to develop a reduced order model and to investigate the applications of the RTDS simulator in reduction of large, interconnected power systems models. The first stage of the study is to build and simulate the full model of the power system using the DigSILENT and RTDS simulators. The second phase is to apply model reduction technique to the full model and to determine the parameters in the reduced-order model as well as how the process of reduction increases this model uncertainty. In the third phase the results of the model reduction technique are compared based on the results of the original model - IEEE standard benchmark models has been used. The RTDS was used for comparative purposes. The thesis investigations use a particular model reduction technique as Coherency based Method. Though the method ideas are applicable more generally, a concrete demonstration of its principles is instructive and necessary. Further, while this particular technique is not relevant to every system, it does apply to a broad class of systems and illustrates the salient features of the proposed methodology. The results of the thesis can be used in the development of reduced models of complex power systems, simulation in real-time during power system operation, education at universities, and research. Keywords: IEEE benchmark models, reduced models, Coherency based Method, DigSILENT, RTDS, model uncertainty, power system stability
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Cneazovici, Fabian. "Implementation of a Visible Light Communication System on 32-bit ARM Microcontrollers." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021.
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Nel presente lavoro di tesi l'obietto è stato l'implementazione di un sistema di Visible Light Communication (VLC) sfruttando dei microcontrollori ARM a 32 bit, più precisamente i STM32 Nucleo-L432KC Board di STMicroelectronics. L'implementazione è consistita nello sviluppo software dei blocchi di codifica/decodifica, modulazione/demodulazione e di sincronizzazione che vanno a costituire il trasmettitore e il ricevitore. VLC è una tecnologia di comunicazione wireless che sfrutta la luce visibile, invece delle onde a frequenze radio, come mezzo per la trasmissione dell'informazione. Quindi, trasmettitore e ricevitore devono essere dotati rispettivamente di una fonte di luce e di un fotosensore, in sostituzione alle antenne. Per quanto riguarda il trasmettitore, la fonte di luce è sempre a base di LED, in quanto quest’ultimi presentano enormi vantaggi rispetto alle tradizionali fonti di luce a incandescenza e fluorescenza, tra cui l'elevata velocità di commutazione tra due livelli diversi di intensità luminosa che consente la trasmissione di dati ad elevate velocità. Per il ricevitore invece, il fotosensore può essere un fotorilevatore, cioè un fotodiodo, oppure un sensore d’immagine, cioè il sensore della fotocamera. Nel caso del presente progetto, in trasmissione è stato usato un solo LED mentre in ricezione un fotodiodo. Il sistema VLC implementato, a causa di problemi legati ai timer, è affetto da problemi di sincronizzazione che potrebbero essere risolti con l'introduzione di algoritmi di recupero del sincronismo di simbolo. Tale problematica viene meglio descritta nell'elaborato di tesi, come vengono anche fornite una più dettagliata descrizione della tecnologia VLC e dell'implementazione del sistema. Inoltre, vengono anche suggerite, oltre all'introduzione dell'algoritmo di recupero del sincronismo di simbolo, anche altri possibili sviluppi futuri di tale progetto.
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Malkoc, Veysi. "Sequential alignment and position verification system for functional proton radiosurgery." CSUSB ScholarWorks, 2004. https://scholarworks.lib.csusb.edu/etd-project/2535.
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The purpose of this project is to improve the existing version of the Sequential Alignment and Position Verification System (SAPVS) for functional proton radiosurgery and to evaluate its performance after improvement .
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COHEN, ROBERT. "Modelisation, filtrage et controle de processus stochastiques." Paris, ENST, 1987. http://www.theses.fr/1987ENST0015.
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Presentation d'une formule de filtrage pour un modele de filtrage ou une observation supplementaire a l'observation continue est disponible a des temps d'arrets mesurables par rapport a la filtration de l'observation consideree dans son ensemble. On donne une solution au probleme de controle stochastique dans les systemes lineaires avec un cout terminal. Une etude sur l'existence et l'unicite de la solution forte a l'equation du filtre est prouvee
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Alston, Katherine Yvette. "A heuristic on the rearrangeability of shuffle-exchange networks." CSUSB ScholarWorks, 2004. https://scholarworks.lib.csusb.edu/etd-project/2521.
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The algorithms which control network routing are specific to the network because the algorithms are designed to take advantage of that network's topology. The "goodness" of a network includes such criteria as a simple routing algorithm and a simple routing algorithm would increase the use of the shuffle-exchange network.
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Caldwell, Niall James. "Digital Displacement hydrostatic transmission systems." Thesis, University of Edinburgh, 2007. http://hdl.handle.net/1842/27735.
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Digital Displacement pumps and motors are a new type of hydraulic machine, in which fluid commutation and displacement control are achieved by solenoid actuated valves under the command of a microprocessor, rather than mechanical means. The thesis is that radial piston machines, built according to this principle, offer energy efficiency and control advantages over variable stroke axial piston pumps, when applied to hydrostatic vehicle transmissions. Experimental results on the efficiency of prototypes are analysed and compared to published results from swashplate machines, showing an improvement in energy efficiency. Loss models are proposed and compared with experiment. A Digital Displacement motor suitable for propelling a vehicle is described and the design and development of the mechanics, electro-magnetics and embedded software are described. Experimental results are also presented, illustrating the performance of a demonstrator vehicle driven by the motor, in particular demonstrating the closed-loop regulation of vehicle speed using motor displacement control. A demonstrator vehicle is described which features a hydrostatic transmission using both a Digital Displacement pump and an axial piston motor. Experimental results of pump performance are presented with specific focus on vehicle propel. A control technique is described which increases the sensitivity of the pump at low speeds. Results are presented of tests on the prototype transmission system, focussing on the time-domain system dynamics. A computer simulation model of the vehicle is presented and results compared to experiment.
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Hachfi, Fakhreddine Mohamed. "Future of asynchronous transfer mode networking." CSUSB ScholarWorks, 2004. https://scholarworks.lib.csusb.edu/etd-project/2639.
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The growth of Asynchronous Transfer Mode (ATM) was considered to be the ideal carrier of the high bandwidth applications like video on demand and multimedia e-learning. ATM emerged commercially in the beginning of the 1990's. It was designed to provide a different quality of service at a speed up 100 Gbps for both real time and non real time application. The turn of the 90's saw a variety of technologies being developed. This project analyzes these technologies, compares them to the Asynchronous Transfer Mode and assesses the future of ATM.
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Airoldi, Douglas. "Sistema de comunicação de dados pela rede elétrica, de baixo custo, aplicado a uma rede de medidores individuais de energia elétrica residencial = concepção do circuito, protótipo e testes." [s.n.], 2011. http://repositorio.unicamp.br/jspui/handle/REPOSIP/259334.
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Orientador: José Antonio Siqueira DiasDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação
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Resumo: Este trabalho é parte de um projeto de pesquisa e desenvolvimento de uma rede de mini-medidores de energia, de baixíssimo custo, que se comunica com uma central, que armazena todas as informações relativas ao consumo de energia elétrica, de cada um dos pontos de consumo de uma residência. Ao fim de um período, fornece ao consumidor condições de analisar a distribuição do seu gasto com energia elétrica por ponto medido. Neste trabalho foi desenvolvido um sistema de comunicação de dados pela rede elétrica, também conhecida como Power Line Communication (PLC)). O hardware, de baixo custo, é composto por microcontrolador e um modem integrado que utiliza o processo Amplitude Shift Keying (ASK), com taxas de comunicação entre 600 e 1200 bps (bits por segundo). O firmware criado é composto de um protocolo que realiza a comunicação half-duplex entre duas estações de medição, permitindo ao transmissor da informação, saber se a mesma foi recebida com integridade
Abstract: This work is part of a research project and develops a network of mini-power meters, very low cost, which communicate with a central, which stores all information relating to the consumption of electricity, each of the points consumption of a residence. At one time, it gives the consumer the ability to analyze the distribution of its spending power by the measured point. We have developed a communication system for data grid, also known as Power Line Communication (PLC). The hardware, low cost, consists of microcontroller and an integrated modem that uses the process Amplitude Shift Keying (ASK), with communication rates between 600 and 1200 bps (bits per second). The firmware is created consisting of a protocol that performs half-duplex communication between two measuring stations, allowing the transmitter of information, whether it was received with integrity
Mestrado
Eletrônica, Microeletrônica e Optoeletrônica
Mestre em Engenharia Elétrica
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Wu, Kuang-Tsan. "On spectrally efficient digital transmission systems." Thesis, University of Ottawa (Canada), 1986. http://hdl.handle.net/10393/5408.
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Axelberg, Peter. "On Tracing Flicker Sources and Classification of Voltage Disturbances." Doctoral thesis, Högskolan i Borås, Institutionen Ingenjörshögskolan, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-3416.
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Developments in measurement technology, communication and data storage have resulted in measurement systems that produce large amount of data. Together with the long existing need for characterizing the performance of the power system this has resulted in demand for automatic and efficient information-extraction methods. The objective of the research work presented in this thesis was therefore to develop new robust methods that extract additional information from voltage and current measurements in power systems. This work has contributed to two specific areas of interest.The first part of the work has been the development of a measurement method that gives information how voltage flicker propagates (with respect to a monitoring point) and how to trace a flicker source. As part of this work the quantity of flicker power has been defined and integrated in a perceptionally relevant measurement method. The method has been validated by theoretical analysis, by simulations, and by two field tests (at low-voltage and at 130-kV level) with results that matched the theory. The conclusion of this part of the work is that flicker power can be used for efficient tracing of a flicker source and to determine how flicker propagates.The second part of the work has been the development of a voltage disturbance classification system based on the statistical learning theory-based Support Vector Machine method. The classification system shows always high classification accuracy when training data and test data originate from the same source. High classification accuracy is also obtained when training data originate from one power network and test data from another. The classification system shows, however, lower performance when training data is synthetic and test data originate from real power networks. It was concluded that it is possible to develop a classification system based on the Support Vector Machine method with “global settings” that can be used at any location without the need to retrain. The conclusion is that the proposed classification system works well and shows sufficiently high classification accuracy when trained on data that originate from real disturbances. However, more research activities are needed in order to generate synthetic data that have statistical characteristics close enough to real disturbances to replace actual recordings as training data.
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RAMIREZ, MISAEL ALBERTO RABANAL. "ON-OFF DIGITAL TRANSMISSION IN OPTICAL SYSTEMS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1989. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=9248@1.
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CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOUma análise de desempenho da transmissão digital, com modulação tipo ON-OFF através de fibras óticas foi feita incluindo todos os estágios do circuito. A partir desta análise foi desenvolvido um método para o dimensionamento e o cálculo da qualidade destes sistemas óticos digitais. O método permite calcular o comprimento máximo da fibra ótica em função das características dos diversos circuitos que compõem o enlace, taxa de transmissão e objetivo de qualidade.
It was made an analysis of performance of digital transmission with modulation ON-OFF through optical fiber including all circuit phases. From this analysis it was developed a method to the dimensioning and the quality calculation of these digital optical systems. This method allows to determine the maximum length of optical fiber, since the characteristics of all enlace circuits, of date rate and the quality objective are known.
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Guiomar, Fernando Pedro Pereira. "Digital nonlinear equalization for optical transmission systems." Doctoral thesis, Universidade de Aveiro, 2015. http://hdl.handle.net/10773/15977.
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Doutoramento em Engenharia EletrotécnicaThis thesis focuses on digital equalization of nonlinear fiber impairments for coherent optical transmission systems. Building from well-known physical models of signal propagation in single-mode optical fibers, novel nonlinear equalization techniques are proposed, numerically assessed and experimentally demonstrated. The structure of the proposed algorithms is strongly driven by the optimization of the performance versus complexity tradeoff, envisioning the near-future practical application in commercial real-time transceivers. The work is initially focused on the mitigation of intra-channel nonlinear impairments relying on the concept of digital backpropagation (DBP) associated with Volterra-based filtering. After a comprehensive analysis of the third-order Volterra kernel, a set of critical simplifications are identified, culminating in the development of reduced complexity nonlinear equalization algorithms formulated both in time and frequency domains. The implementation complexity of the proposed techniques is analytically described in terms of computational effort and processing latency, by determining the number of real multiplications per processed sample and the number of serial multiplications, respectively. The equalization performance is numerically and experimentally assessed through bit error rate (BER) measurements. Finally, the problem of inter-channel nonlinear compensation is addressed within the context of 400 Gb/s (400G) superchannels for long-haul and ultra-long-haul transmission. Different superchannel configurations and nonlinear equalization strategies are experimentally assessed, demonstrating that inter-subcarrier nonlinear equalization can provide an enhanced signal reach while requiring only marginal added complexity.
A presente tese foca-se no tema da equalização digital de distorções não lineares da fibra em sistemas coerentes de transmissão ótica. Tirando partido de modelos físicos bem conhecidos para a propagação de sinal em fibras óticas mono-modo, novas técnicas de equalização não linear são propostas, testadas numericamente e validadas por demonstração experimental. A estrutura dos algoritmos propostos é fortemente condicionada pela otimização do compromisso entre complexidade e desempenho, tendo em conta a sua futura implementação prática em transcetores comerciais operando em tempo-real. O trabalho desenvolvido foca-se inicialmente na mitigação das distorções não lineares intra-canal, aplicando o conceito de propagação digital inversa realizado através de filtros de Volterra. Após uma análise sistemática do núcleo de Volterra de terceira ordem, é identificado um conjunto de simplificações críticas, culminando no desenvolvimento de algoritmos de equalização não linear de baixa complexidade, formulados no domínio do tempo e frequência. A complexidade de implementação das técnicas propostas e analiticamente descrita em termos de esforço computacional e latência de processamento, através da determinação do número de multiplicações reais por amostra e do número de multiplicações realizadas em série, respetivamente. O desempenho da equalização e avaliado recorrendo a simulação numérica e validação experimental através da medição da taxa de erros. Por fim, a questão da compensação não linear inter-canal é abordada no contexto da propagação de supercanais 400G para sistemas de transmissão metro e longa distância. Nesse âmbito são experimentalmente testadas diferentes configurações de supercanal e estratégias de equalização não linear, demonstrando assim que a implementação de equalização inter-subportadora permite estender consideravelmente o alcance, requerendo apenas um esforço computacional ligeiramente superior.
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Han, Yu. "Optimization of Modulation Constrained Digital Transmission Systems." Thesis, Université d'Ottawa / University of Ottawa, 2018. http://hdl.handle.net/10393/37097.
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The regular waterfilling(WF) policy maximizes the mutual information of parallel channels, when the inputs are Gaussian. However, Gaussian input is ideal, which does not exist in reality. Discrete constellations are usually used instead, such as $ M $-PAM and $ M $-QAM. As a result, the mercury/waterfilling (MWF) policy is introduced, which is a generalization of the regular WF. The MWF applies to inputs with arbitrary distributions, while the regular WF only applies to Gaussian inputs. The MWF-based optimal power allocation (OPA) is presented, for which an algorithm called the internal/external bisection method is introduced.
The constellation-constrained capacity is discussed in the thesis, where explicit expressions are presented. The expression contains an integral, which does not have a closed-form solution. However, it can be evaluated via the Monte Carlo method. An approximation of the constellation-constrained capacity based on the sphere packing method is introduced, whose OPA is a convex optimization problem. The CVX was used initially, but it did not generate satisfactory results. Therefore, the bisection method is used instead.
Capacities of the MWF and its sphere packing approximation are evaluated for various cases, and compared with each other. It turns out the sphere packing approximation has similar performances to the MWF, which validates the approximation. Unlike the MWF, the sphere packing approximation does not suffer from the loss of precision due to the structure of MMSE functions, which demonstrates its robustness.
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Rizk, Ziad. "Digital data transmission over an HF channel." Thesis, Loughborough University, 1996. https://dspace.lboro.ac.uk/2134/7232.
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The thesis is concerned with detection, estimation techniques and a method of the adaptive adjustment of the equaliser, for use in a 4800bit/sec synchronous digital transmission system operating over a voice-band time-varying HF channel. Two main impairments are additive Gaussian noise and inter-symbol interference (ISI), which can be very severe at times. All techniques considered here are algorithms or processes that operate on sequences of sample values. Modern digital modems normally operate in this way, and the techniques described are of direct application to practical systems, and could be implemented using the new technology of high speed real-time digital signal processing (DSP). The performance of the various systems that employ the above techniques are obtained using the computer simulated model of three types of HF channels. The ionospheric propagation medium, the characteristics of HF channel and the signal distortion introduced by the channel are first described. The thesis then presents a suitable base-band model of the HF channel for computer simulation of quadrature amplitude modulation systems. A suitable method for the adjustment of the receiver is described next. This method is suitable both for the adjustment of a conventional decision feedback equaliser (DFE), and also for the adjustment of a linear feedforward filter that is employed ahead of a near-maximum likelihood (NML) detector. This method uses a minimum phase (root-finding) algorithm (MPA) to convert the channel response from being non-minimum phase to at least approximately minimum phase. The results of computer simulation tests of this algorithm are then presented over different types of HF channel models. The results demonstrate the algorithm's capability to make the channel response minimum (or near-minimum) phase. Various NML detectors, derived from the Viterbi detector, are discussed. Each detector is here preceded by an adaptive linear filter that is adjusted adaptively using an MPA. The performance of these detectors is compared with the conventional DFE, whose tap-gains are adjusted adaptively using an MPA, and the detector which gives the best compromise between performance and complexity is selected for combined receivers. These results are obtained using perfect estimation of the channel response. The estimation techniques studied in this thesis include both new and conventional estiniators, which are based on the least- mean-square (LMS) algorithm or recursive least-square(RLS) algorithm. The estimator provides an estimate of the sampled impulse response (SIR) of the channel, necessary for the NML detector or MPA. The performances of these estimators are compared using computer simulation tests. The results also demonstrate that the simpler LMS algorithm with adaptive step size gives a comparable level of accuracy with the more complex RLS algorithm. Finally the most promising of the detectors and estimators are connected with an adaptive equaliser, using an MPA, to form a new combined receiver. The details of the combined system structure with its computational complexity are given. Extensive computer simulation tests have been carried out on the different arrangements of the combined system including DFE, when all the functions of detection, estimation and MPA are present, in order to find the most cost effective system in terms of performance and complexity. A considerable reduction in the equipment complexity can be achieved by allowing a long period between successive adjustment of the adaptive filter and estimator.
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Wong, S. W. "Frequency hopping data transmission at high frequency." Thesis, University of Manchester, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317262.
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Chandra, Mariswamy Girish. "A new binary transmission scheme for improving the performance of digital transmission systems." Thesis, Imperial College London, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.409394.
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Fu, Deng Yuan. "ADAPTIVE DIGITAL IMAGE DATA COMPRESSION BY RECURSIVE IDPCM." Thesis, The University of Arizona, 1985. http://hdl.handle.net/10150/275350.
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Muthukkumarasamy, Vallipuram. "Data assisted equalisation for high speed digital transmission systems." Thesis, University of Cambridge, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334181.
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MOREIRA, WAYNE DE SOUSA. "EFECT OF LINEAR DISTORTION IN DIGITAL TRANSMISSSION SYSTEMS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1991. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=9257@1.
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CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOO trabalho analisa o desempenho de sistemas de transmissão digital com modulação de amplitude em quadratura (QAM), considerando o efeito de distorções na função de transferência do canal de transmissão. Assumindo formas polinomiais, senoidais e exponenciais para a função de transferência do canal, são calculados analiticamente o valor médio quadrático e o valor de pico da interferência entre símbolos (IES) em um sistema QAM com filtros de transmissão e recepção com espectros em raiz quadrada de cosseno levantado. As expressões obtidas são então utilizadas para calcular, aproximadamente, a probabilidade de erro e avaliar o efeito das distorções no desempenho dos sistemas, com aplicações ilustrativas a sistemas QAM- 16 e QAM-64. É dada uma atenção especial à função de transferência associada ao modelo de 2 raios, geralmente utilizada para representar o efeito de desvanecimento seletivo em sistemas radio digitais. Com os resultados obtidos neste caso e a suposição de que a IES se comporta como uma variável Gaussiana, propõe-se um método baseado em expressões analíticas relativamente simples para determinar, com precisão razoável, a assinatura de sistemas radio digitais.
The performance of digital transmission systems with quadrature amplitude modulation (QAM) is analised considering the effect of linear distortions in the channel transfer function. Assuming polinomial, sinusoidal and exponential forms for the channel transfer function, the mean square value and the peak value of the intersymbol interference (ISI) are analitically determined in a QAM system with square-root raised cosine transmit and receive filters. The obtained analytic expressions are then used to approximate the error probability and to evaluate the distortion effect in the system performance with particular application to some 16-QAM and 64-QAM systems. Special attention is given to the 2-Ray Model transfer function, generally used to represent selective fading in digital radio systems. Assuming that the ISI behaves as a Gaussian variable and using relatively simple analytic expressions, a method is proposed to determine the Signature of a digital radio system.
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Butler, Richard. "Aspects of burst errors in digital telecommunications transmission systems." Thesis, Robert Gordon University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386407.
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Oliveira, Inês do Vale Marques. "Digital chromatic dispersion equalization in optical coherent transmission systems." Master's thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/21735.
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Mestrado em Engenharia Eletrónica e TelecomunicaçõesA crescente procura de largura de banda tem obrigado a área de comunicações óticas a explorar diferentes soluções, de forma a evitar a ”crise de capacidade” [1]. O investigadores têm trabalhado no sentido de atingir o equilíbrio entre os vários compromissos, repensando a forma como o sinal ótico é enviado e recebido, para que a perda de informação seja mínima ao longo do canal de propagação. No inıcio desta década, começaram a ser adotados formatos de modulação avançada, os quais apresentam elevada eficiência espetral, bem como deteção coerente, que permite extrair a informação da amplitude e da fase do campo ótico. Estas técnicas são complementadas pelo pós-processamento digital de sinal, que é atualmente muito importante na mitigação das distorções do sinal e imperfeiçoes do recetor. As distorções do sinal podem ser causadas, por exemplo, pela dispersão cromática na fibra. Esta dissertação engloba o estudo e simulação de um sistema de transmissão coerente PM-QPSK, bloco-a-bloco, fazendo uma abordagem detalhada dos conceitos supramencionados. O sistema foi então simulado na presença de dispersão cromática e de ruído, alternada e simultaneamente. Os resultados mostram que o sinal recebido apresenta uma distribuição quase Gaussiana em todos os casos. Com vista a recuperar o sinal transmitido, e no caso em que só se considerou o efeito da dispersão cromática, aplicou-se um filtro linear de resposta impulsional inversa à da fibra, conseguindo assim uma equalização digital perfeita do sinal recebido. Também foi implementado um filtro adaptado no receptor para minimizar o efeito do ruído, obtendo não uma equalização perfeita, mas ótima.
The crescent demand on high bandwidth has been compelling the optical communications area to explore di erent solutions, in order to avoid the \capacity crunch" of the optical bres [1]. Researchers have been working towards reaching the best tradeo s balance, rethinking the way as the optical signal is sent and received, so the loss of information is minimum throughout the propagation channel. Advanced modulation formats became adopted in the beginning of this decade, presenting high spectral e ciency, as well as coherent detection, which allows extracting information from the amplitude and phase of the optical eld. These techniques are complemented by post-digital signal processing, which is nowadays very important at mitigating signal distortions and receiver imperfections. Those impairments result, for instance, of the chromatic dispersion at the bre. This dissertation covers the study and simulation of a PM-QPSK transmission system, block-by-block, approaching in detail the concepts mentioned above. The system was then simulated with chromatic dispersion and with noise, alternately and simultaneously. The results show that the received signal presents an almost Gaussian distribution in every case. In order to retrieve the transmitted signal, and in the case that only chromatic dispersion's e ect was considered, a linear lter was applied with an inverse impulse response of the bre, achieving such a perfect digital equalization of the received signal. A matched lter was also implemented in the receptor to minimize the noise e ect, obtaining not a perfect equalization, but an optimal one.
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McGleenon, Patrick. "Modelling the management behaviour of synchronous digital hierarchy transmission networks." Thesis, Queen's University Belfast, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361221.
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Ameen, Siddeeq Yousif. "The adaptive adjustment of digital data receivers using pre-detection filter." Thesis, Loughborough University, 1990. https://dspace.lboro.ac.uk/2134/27569.
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This thesis is concerned with the adaptive adjustment of digital data receivers employed m synchronous serial data transmission systems that use quadrature amplitude modulation The receiver employs a pre-detection filter that forms the first part of a decision feedback equalizer or else is used ahead of a near maximum-likelihood detector. The filter is ideally adjusted such that the sampled impulse response of the channel and filter is minimum phase.
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Haddad, Nicholas. "Transmission of digital images using data-flow architecture." Ohio : Ohio University, 1985. http://www.ohiolink.edu/etd/view.cgi?ohiou1184007755.
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Liang, Feng. "Performance enhancement of digital relays for transmission line distance protection /." Internet access available to MUN users only, 2003. http://collections.mun.ca/u?/theses,153681.
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Rachinger, Christoph [Verfasser]. "Power Efficient Digital Transmission for MIMO Systems using Spherical Codes : Leistungseffiziente digitale Übertragung für Mehrantennensysteme mittels sphärischer Codes / Christoph Rachinger." Aachen : Shaker, 2018. http://d-nb.info/1162794305/34.
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Efstathiou, Dimitrios. "Fully digital feed-forward synchronisation techniques for burst mode transmission systems." Thesis, King's College London (University of London), 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.338731.
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Autry, Chris Brian. "Minimization of jitter in SDH/SONET networks via an all-digital desynchronizer." Diss., Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/15412.
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Wang, Dongmei. "Video coding and transmission for multimedia communications using a 3-D graphics model." Diss., Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/13836.
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Lodge, Nicolas Kim. "Interpolative coding methods for the digital transmission of conventional and high definition television." Thesis, Heriot-Watt University, 1993. http://hdl.handle.net/10399/1442.
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Khire, Sourabh Mohan. "Time-sensitive communication of digital images, with applications in telepathology." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/29761.
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Thesis (M. S.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2010.Committee Chair: Jayant, Nikil; Committee Member: Anderson, David; Committee Member: Lee, Chin-Hui. Part of the SMARTech Electronic Thesis and Dissertation Collection.
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Revelant, Ivan L. "Restoration of images degraded by systems of random impulse response." Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/26731.
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The problem of restoring an image distorted by a system consisting of a stochastic impulse response in conjuction with additive noise is investigated. The method of constrained least squares is extended to this problem, and leads to the development of a new technique based on the minimization of a weighted error function. Results obtained using the new method are compared with those obtained by constrained least squares, and by the Wiener filter and approximations thereof.
It is found that the new technique, "Weighted Least Squares", gives superior results if the noise in the impulse response is comparable to or greater than the additive noise.Applied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate
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Gautier, Luiz Reinaldo. "Localizadores digitais de faltas para linhas de transmissão de alta tensão." Universidade de São Paulo, 1996. http://www.teses.usp.br/teses/disponiveis/18/18133/tde-25012018-120255/.
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Localizadores de faltas são dispositivos designados para determinar a localização do ponto de incidência de faltas em linhas de transmissão dos sistemas elétricos de potência. Esta localização possibilita uma restauração mais rápida da operação de um sistema elétrico, contribuindo assim para um alto grau de continuidade no fornecimento de energia. Este trabalho apresenta um estudo comparativo entre duas abordagens distintas para localização digital de faltas. Os métodos se distinguem quanto à natureza dos dados de entrada. Um dos métodos utiliza dados disponíveis apenas em um único terminal, enquanto que o outro, utiliza dados provenientes dos dois terminais da linha de transmissão. As teorias fundamentais de ambas as técnicas são estudadas e simulações computacionais das mesmas são extensivamente testadas utilizando-se dados provenientes de uma simulação das linhas de transmissão sob falta.Fault locators are devices designed to pinpoint the location of the fault on transmission lines of electric power systems. This location allows a fast restoration of the power system operation, contributing to a high level of continuity on power delivery. This work shows a comparative study between two digital fault locator approaches. The methods differ on the nature of input data. One of the methods uses data available from only one end, while the other uses data from the both ends of the transmission line. The fundamental theories of the two techniques will be studied, and computacional simulations are extensively tested with data obtained from simulation of faulted transmission lines.