A fully integrated, fast-locking fractional-N frequency synthesizer is proposed and demonstrated in this work. In this design, to eliminate the need for large, inaccurate capacitors and resistors in a loop filter, an analog continuous-time loop filter whose performance is sensitive to process and temperature variations and aging has been replaced with a programmable digital Finite Impulse Response (FIR) filter. In addition, using the adaptive loop gain control proportional to the frequency difference, the frequency-locking time has been reduced. Also, the phase noise and spurs have been reduced by a Multi-stAge noise SHaping (MASH) controlled Fractional Frequency Detector (FFD) that generates a digital output corresponding directly to the frequency difference. The proposed frequency synthesizer provides many benefits in terms of high integration ability, technological robustness, fast locking time, low noise level, and multimode flexibility. To prove performance of the proposed frequency synthesizer, the frequency synthesizers analysis, design, and simulation have been carried out at both the system and the circuit levels. Then, the performance was also verified after fabrication and packaging.

Neste trabalho se apresenta o desenvolvimento de algoritmos hermitianos de integração das equações diferenciais do filtro digital de Butterworth mediante operadores de integração numérica de ordem elevada com passo único. A teoria do filtro de Butterworth é apresentada mediante o emprego da transformada de Fourier. Exemplos de aplicação apresentados através destes algoritmos mostram que os resultados são, como esperado, mais precisos que os resultantes dos métodos usuais presentes na literatura especializada / In this work is presented the development of hermitian algorithm for integration of the Butterworth digital filter’s differential equations by means of high order numerical one step operators. The Butterworth filter’s theory is presented based on the Fourier transform. Numerical examples show that the results of the developed hermitian algorithm are more accurate than the usual methods present in the specialized literature, as expected

Orientador: Amauri Lopes / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-09T08:58:42Z (GMT). No. of bitstreams: 1 Silva_FrancisleiJoseda_M.pdf: 1914501 bytes, checksum: f819de68e8cb02f4b9bc4a46d9787202 (MD5) Previous issue date: 2007 / Resumo: Este trabalho aborda o problema de estimação da direção de chegada (DOA) de ondas planas usando arranjo de sensores. Existem diversos estimadores para DOA relatados na literatura. Dentre os estimadores de alta resolução, se destacam os métodos MODE e MODEX, que possuem como base o estimador de máxima verossimilhança (MLE). Este trabalho apresenta o desenvolvimento dos métodos MODE, MODEX e de uma versão melhorada do MODEX, o método MODEX Modi?ed. Estes dois últimos estimadores produzem várias estimativas candidatas e usam o critério de máxima verossimilhança para selecionar aquelas que representam as melhores estimativas para os ângulos de chegada. Entretanto, para uma relação sinalruído baixa, estes métodos sofrem uma forte degradação na escolha das candidatas. Na busca de reduzir esta degradação, é apresentada uma proposta de ?ltragem nos sinais captados pelos sensores, com o objetivo de melhorar a relação sinalruído. São propostos dois projetos de ?ltro FIR: um por alocação de pólos e zeros, e outro por amostragem em freqüência. Os resultados obtidos mostram que esta proposta de ?ltragem é válida e que se consegue reduzir signi?cativamente a SNR do limiar de desempenho apresentado pelos métodos MODEX e MODEX Modi?ed. / Abstract: This work deals with the estimation of the direction of arrival (DOA) of plane waves using array of sensors. There are various estimators for DOA reported in literature. The MODE and MODEX methods, based on the maximum likelihood criterion, are the best high resolution DOA estimators. This work presents the development of these methods as well as of an improved version of the MODEX, named MODEX Modi?ed. MODEX and MODEX Modi?ed produce some estimates that are candidates for the DOA estimation and use the maximum likelihood criterion to select the best ones. However, for low signaltonoise ratio, the selection process suffers a strong performance degradation. In order to reduce this degradation, this work proposes to ?lter the received signals aiming to improve the signaltonoise ratio. Two FIR ?lters are considered: one composed by poles and zeros and another obtained by sampling in the frequency domain. Simulation results show that this proposal improves signi?cantly the performance of both MODEX and MODEX Modi?ed. / Mestrado / Telecomunicações e Telemática / Mestre em Engenharia Elétrica

A ciência na qual se estuda a deformação de um fluido no qual é aplicada uma tensão de cisalhamento é conhecida como reologia e o equipamento utilizado para a realização dos ensaios é chamado de reômetro. Devido a impraticabilidade de uso de reômetros comerciais, diversos pesquisadores desenvolveram reômetros capazes de analisar suspensões de macropartículas, baseados nos mesmos princípios de funcionamento dos equipamentos já existentes. Em alguns casos, a medição do torque do motor é realizada pela aquisição da tensão, uma vez que esta é proporcional ao torque. Entretanto, para melhor compreensão do resultado e para evitar a possibilidade de conclusões precipitadas, vê-se necessária correta interpretação do sinal elétrico, precisando avaliar qual frequência do sinal é relevante para o ensaio e, também, qual a melhor taxa de amostragem. Além da aquisição, para que o ensaio reológico seja realizado com precisão, é indispensável ótimo controle da taxa ou tensão do motor e uma alternativa é a utilização de um servomotor e um servoconversor. No caso desse ser comercial é essencial saber configurá-lo. Para facilitar o usuário leigo, alguns pesquisadores desenvolveram softwares para controle do equipamento e análise dos dados. Assim, o presente trabalho tem como objetivo propor uma metodologia para compreender o sinal aquisitado de um reômetro servo controlado e desenvolvimento do software de análise para o tratamento dos dados obtidos a partir de ensaios reológicos. Verificou-se a melhor configuração do servocontrolador, a melhor taxa de amostragem, de no mínimo 20 amostras/segundo, e, também, desenvolveu-se um filtro digital passa-baixa do tipo FIR para remover a frequência indesejada. Além disso, foi desenvolvido um software utilizando uma rotina em Matlab e uma interface gráfica do usuário (Graphical User Interface - GUI), para o pós-processamento dos dados para auxiliar o usuário leigo no tratamento e interpretação do resultado, que se mostrou eficaz. / Rheology is the study of the behavior of material in fluid state. Rheometer is the equipment used to perform rheological measurements. Because of the impracticability of commercial rheometer, many researchers have developed rheometer able to analyze macro particles suspension, based on the principle of operation of the existing equipment. In some cases, measurement of the motor torque is performed by acquiring voltage signal, since is proportional to torque. However, for better understanding of the rheological results, it is necessary to understand the electrical signal, evaluating which signal frequency is relevant and what is the best sample rate. In addition, for an accurate rheological testing, it is essential a precise control of the shear rate or shear stress of the motor and a good alternative is the use of a servomotor and a drive. In the case of the drive being commercial, it is essential to know how to configure it. To turn rheometer user-friendly, some researchers have developed software to control the equipment and to analyze data. Thus, this dissertation propose a methodology to understand the electrical signal of a servo controlled rheometer and development of analysis software to process the data obtained from rheological tests. It has been found the best configuration of the servo drive, minimum sampling rate of 20 samples/second, and development of a low pass digital filter to remove unwanted frequency. In addition, was developed a software using a Matlab routine and a Graphical User Interface (GUI) to assist the user in the processing and interpretation of the result.

This Master’s thesis deals with digital decimation filter design for undersampling and filtering of sigma-delta ADC signal. Filter cascade is designed in Matlab according to given requirements and is then described in VHDL language aiming for minimum area. Implemented filter functionality is compared to Matlab-generated reference filters in created verification environment. Finally the design is synthesized in specified technology and verified on gate level.

The doctoral thesis deals with development and design of novel architectures of digital filters for low-power integrated circuits. The main goal was to achieve optimum parameters of digital filters with respect to the chip area, power consumption and operating frequency. The target group of the proposed architectures are application specific integrated circuits designed for signal processing from sensors using delta-sigma modulators. Three novel architectures of digital filters optimized for low-power integrated circuits are presented in the thesis. The thesis provides analysis and comparison of parameters of the new filter architectures with the parameters of architectures generated by Matlab tool. A software tool has been designed and developed for the practical application of the proposed architectures of digital filters. The developed software tool allows generating hardware description of the filters with respect to defined parameters.

It has been aimed to investigate the complexity of discrete-coefficient FIR filters when they are implemented in transposed form and the coefficient redundancy is removed by the n-Dimensional Reduced Adder Graph (RAG-n) approach. Filters with coefficients represented by different quantization schemes have been designed or selected from the literture / their transposed form implemetations after RAG-n process have been compared in terms of complexity. A Genetic Algorithm (GA) based design algorithm has been implemented and used for the design of integer coefficient filters. Algorithms for the realization of filter coefficients in Canonic Signed Digit (CSD) form and realization of n-Dimensional Reduced Adder Graph (RAG-n) have also been implemented. Filter performance is measured as Normalized Peak Ripple Magnitude and implementation complexity as the number of adders used to implement filter coefficients. Number of adders used to implement filter coefficients is calculated by using two different methods: CSD and RAG-n. RAG-n method has been applied to FIR digital filter design methods that don&rsquo / t consider reduction of implementation complexity via RAG-n with transposed direct form filter structure. For implementation complexity, it is concluded that &ldquo / RAG-n algorithm with transposed direct form filter structure&rdquo / provides better results over the &ldquo / CSD, SPT coefficient design followed by transposed direct form filter structure&rdquo / in terms of number of adders used in the implementation.

Submitted by Lucienne Costa (lucienneferreira@ufcg.edu.br) on 2017-12-13T16:54:10Z No. of bitstreams: 1 CÉLIO ANÉSIO DA SILVA - TESE (PPGEE) 2014.pdf: 1651226 bytes, checksum: a70dc4864a551f419c02ff41303eaffc (MD5) / Made available in DSpace on 2017-12-13T16:54:11Z (GMT). No. of bitstreams: 1 CÉLIO ANÉSIO DA SILVA - TESE (PPGEE) 2014.pdf: 1651226 bytes, checksum: a70dc4864a551f419c02ff41303eaffc (MD5) Previous issue date: 2014-05-29 / Capes / Um novo método de obtenção de parâmetros de filtros digitais recursivos (FDR) é apresentado para reduzir o impacto da resposta transitória dos Transformadores de Potencial Capacitivos (TPC) sobre o desempenho dos sistemas de medição, proteção e controle. Assumindo uma topologia predefinida, os parâmetros dos filtros são obtidos a partir da resposta em frequência do TPC de interesse. Diferentemente das técnicas reportadas na literatura, o método se aplica com facilidade a TPC de diferentes classes de tensão e independe das características operacionais do sistema. Para tanto, faz-se necessário conhecer a resposta em frequência do TPC em questão, no espectro de frequência de interesse. A validação do método é realizada através de simulações digitais em tempo real via simulador RTDSTM (Real Time Digital Simulator). As análises são baseadas em dados de sistemas elétricos reais e no funcionamento dinâmico dos filtros através da estimação dos fasores das tensões e estudos de localização de falta. A partir dos resultados obtidos, verifica-se que a presença dos FDR reduz significativamente os erros de medição causados pelos TPC quando submetidos a condições transitórias. Portanto, os FDR surgem como uma forma simples e de baixo custo para melhorar o desempenho e a confiabilidade dos sistemas de medição, proteção e controle. / A new method for obtaining recursive digital filter (FDR) parameters is presented in order to reduce the impact of Coupling Capacitor Voltage Transformer (CCVT) transient response on the performance of the measurement, protection and control systems. Assuming a pre-defined topology, the filter parameters are obtained from the CCVT frequency response of interest. Unlike the techniques reported in the literature, the method applies easily to CCVT of different voltage classes and it does not depend on the operating characteristics of the system, therefore, it is necessary to know the frequency response of the CCVT on the frequency spectrum of interest. The method is validated is through digital simulation using the RTDSTM (Real Time Digital Simulator). The analyzes are based on data obtained from electrical systems in service and on the dynamic performance of the filters by estimating the phasors of voltages and fault location studies. It is shown that the presence of FDR significantly reduces measurement errors caused by CCVT when subjected to transient conditions, therefore, the FDR arises as a simple and low cost alternative to improve the performance and reliability of measurement systems, protection and control.

Orientador: Luís Geraldo Pedroso Meloni / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-16T06:39:32Z (GMT). No. of bitstreams: 1 Okajima_HenriShinichideSouza_M.pdf: 2252019 bytes, checksum: df6b064fa2391bdd5665b43e140c56b1 (MD5) Previous issue date: 2010 / Resumo: Esta dissertação apresenta os resultados obtidos com a pesquisa e implementação de um sistema de demodulação para o receptor de rastreio de um radar de telemedidas. Um radar de telemedidas é responsável pela identificação de um conjunto de medidas realizadas no objeto espacial e enviadas para a antena através de um transponder. A antena de telemedidas deve rastrear o objeto, mantendo-se sempre apontada na direção deste. Para realizar esta função foi utilizada a técnica de monopulso de um canal. Na técnica de monopulso de um canal, cabe ao demodulador digital do receptor executar uma identificação de envoltória e uma demultiplexação temporal que deve permitir encontrar os valores angulares dos erros. A implementação resultou em uma placa de demodulador digital, realizada com um Field Programmable Gate Array (FPGA) da família Cyclone II, e um controlador Freescale, embarcados em uma Placa de Circuito Impresso (PCI) de quatro camadas, projetada para interfacear sinais digitais para controle do sistema de telemedidas e para condicionar os sinais analógicos para posterior processamento. Além de ter interface com placas específicas (por exemplo, CAF - Controle automático de freqüência, CAG - controle automático de ganho, Gerador de Teste, etc), possui também uma interface Controller Area Network (CAN) para comunicação com os módulos de controle de servomecanismos da antena e de interface usuário. Foi desenvolvido também um ambiente de simulação para o demodulador digital em Matlab permitindo verificar a coerência com os resultados esperados e traçar cenários de testes / Abstract: This project presents the results obtained by the research and development of a Demodulation System for a telemetry radar tracking receiver. A telemetry radar system is responsible for identifying a set of measures taken from a spatial artifact and is transmitted by a transponder to its antenna. The telemetry antenna must track the spatial object, maintaining the antenna pointing in the correct direction. To execute this function a single channel monopulse technique is applied. Since the single channel monopulse technique is used, a digital demodulator task is then run for amplitude identification and the de-multiplexing time frame must occur in order to calculate the angle values of errors. This process is explained during the dissertation after the presentation of the main characteristics of radars and some aspects of telemetry systems. The solution is a digital demodulator electronic board, build with an FPGA (Field Programmable Gate Array) from Altera Cyclone II® family, and a Freescale® controller, over a multilayer PCB (Printed Circuit Board) projected to interface with digital signals for the Telemetry Control System and to conditioning analogical signals for processing tasks. The developed board has the CAN (Controller Area Network) interface to communicate with the servomechanism control modules associated with the Antenna and is placed in an armored drawer - to avoid electromagnetic noises - as well as to interact with other specific board functions.A simulation environment was achieved for the digital demodulator in Matlab, allowing the results verification and allowing to establish others testing scenarios / Mestrado / Telecomunicações e Telemática / Mestre em Engenharia Elétrica

This semester project deals with filtering of the images detected by use of NMR obtained by NMR application measurement of nuclear magnetic resonance (NMR). This thesis includes the theory of nuclear magnetic resonance, digital filters, basic digital filter banks structures, theory of Wavelet transformation and description of Signal to Noise Ratio calculation. Basic procedure of the MR signal denoising is summarized in the theoretical part of the thesis. The denoising of the images detected by nuclear magnetic resonance is described. In experimental part filtering methods for images denoising are described, which are implemented in program Matlab. These methods are based on Wavelet transformation, digital filter banks with proper thresholding. Effectiveness of filtering methods designed was verified on 2D NMR images. All of these 2D images were measure on MR tomography in the Institute of Scientific Instruments Academy of Science of the Czech Republic in Brno.