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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.
11

Testovací systém pro zařízení V-mux / The V-mux test system

Morávek, Patrik January 2008 (has links)
An optical network technology is the network technology that meets given requirements for a fast and reliable long-distance information transmission. Optical fibres can offer undoubted features where other communication technologies are near their limits or stand in front of insurmountable problems. The intensive research of last years is focused on optical transmission features utilization in the optimal way. Especially an optical signal processing in active network devices without a need for electrical conversation is a topic of high interest. V-Mux is an optical network device that accomplishes above mentioned requirements for modern optical network devices. It is a device that multiplexes and drops an optical signal in its native light form into or from optical fibre. Basic micro electro-mechanical components, which the V-Mux is built from, are high end precise devices. The whole complex V-Mux has to meet strict rules and specifications as the components itself. That is why a control system has to be included in the production process to keep quality and right functionality. This diploma thesis is focused on a development of the testing system that will help in the automated control procedure in the V-Mux production. A brief introduction to optical network technologies and a description of the GPIB bus form a first part of the thesis. The next part focuses on the V-Mux itself and the proposal of the test station with its component description. The last part deals with a developing of the software for the V-Mux testboard and a user application that will be used for the test system initialization.
12

Investigation of High-Nonlinearity Glass Fibers for Potential Applications in Ultrafast Nonlinear Fiber Devices

Kim, Jong-Kook 23 August 2005 (has links)
Nonlinear fiber devices have been attracting considerable attention in recent years, due to their inherent ultrafast response time and potential applications in optical communication systems. They usually require long fibers to generate sufficient nonlinear phase shifts, since nonlinearities of conventional silica-core silica-clad fibers are too low. These long devices, however, cause the serious problems of pulse walk-off, pulse broadening, and polarization fluctuation which are major limiting factors for response time, switching bandwidth, and maximum transmittable bit-rate. Therefore, short device length is indispensable for achieving ultrafast switching and higher bit-rate data transmission. To shorten the required device length, fiber nonlinearities should be increased. In this dissertation, as a way of increasing fiber nonlinearities, high-nonlinearity materials of Litharge, Bismite, Tellurite, and Chalcogenide glasses have been considered. Although they have high nonlinearities, they also have high group-velocity dispersion and high losses deteriorating the performance of nonlinear fiber devices seriously. The aim of this work is to investigate how these high-nonlinearity glasses affect the performance of nonlinear fiber devices, taking into consideration both the advantages and disadvantages. To achieve it, the critical properties of various nonlinear fiber devices constructed with the different types of high-nonlinearity glasses and different types of fibers have been evaluated. It turned out that the required device lengths of nonlinear fiber devices constructed with the high-nonlinearity glasses were significantly reduced and high group-velocity dispersions and losses could not be major problems due to the extremely short device length. As a result, it would be possible to suppress the problems of pulse walk-off, pulse broadening, and polarization fluctuation in nonlinear fiber devices by introducing high-nonlinearity glasses, thus enabling ultrafast switching and higher bit-rate data transmission. Furthermore, in this dissertation, a new scheme of wavelength-division demultiplexing based on the optical Kerr effect has been proposed for the first time. The new scheme can turn the disadvantage of the extremely high group-velocity dispersion of high-nonlinearity glasses into an advantage of wavelength-division demultiplexing. Finally, it now would be possible to greatly increase maximum transmittable bit-rate in optical communication systems by simultaneously demultiplexing optical time-division-multiplexed signals and wavelength-division-multiplexed signals with an optical Kerr effect-based demultiplexer. / Ph. D.
13

Analysis and Development of Fixed and Variable Waveband MUX/DEMUX Utilizing AWG Routing Functions

Kakehashi, Shoji, Hasegawa, Hiroshi, Sato, Ken-ichi, Moriwaki, Osamu, Kamei, Shin 01 January 2009 (has links)
No description available.
14

Módulo IP de um Demultiplexador para o Subsistema Fluxo de Transporte- MPEG-2-Aderente ao Sistema Brasileiro de TV Digital

Medeiros, Leonardo 04 March 2010 (has links)
Made available in DSpace on 2015-05-14T12:36:55Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 2141642 bytes, checksum: c8c8d7a9c0ea40b4a1ad5f10de888b74 (MD5) Previous issue date: 2010-03-04 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In the Brazilian scenario, the development of hardware components through computational methodologies and tools, available at affordable costs to education and research centers have make it feasible to design blocks and integrated circuit modules up to intellectual property IP level, focusing strategic areas of industry, specially those dedicated to the components for the Brazilian Digital Television System (SBTVD). This work deals with the architectural proposal development and validation for the Transport Stream MPEG-2 TS Subsystem of SBTVD transport stream demultiplexer from its specification and high-level modeling to its technology mapping implementation. As specific results, the structural and functional requirements of Transport Stream Subsystem MPEG-2 TS are detailed, the development of a software model for the demultiplexer and of an environment containing MPEG-2 TS flows that can validate the compliance with the SBTVD specification of models, an RTL-level MPEG-2 TS demultiplexer IP conceptual proof implementation and validation and its prototyping with technology mapping for FPGA and an ASIC design kit , are also presented. / No cenário brasileiro, o desenvolvimento de componentes de hardware através de metodologias e ferramentas computacionais, disponibilizados a custos acessíveis a centros de ensino e pesquisa tornou factível a possibilidade de se projetar até o nível de propriedade intelectual IP, blocos e módulos de circuitos integrados para atender áreas estratégicas da indústria, em especial aquelas voltadas aos componentes de produtos aderentes ao Sistema Brasileiro de Televisão Digital (SBTVD). Este trabalho trata o desenvolvimento e validação de uma proposta arquitetural para o Subsistema de Fluxo de Transporte MPEG-2 TS demultiplexador de fluxo de transporte do SBTVD, desde sua especificação e modelagem em alto-nível, até sua implementação no nível de mapeamento tecnológico. Também estão apresentados resultados específicos como o detalhamento dos requisitos estruturais e funcionais do Subsistema de Fluxo de Transporte MPEG-2 TS, o desenvolvimento de um modelo em software para o demultiplexador e de um ambiente contendo fluxos MPEG-2 TS capazes de validar a conformidade dos modelos com a especificação do SBTVD, a implementação e validação de uma prova de conceito para um demultiplexador MPEG-2 TS no nível RTL e sua prototipagem com mapeamento tecnológico para FPGA e para um design kit de ASIC.
15

Měření přijímače pro pozemní digitální televizi DVB-T / Measurements of the DVB-T Digital Television Receiver

Kobza, Jaromír January 2010 (has links)
This thesis is focused on a receiver for digital television broadcasting set-top box, mainly on its features, parameters and measurement. The important point of this work is the possibility to analyze and visualize the parallel transport stream in the same time and the solution of this problem. The principle of tuner and its measuring is deeply discussed. The text is supported with oscilloscope screenshots in particular parts of decoding stream. The set-top box is modified for laboratory measurement purpose and the transport stream output is added. An example laboratory exercise was created as a part of this work.
16

MPEG Z/Alpha and high-resolution MPEG / MPEG Z/Alpha och högupplösande MPEG-video

Ziegler, Gernot January 2003 (has links)
<p>The progression of technical development has yielded practicable camera systems for the acquisition of so called depth maps, images with depth information. </p><p>Images and movies with depth information open the door for new types of applications in the area of computer graphics and vision. That implies that they will need to be processed in all increasing volumes.</p><p>Increased depth image processing puts forth the demand for a standardized data format for the exchange of image data with depth information, both still and animated. Software to convert acquired depth data to such videoformats is highly necessary. </p><p>This diploma thesis sheds light on many of the issues that come with this new task group. It spans from data acquisition over readily available software for the data encoding to possible future applications. </p><p>Further, a software architecture fulfilling all of the mentioned demands is presented. </p><p>The encoder is comprised of a collection of UNIX programs that generate MPEG Z/Alpha, an MPEG2 based video format. MPEG Z/Alpha contains beside MPEG2's standard data streams one extra data stream to store image depth information (and transparency). </p><p>The decoder suite, called TexMPEG, is a C library for the in-memory decompression of MPEG Z/Alpha. Much effort has been put into video decoder parallelization, and TexMPEG is now capable of decoding multiple video streams, not only in parallel internally, but also with inherent frame synchronization between parallely decoded MPEG videos.</p>
17

Estudo do desempenho do Multiplexador/Demultiplexador add/dropbaseado na configuraÃÃo do InterferÃmetro de Michelson de fibras Ãpticas para aplicaÃÃes em sistemas OTDMA e OCDMA / Study the performance of the multiplexer/demultiplexer add/drop based on the Michelson interferometer configuration for fiber for applications in optical systems OTDMA and OCDMA

Antonio Francisco Gomes Furtado Filho 02 March 2012 (has links)
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Neste trabalho, alÃm dos capÃtulos que envolvem a teoria e definiÃÃes, foi basicamente divido em trÃs estudos: Primeiro (capÃtulo 4), apresentamos uma investigaÃÃo numÃrica do desempenho de um filtro passa-banda totalmente Ãptico composto por um acoplador direcional duplo seguido de duas grades de Bragg simetricamente iguais gravadas nos seus braÃos de saÃda. Esta configuraÃÃo caracteriza um InterferÃmetro de Michelson com caracterÃsticas de um filtro add/drop. As caracterÃsticas de transmissÃo (T), taxa de extinÃÃo (XR) e âcrosstalkâ (XT) foram estudadas a partir da aplicaÃÃo de um sinal CW (onda contÃnua) na entrada do dispositivo. A teoria de modos acoplados e o mÃtodo de Runge Kutta de 4a ordem foram aplicados, respectivamente para resolver as equaÃÃes diferenciais acopladas. Este à o primeiro estudo feito considerando a nÃo linearidade do acoplador e a linearidade das grades de Bragg. O dispositivo apresenta um comportamento altamente nÃo-linear em funÃÃo do defasamento entre as amplitudes dos feixes refletidos e em funÃÃo da potÃncia de entrada. Num segundo momento (capÃtulo 5) apresentamos a propagaÃÃo e chaveamento de pulsos ultracurto (~2ps) usando um interferÃmetro de Michelson de Fibras Ãpticas. Neste estudo o desempenho do interferÃmetro à estudado como uma funÃÃo das caracterÃsticas nÃo lineares do acoplador e das grades de Bragg. Os estudos numÃricos foram feitos a partir das equaÃÃes de modos acoplados resolvidas usando o mÃtodo de Runge-Kutta de 4 ordem. As caracterÃsticas de chaveamento do pulso foram analisadas em funÃÃo da potÃncia de entrada e do defasamento aplicado em uma das grades de Bragg. As caracterÃsticas de transmissÃo (T), coeficiente de ExtinÃÃo (XR), âcrosstalkâ (XT), fator de compressÃo (FC). Utilizamos trÃs valores de potÃncia de entrada: abaixo da potÃncia critica (P0=1W), igual a potÃncia crÃtica (P0=1,73W) e acima da potÃncia crÃtica (P0=1,95W). AtravÃs deste estudo, pode-se verificar que a transmissÃo, taxa de extinÃÃo, âcrosstalkâ e fator de compressÃo dependem da potÃncia da bombeio inserida no dispositivo e da defasagem aplicada. O interferÃmetro de Michelson em fibras implementa componente de grande importÃncia para aplicaÃÃes em redes Ãpticas, como os demultiplexadores add/drop. Este dispositivo tem atraÃdo bastante interesse no campo das telecomunicaÃÃes devido a sua alta capacidade de taxas de transmissÃo. Num terceiro momento foi apresentado um estudo de simulaÃÃo numÃrica do desempenho da codificaÃÃo e decodificaÃÃo de pulsos Ãpticos curtos (ps) em sistemas OCDMA (Optical Code Division Multiple Access â acesso VIII mÃltiplo por divisÃo de cÃdigo no domÃnio Ãptico) baseado em FBG (Fiber Bragg Grating â grade de Bragg em fibra Ãptica) onde os cÃdigos sÃo inseridos atravÃs de saltos discretos na fase Ãptica (Â&#960;). Para geraÃÃo de pulsos codificados foram utilizados cÃdigos de Gold obtidos analiticamente. Analisamos como a inserÃÃo de cÃdigos adicionais afetam a autocorrelaÃÃo e correlaÃÃo cruzada. O interferÃmetro de Michelson inicialmente estudado no capÃtulo 4 foi utilizado para propagaÃÃo e chaveamento de sinais codificados. Baseados nas caracterÃsticas de TransmissÃo (T) e Taxa de extinÃÃo (XR) fizemos um estudo do dispositivo como multiplexador /demultiplexador add/drop na recuperaÃÃo de pulsos codificados. / This work, in addition the chapters which involves both theory and definitions, was basically divided three studies: First (chapter 4),we present a numerical investigation of the performance of a bandpass filter composed of an all-optical directional coupler, followed by two double bars Bragg recorded symmetrically equal outputs in their arms. This configuration features a Michelson interferometer with characteristics of an add/ drop filter. The transmission characteristics (T), extinction rate (XR) and "crosstalk" (XT) were studied based on the application of a CW signal (continuous wave) into the device. Theory of coupled modes and the Runge Kutta fourth order were applied respectively to solve the coupled differential equations. This is the first study considering the nonlinearity of the coupler and the linearity of Bragg gratings. The device features a highly nonlinear behavior as a function of dephasing between the amplitudes of the reflected beams and depending on the input power. In a second step (section 5), the propagation and switching of ultrashort pulse (~ 2PS) Michelson interferometer using an optical fiber. In this study the performance of the interferometer is studied as a function of the nonlinear characteristics of the coupler and Bragg gratings. The numerical studies were made from the coupled mode equations solved using the Runge-Kutta 4th order. The pulse switching characteristics were analyzed as a function of input power and applied to one dephasing Bragg gratings. The transmission characteristics (T), extinction coefficient (XR), "crosstalk" (XT), the compression factor (CF)and shape of the pulses were analyzed for different values of phase and different input powers. We use three values of input power: below the critical power (1W = P0), equal to the critical power (P0 = 1.73W) and above the critical power (P0 = 1.95W). Through this study, it is found that the transmission rate of extinction, "crosstalk" and compression factor depends on the power of the pump device inserted into the gap and applied The Michelson interferometer fiber implement major component with applications in optical networks, such as demultiplexers add/drop. This device has attracted considerable interest in the field of telecommunications due to its ability of high transmission rates. In the third place was presented a numerical simulation study of the performance of encoding and decoding of short optical pulses (ps) systems OCDMA (Optical Code Division Multiple Access based on FBG (Fiber Bragg Grating ) where codes are inserted through discrete jumps in the optical phase ( &#960;). For generation of coded pulses were used Gold codes obtained analytically. We look at how the inclusion of additional codes affect the autocorrelation and cross correlation.The Michelson interferometer initially studied Chapters 4 was used for propagation and switching of encrypted signals. Based on the characteristics of transmission (T) and extinction rate (XR) did a study of the device as multiplexer/demultiplexer add / drop in the recovery of coded pulses.
18

MPEG Z/Alpha and high-resolution MPEG / MPEG Z/Alpha och högupplösande MPEG-video

Ziegler, Gernot January 2003 (has links)
The progression of technical development has yielded practicable camera systems for the acquisition of so called depth maps, images with depth information. Images and movies with depth information open the door for new types of applications in the area of computer graphics and vision. That implies that they will need to be processed in all increasing volumes. Increased depth image processing puts forth the demand for a standardized data format for the exchange of image data with depth information, both still and animated. Software to convert acquired depth data to such videoformats is highly necessary. This diploma thesis sheds light on many of the issues that come with this new task group. It spans from data acquisition over readily available software for the data encoding to possible future applications. Further, a software architecture fulfilling all of the mentioned demands is presented. The encoder is comprised of a collection of UNIX programs that generate MPEG Z/Alpha, an MPEG2 based video format. MPEG Z/Alpha contains beside MPEG2's standard data streams one extra data stream to store image depth information (and transparency). The decoder suite, called TexMPEG, is a C library for the in-memory decompression of MPEG Z/Alpha. Much effort has been put into video decoder parallelization, and TexMPEG is now capable of decoding multiple video streams, not only in parallel internally, but also with inherent frame synchronization between parallely decoded MPEG videos.

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