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Polarization mode dispersion
Turský, Aleš ; Dostál, Otto (referee) ; Filka, Miloslav (advisor)
The work deals with dispersive effects of single mode fibers. We learn about the chromatic dispersion, the main attention is paid to the Polarization Mode Dispersion. We clarify the root cause origin of the Polarization Mode Dispersion describing parameters and its effect on transmitted data. Further on, the works dedicates to measure methods of the Polarization Mode Dispersion which is the interferometric method or the POTDR method. We explain the ways of the PMD removal at contemporary optic routes and options of PMD compensation by using compensators of various types. There is also mentioned the possibility of profiting from the soliton transmission. The last chapter deals with measuring of a real optic route. It includes measured data and its evaluation due to the ITU-T demands.
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Methodology for the measurement of optical arterial network
Chleboun, Jan ; Dostál, Otto (referee) ; Filka, Miloslav (advisor)
There are methods to extend the transmission channel of optical transmission medium thanks to the development of telecommunications and informatics. Multiplex is a grouping of signals into a single transmission path and wave-division multiplexing is the best reason of use of the maximum fiber optic transmission capacity. The subject of this work is to determine whether a particular transmission path is suitable for such an extension of their capacity and how much. The answer is obtained by measuring the attenuation, the chromatic dispersion and the polarization mode dispersion, whose values are strictly limited and which determine next steps in the expansion of the transmission path, which is comprised by optical medium. Measurement methods determine the nature of the measured route and its current transmission capacities. Draft of the measurement methodology, which ensures the correct procedures during a possible transition to higher speeds is the output of this work. Thanks to the acquired characteristics of the BAPS (the Brno Academic Computer Network), the bit rate 40 Gb/s can be provided on this part of the network under the conditions of the introduction of certain countermeasures, particularly the exchange of a connectors on the measured optical lines. As for the back reflection lines in excess of the standard recommendation and pre-emptively on the lines with values with still agree with the return loss. Countermeasure for limiting of the chromatic and the polarization mode dispersion are do not need to stand in the way of a planned transition to a higher rate of the BAPS.
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Data centre project - structured cabling
Hejtmánek, Ondřej ; Dostál, Otto (referee) ; Filka, Miloslav (advisor)
This master’s thesis is concerned with analysis of cabling and cabling systems in data center and with their projection as follows. The part of the work is aimed at the measurement parameters of metal cables which are used in data center with noise. The first part is focused on analyzing the structure of the data center and cabling used in it. The structure of the data center is based on the TIA-942 and consists of an entrance room, main distribution area MDA, horizontal distribution area HDA , zone distribution area ZDA and the equipment distribution area EDA. Divided into backbone cabling and horizontal cabling and use standard and pre-terminated cabling. The measurement results of structured metal cabling with noise are discussed in the next part. There were used these types of cables UTP, FTP and S/FTP. The measurement was performed in the electricity substation and in the laboratory of electromagnetic compatibility. The third part of this work deals with the actual design of structured cabling for the data center. In the first design we use the standard installation, the second preterminated cabling. For both types of installation cost statement is processed (CAPEX). Thesis is also completed with DC design drawings and rack drawings.
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Optical network FTTH
Horníček, Lukáš ; Dostál, Otto (referee) ; Filka, Miloslav (advisor)
The bachelor's thesis „Optical Network FTTH“ is a theoretical and practical analysis of problems of optical access networks with respect to current and prospective trends in the construction and operation of these networks. For the clearness of thesis done divided into 6 chapters. The first five chapters deal with the optical access networks at a theoretical level with a touch of practical knowledge in the academic analysis. The first chapter deals with general concepts networks FTTH and defines the reasons for their occurrence. The second thematic chapter specifies an individual topology implemented in optical networks FTTH, their advantages and disadvantages with respect to transfer capacity and the economic-competitive potential of the network. It is defined by a principled division of optical networks in the active and passive with the definition of network architectures, communication models and protocols. The individual architectures are evaluated for suitability in the deployment of networks FTTH. The third and fourth thematic chapters inform readers with the passive and active access network FTTH infrastructure. Passive infrastructure examines the method of construction used in the past decades and the latest technology microtubing that this networks concept prevailed. The fifth thematic chapter provides Triple Play services and reasons for using these services just for FTTH optical networks. The sixth chapter is a crucial element in this thesis. Results and knowledge acquired in previous chapters is applied to real network model. It is defined by imaginary the village "Fektákov" for which they are created by three case studies covering technical and economic documentation for the realization of a real access FTTH network. This allows compare the modern ways of realization network infrastructure, including central office and subscriber terminal equipment. The results of these three case studies, conclusions are drawn that highlight the strengths and weaknesses of these architectures and also suggest the quality and reliability of these networks and the expected future prospects of development. Conclusion of the thesis is an evaluation of all evidence obtained in this work reflects the author's view on current and expected future developments in optical access networks leading its optical fiber to homes or apartments of all households.
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Keyword Detection in Speech Data
Pfeifer, Václav ; Makáň, Florian (referee) ; Dostál, Otto (referee) ; Balík, Miroslav (advisor)
Speech processing systems have been developed for many years but the integration into devices had started with the deployment of the modern powerful computational systems. This dissertation thesis deals with development of the keyword detection system in speech data. The proposed detection system is based on the Large Margin and Kernel methods and the key part of the system is phoneme classifier. Two hierarchical frame-based classifiers have been proposed -- linear and non-linear. An efficient training algorithm for each of the proposed classifier have been introduced. Simultaneously, classifier based on the Gaussian Mixture Models with the implementation of the hierarchical structure have been proposed. An important part of the detection system is feature extraction and therefor all algorithms were evaluated on the current most common feature techniques. A part of the thesis technical solution was implementation of the keyword detection system in MATLAB and design of the hierarchical phoneme structure for Czech language. All of the proposed algorithms were evaluated for Czech and English language over the DBRS and TIMIT speech corpus.
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Segmentation Methods in Biomedical Image Processing
Mikulka, Jan ; Přibil, Jiří (referee) ; Dostál, Otto (referee) ; Gescheidtová, Eva (advisor)
The PhD thesis deals with modern methods of image processing, especially image segmentation, classification and evaluation of parameters. It is focused primarily on processing medical images of soft tissues obtained by magnetic resonance tomography (MR) and microscopic images of tissues. It is easy to describe edges of the sought objects using of segmented images. The edges found can be useful for further processing of monitored object such as calculating the perimeter, surface and volume evaluation or even three-dimensional shape reconstruction. The proposed solutions can be used for the classification of healthy/unhealthy tissues in MR or other imaging. Application examples of the proposed segmentation methods are shown in this thesis. Research in the area of image segmentation is focused on methods based on solving partial differential equations. This is a modern method for image processing, often called the active contour method. It is of great advantage in the segmentation of real images degraded by noise with fuzzy edges and transitions between objects. The results of the thesis are methods proposed for automatic image segmentation and classification.
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System for administering electronic archives
Balák, Václav ; Burget, Radim (referee) ; Dostál, Otto (advisor)
The objectives of this project are to create a concept of system for multimedia documents management and long-term archiving and its realization. The opening chapters are devoted to theoretical analysis of the expected characteristics of this systém and their implementation in open source document management system Alfresco, which was used for implementation. Other chapters are devoted to modifications made to this system, which are enhancements to work with multimedia content and its metadata. Also possibilities of connecting the system to other systems are mentioned. Finally, this document also describes testing the changes and adjustments according to various criteria.
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Measurement of optical connections
Kučera, Zdeněk ; Dostál, Otto (referee) ; Filka, Miloslav (advisor)
Communication via fiber optical cable (links) is the latest advancement of the transmission media currently used for data transmission. Despite initial problems, using of this medium in recent years has greatly expanded due to their indisputable advantages. Optical cable is a great combination of reliability and security of data transfer. Its constantly improving transmission parameters contribute to the high speeds in the long-distance transmission of data. In the theoretical part of this work some kinds of optical cables are mentioned, also the most important parameters and the most widely used methods of measurement of these cables. Apart from that other methods of joining optical cables and the most used types of optical cables are also mentioned. The values of the decline and reflection, which are led into the device after connecting these parts into the optical lines. The device using the measuring method of the reverse reflection is also described in this thesis altogether with its most important parts and the way of the display of the measured track on the graphic image of the device. The problematics of identification and decline dead zone and the factors influencing the lenght of dead zone – the ability to identify two independent events on the link patchcord of the variable lenght, is also described in details in this thesis. In the practical part a series of measurements and evaluation (numerical and graphical) of the measured values of decline lenghts and identificating dead zones of the OTDR device will be carried out.
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Wireless optical links in LAN and MAN networks
Šporik, Jan ; Dostál, Otto (referee) ; Filka, Miloslav (advisor)
The main aim of this thesis is the design of an optical wireless link that is transmitted in free space, in the atmosphere. The thesis describes the composition of heads of the atmospheric optical link. One part of this work focuses on the issue of the spread of optical beam in the atmosphere. The facts which have a major impact on the transmission of optical radiation in free space are pointed out here as well. In this work phenomena of absorption, refraction of light, turbulence and dispersion are discussed. Wavelengths spread in the atmosphere with different decline and therefore this thesis provides an analysis of the use of wavelengths between 750 and 1600 nm depending on the meteorological visibility. It describes the basis of the design of AOS through stationary model using power balance equation. It depicts the description of the statistical model, which makes possible to determine the availability on the basis of probability. Current possibilities of AOS are in general described in this work. The practical part of the work is focused on the design of simulation model of transmitter and receiver AOS in the program Pspice. The receiver and transmitter are designed to replace transiver in the media converter. The receiver plays a key role, and therefore big part of the thesis is given to it. Receiver model is composed of a photodiode and of an transimpedance amplifier. The receiver circuit has been tested. The model of transmitter shows the principle of modulating of current, which flows in laser diode. This work does not carried the model of atmosphere, which would serve as a link between the receiver and the transmitter. The circuit of the receiver is subjected to the noise analysis. Parameter NEP and SNR is designed. Link budget is calculated for models of the receivers and the transmitters. The maximum distance of heads is set based on the requirements for a BER error rate which combine this condition. The design of the practical implementation results from the models of transmitters and receivers. Printed circuit boards are designed in EAGLE. Within the frame of this thesis no curcuit diagram is carried out.
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Polymer optical fibers - POF
Mitrič, Martin ; Dostál, Otto (referee) ; Filka, Miloslav (advisor)
Polymer Optical Fibers - POF in recent years reach into values attenuation about 10 dB • km-1. This is the value that makes these fibers applicable for data transmissions over short distances. Between the great advantages of these fibers include simple installation and easy preparation of the connectors. The aim of of this work is to introduce the issue of the POF fiber. The work begins with becoming familiar with different types of fiber POF, their basic characteristics and differences. It also deals with methods of linking these different types of fibers and connectors designed for these fibers. Another chapter focuses on the possible use of these fibers in FTTx networks and their future. Work continues overview of the types of optical access network and transmission design polygon using POF fibers for laboratory purposes. The final part presents the results of measurements of fundamental properties of the POF fiber.
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