National Repository of Grey Literature 114 records found  beginprevious21 - 30nextend  jump to record: Search took 0.01 seconds. 
Spectral characteristics in fiber optics
Chleboun, Jiří ; Tejkal, Vladimír (referee) ; Šporik, Jan (advisor)
This bachelor’s thesis is focused on the influence of attenuation and dispersion glass and plastic optical fibers in optical transmission system. Theory of optical transmission is discussed in the theoretical part, it is defined term like spectral attenution characteristic and its division into transmission bands. Sources and detectors are itemized further, which are used for optical transmissions in fiber optics. The thesis describes the most occured effects, which influenced transmission parameters of optical fiber, like optical attenution, dispersion and aspectual polarization dispersion. Theory of plastic optical fibers is processed at the end of theoretical part of thesis. It is also processed advantages, disadvantages and useage of plastic optical fibers and they are consequently compare with glass fibers. Comparison is focused mainly on attenuation, transmission properties and useage on these types of fibers in telecommunication. Representation of spectral attenution characteristics in programme MATLAB is practical output of the bachelor´s thesis. Created programme approximates points which are got from measure optical attenuation by the Lagrange interpolation polynomial.
Verification of parameters of passive optical components on short wavelengths
Látal, Michal ; Filka, Miloslav (referee) ; Vojtěch, Josef (advisor)
Semestral thesis deals with the basic theoretical knowledge in the field of optics, light propagation and optical fibers. It describes in detail the optical transmission system and its associated issues, such as the attenuation of optical fibers or differently caused dispersion. The main part of this work is a description of each passive optical elements, their production technologies and applications in optical communications. Within the optical connection its radiation sources and detectors of optical radiation are explained. The last practical part is focused on the measurement of insertion loss provided by passive optical components.
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.
Analysis and construction of an optical fibre tunable attenuator for telecommunication applications
Prokop, Daniel ; Eliáš, Josef (referee) ; Urban, František (advisor)
This paper deals with the possibilities of designing the module for control of the attenuation of the optical signal. The paper describes basics of ber optic transmission and beam e ects. Variants of attenuation cells are characterized in this paper and based on the ndings a solution of the module for control of the attenuation of the optical signal is proposed. Practical section of the thesis deals with the design and physical construction of module for control of the attenuation of the optical signal using MEMS variable optical attenuator.
Procedurally Generated Lens Flare Effect for Blender
Volf, Petr ; Milet, Tomáš (referee) ; Chlubna, Tomáš (advisor)
Lens flare is an image artefact caused by unintended reflection of light in camera's lens system. The goal of this project is simulation of this phenomena in open source 3D content creation suite Blender. The generated effect is then composited into final image. The project is designed as an add-on. The add-on allows user to customize several parameters to achieve the desired result.
Optical fiber sensor based on Michelson interferometer
Kopáč, Ondřej ; Grenar, David (referee) ; Čučka, Milan (advisor)
This bachelor thesis deals with description and simulation of Michelson unbalance interferometer and description of fiber optic sensors. The simulation is realized by MatLab. The thesis also described basic optical phenomena, types of optical fibers and two types of interferometric detection. The thesis also deals with description of measurements and their results.
Castables with Inorganic Nanofibers
Zogata, Stanislav ; Keršnerová,, Lucie (referee) ; Sokolář, Radomír (advisor)
This work deals with the use of inorganic nanofibers in refractory castables. The thesis describes some of the results of previously conducted research on nanofibers. Also description of nanofibres, production and distribution. The experimental part is focused on studying the interaction of Al2O3 and SiO2 nanofibres with aluminate cement. The main subject of investigation is a dispersion of nanofibers using a surfactant and ultrasonication.
The Optical Link Error-Rate Determination
Joch, Antonín ; Kapoun, Vladimír (referee) ; Kyselák, Martin (advisor)
The master thesis discusses physical causes of light polarization and problems brought by nascence of Polarization Mode Dispersion (PMD). These problems occur especially by high speed systems on optical cable traces. The thesis deals with actuation of transmitted signal by influence of Inter Symbol Interference and it also deals with methods for its measuring and compensation. As a results of measurements are in text presented data provided by EXFO Electro-Optical Engineering Inc. Company. Significant part of the thesis focuses on optical link Bit Error Rate (BER) which is connected with Signal to Noise Ratio (SNR) and signal quality (Q-factor). Further on it is possible to find in text about so called eye diagram which is display mode that shows influence of communication channel on shape of the transmitted signal. To this diagram is related another one called constellation diagram which describes modulation mode and makes it possible to map dispersion of signal points around their nominal values. In connection with so called trajectory it makes vector diagram. Practical part includes depiction of these diagrams in MATLAB development environment.
Testing of optical networks
Šimoník, Jan ; Horváth, Tomáš (referee) ; Filka, Miloslav (advisor)
The aim of this bachelor thesis is to describe testing of optical networks physical layer by norms and recommendations (CSN, ITU and RFC). The first chapter provides a description of the individual optical fibers, their division and a brief description of each type. In the next part of this thesis, the methods and procedures for testing the various parameters of optical networks are described, according to specific standards and recommendations. The issue of testing quality of services is also described, primarily focused on triple play services, which are operated at optical access networks. The following is a description of the issue of access and transport networks, a draft of methodology for testing the physical layer of these networks is given. In conclusion, there is a chapter describing the practical measurements made on a passive optical network. In the annexes of this thesis the limit parameters of optical fibers used for the measurements and draft of the content for measuring protocol are listed.
Numerical solutions of EMC problems of small airplanes
Šeděnka, Vladimír ; Dědková, Jarmila (referee) ; Mazánek, Miloš (referee) ; Raida, Zbyněk (advisor)
Disertace popisuje současné problémy v certifikaci malých letadel, které by se měly v budoucnu řešit numerickým modelováním. Tento postup má zefektivnit návrh a zlevnit certifikaci letadel. Práce je úzce spjata s projektem HIRF-SE, který se problematikou certifikace letadel numerickými metodami zabývá. Podstatná část práce je věnována popisu dvou modulů pro platformu HIRF-SE: řešič BUTFE založený na metodě konečných prvků v časové oblasti a budicí nástroj BUTFE_EXC. Práce popisuje řešení pohlcujících okrajových podmínek, modelování disperzních a anizotropních materiálů a aproximaci tenkých drátů. Speciální pozornost je věnována řešení aproximace tenkých drátů s ostrými ohyby, jejíž současná formulace způsobuje překryvy mezi jednotlivými segmenty drátu.

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