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Spread spectrum modulator
Lejsková, Alena ; Kováč, Michal (referee) ; Maršálek, Roman (advisor)
This thesis deals with a method of spectrum-spreading of the data signals transmitted in the radio channel. There exist three different ways of spreading application, they uses pseudorandom sequences and also orthogonal sequences. In these systems we can find various kinds of modulations, one of them (Quadrature Phase Shift Keying) is shown at the end of the thesis. Spectrum spreading orthogonal multiplex OFDM is based on this method. The thesis wants to present the principle of the spectrum spreading method and the description of systems, transmitters and receivers that are using this method.
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Software defined optical network
Kloda, Tomáš ; Horváth, Tomáš (referee) ; Kočí, Lukáš (advisor)
This thesis is focused on explanation of software defined networking and communication via OpenFlow protocol with description of transmitted messages. This thesis deals with software defined optical networking, which describes combinations of OpenFlow with other technologies and methods to control the optical path. In another part, the thesis is focused on the description of the physical layer of optical backbone networks, where there is a description of multiplexers, DWDM technology and optical elements. This thesis also includes designs of software defined optical network with implementation of extended header for transmission in the optical domain. Outcome of this thesis are simulations, which include synchronization between the elements during initialization of software defined optical network with occurence of delay. At the end, the thesis is focused on simulations of the actual data transfer within the proposed software defined optical network.
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Simultaneous transmission of photonic services in fibre optics
Látal, Michal ; Horváth, Tomáš (referee) ; Münster, Petr (advisor)
Diploma thesis focuses on simultaneous transmission of selected photonic services by one single-mode optical fiber. The thesis deals with the problem of common transmission of multiple photonic services by one optical fiber using the wavelength division multiplex technology. Furthermore, the origin and influence of nonlinear phenomena accompanying the simultaneous transmission of photonic services are described. Except common data transmission with a bitrate of 10 Gbit/s, a common high-speed data signal transmission with a bitrate of 200 Gbit/s, accurate time transmission and high-power sensor signal are considered. During the aimultaneous transmission of selected photonic services, the measurement of the transmission parameters was performed for various variants of the simultaneous transmission arrangement. In particular, the influence of nonlinear phenomena and possible mutual interference of individual transmission channels at 50 and 100 GHz between signals was analyzed.
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Usage of polarization multiplexing in optical access networks
Jakoubek, Petr ; Čučka, Milan (referee) ; Šifta, Radim (advisor)
This thesis reviews polarization multiplexing and its similarities, advantages and disadvantages to other types of multiplexing methods. The basics of optical fibers and its effects on transmission are discussed in terms of commonly used multiplexes. Additionally, divisions of optical access networks and multiplexing methods which could be used simultaneously with polarization multiplexing along with active and passive elements used for high-speed transmission such as polarization multiplex are described. Practical measurements of temperature influence to polarization and signal crosstalk in the amount of 70 °C and -40 °C are also included. The practical and theoretical measurements on 1 Gb signal led in G.652.D fiber for different situations are examined. Measurements containing 1 Gb signal includes test on triple play services (voice, video, data). First practical measurement on 1 Gb transmission shows how white noise, representing analog television, transmitted in the first polarization beam affects the signal in the second polarization beam. Second practical measurements show how two data streams transmitted through a single fiber at the same wavelength, but different polarization beams, creates a full duplex connection between two network elements. Results confirm the possibility on the usage of polarization multiplexing in optical access networks at common temperatures.
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Utilization of MHP platform in DVB-T
Janík, Lukáš ; Balík, Miroslav (referee) ; Kohoutek, Michal (advisor)
This bachelor‘s thesis solves the problem of digital television and set-top boxes, more precisely MHP platform and its use in DVB-T. In the first chapters I talk about analogue terrestrial broadcasting and necessity of transition to digital broadcasting. In addition, you can read about the necessity of the MHP platform implementation as the stable part of the DVB-T. I analyse this platform and describe the pros, cons and possibilities for its use at presen and in the future. I mention the different types of set-top boxes and their main manufacturers. I also describe an application development cycle, from writing the source code, despite testing in the development environment of IRT, respectively Osmosys, until loading to the real set-topbox. I also represent here the practical part of my bachelor‘s thesis, which was the development of chat client for the MHP platform and it allows two users to communicate in real time. This application I tested in the IRT and I uploaded it to the real set-top box. Next I analyze Java programming language, such as the appropriate development language for this platform. I mention the HAVi standard and its relevancy in usage of MHP platform.
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Possibilities of increasing the throughput of optical fiber industrial networks
Čičmanský, Tomáš ; Münster, Petr (referee) ; Filka, Miloslav (advisor)
Diploma thesis deals with problems of industrial networks using optical fiber as the main transmission lines. The task of the diploma work is to study and summarize the issues of industrial networks as well as the ways to increase their transmission capacity. In telecommunications and computer networks are generally used multiplexes, thanks to which we are able to achieve the desired transmission capacity. Consequently, the following work deals with the selection of the adequate solutions using described multiplexes as well as other transmission methods. The aim of the diploma work is to compare various renovation techniques of an old industrial network. Using this network as an example the work should demonstrate the individual problems and their solutions while considering different types of methods used. Based on the price, the performance and the difficulty to install other devices and transmission media we are able to select the appropriate solution for optical link.
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Measurement of DVB-T transmission over simulated fading channel
Vašut, Jakub ; Kratochvíl, Tomáš (referee) ; Štukavec, Radim (advisor)
The goal of this bachelor’s thesis is to study basic functional elements of coder and modulator of standart DVB-T. Another goal is to study documentation of DVB-T modulator DTA-110T and ASI/SDI adapter DTA-145 by DekTec. Also is described software channel simulator DTC-305 and parameter settings of simulated fading channel. Fading channels are measured and assigned their effect on quality of received DVB-T signal.
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Error Analysis in Measurements on the MPEG-2 TS Digital TV Transmision
Chrobák, Jan ; Slanina, Martin (referee) ; Kratochvíl, Tomáš (advisor)
This essay shows up the monitoring and error measuring in transportation stream MPEG-2 TS during the digital TV broadcat recieving accordingly to the DVB standard. There are DVB definitions and standards for transportation stream transmition, decoding conditions and service informations chart described in the introduction of this essay. The measuring decoder R&S DVMD has been used for experimental measuring in the laboratory. This decoder enables long-time monitoring and automatized errors evaluation of particular priorities. The processed results of DVB-T multiplex 1 and 2 and DVB-S, paket CS link, TV broadcat recieving are the part of this essay as well.
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Design of Multiplex Optical Fibre Link
Krejča, Libor ; Křivánek, Vítězslav (referee) ; Kyselák, Martin (advisor)
In this thesis I consider problems of optical multiplexers, optical amplifiers and designing optical networks with this components. CWDM and DWDM are the most common used multiplexers today. I describe principles of realization multiplexers from basic level to realization in WDM networks. EDFA is also common used amplifier today and I describe his internal structure and how it works. Today, we can observe many realization of optical netwoks with Raman amplifiers, especially in long haul networks. Raman amplifier is characterized in brief. In next chapter I describe the design of optical communication systems and the main designing equations are explained. Then I used the equations for example of designing optical communication system with multiplexers, EDFAs and other components, which are needed for function of the system. In last chapter I explain mathematical model of signal propagation in optical fiber called nonlinear Schrodinger equation, which includes main optical effects in fiber like chromatic dispersion or Kerr effect. The simulation model and his numeric solution was designed including PMD effect, the simulation model is programmed in MATLAB.
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