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Parameters of Communication Systems Based on OFDM-CDMA
Blumenstein, Jiří ; Kocur,, Dušan (referee) ; Baudoin, Genevieve (referee) ; Fedra, Zbyněk (advisor)
Cíl disertační práce leží v oblasti modelování a vyhodnocení bezdrátových komunikačních systémů s dvojrozměrným rozprostíráním signálu a jejich klíčových parametrů v závislosti na vybraných vlastnostech moderního bezdrátového komunikačního řetězce. Výzkumné metody použité v této práci spočívají především ve vývoji softwarového simulátoru pro prostředí Matlab, s jehož pomocí, a s využitím statistického přístupu, jsou navržené algoritmy ověřeny. Dále je použit simulátor fyzické vrstvy dle 3rd Generation Partnership Project Long Term Evolution (3GPP LTE), vyvinutý na Technické univerzitě ve Vídni. Tento představuje ideální platformu pro implementaci metody dvojrozměrného (2D) rozprostírání a její vyhodnocení s přihlédnutím k současným bezdrátovým komunikačním systémům. Zjištění prezentovaná v této práci představují především ověření účinnosti systému nazvaného jako Variable Spreading Factor - Orthogonal Code Frequency Division Multiplex (VSF-OFCDM), který využívá principu 2D rozprostírání signálu a zjištění, že VSF-OFCDM systém překonává systémy využívající Orthogonal Division Frequency Multiplex (OFDM), nebo Code Division Multiple Access (CDMA). Dále byla navržena metoda 2D rozprostírání signálu v systému LTE, kde se též potvrdila její účinnost. Díky účinnějšímu potlačení vlivu rychlé variace přenosového kanálu v závislosti na frekvenci a čase, dosahuje systém VSF-OFCDM znatelně vyšší datové prostupnosti.
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Simulation and implementation of the audio power amplifier
Svadbík, Pavel ; Kratochvíl, Tomáš (referee) ; Šotner, Roman (advisor)
This work deals with simulation and analysis of audio power amplifiers of various concepts and classes. The theoretical part presents the basic necessary knowledge of electrical concepts and principles necessary for mastery of issues that this work deals. For each simulated circuit are described the basic operating principles and evaluated the results of the analysis. Based on the results of the analysis is chosen circuit, which is experimentally realized and measurement. In conclusion discusses the parameters obtained by simulations and practical measurements, and are fully assessed characteristics realized amplifier.
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The Design Methods of Equipments for Audio
Kondler, Radim ; Vrba, Kamil (referee) ; Mišurec, Jiří (advisor)
The work is focused on equipment used in audio, such as a loudspeaker crossovers, amplifiers and preamplifiers. There are theoretically described loudspeaker crossovers, their parameters, types of structures derived from the frequency filters with their parameters. Further deals about audio amplifiers and both voltage and power, their theories, parameters, and distribution.
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Quadrophonic audio amplifier for home use
Gavlák, Antonín ; Kratochvíl, Tomáš (referee) ; Brančík, Lubomír (advisor)
This bachelor work describes the design quadraphonic audio amplifiers for home use that works in class AB. The proposal includes a correction preamplifier integrated circuit LM1036 and power amplifier monolithic integrated circuit LM3886 to the output impedance of 8 with appropriate cooling power element. The work also deals with suitable power supply units and soft start circuit for the amplifier. The work contains materials for the construction of a functional prototype of the low-frequency power amplifier and the results of laboratory measurements.
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Controlled power generator of current impulses
Gabriel, Viktor ; Vrba, Kamil (referee) ; Rampl, Ivan (advisor)
The goal of this thesis is to design and realise microprocessor-controlled generator of current impulses, which are being brought in induction load. Thesis contains description of individual functional generator parts, mainly microprocessor program equipment. The text also aims for inductor design as an induction load and other solutions of power parts with the selection of the most suitable one. The generator of current impulses itself is realised on two-sided printed circuit board.
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High Efficiency Microwave Power Amplifiers - Laboratory Experiment
Gajzler, Jakub ; Svačina, Jiří (referee) ; Urbanec, Tomáš (advisor)
This Diploma thesis deals with methods that increase efficiency of transistor amplifiers. In the first part of the thesis we describe theoretical background of the constructions of power amplifiers. At first we deal with the classical method that is concerned with a change of position of the static operating point. Secondly we cover the multi harmonic manipulation method (MHM). This method is concerned with a proper loading of particular harmonic components and consequential shaping of voltage runs and currents on the collector. In the second part of the work we have constructed the substitutes of particular accesses. Constructed classes are AB, F and FMHM. Basic S parameters and output signal spectrum were measured. We can see from the calculated efficiencies AB = 11%, F = 16% a Fmhm = 18%, big increase of efficiency F and FMHM only by changing output network.
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Design of switching class audio power amplifier
Bronec, David ; Kratochvíl, Tomáš (referee) ; Brančík, Lubomír (advisor)
This bachelor thesis is dealing with the issues of the switched category output amplifiers and its aim is to design and to construct a stereo amplifier with the energy output about 100W. The amplifier is constructed in the switched category D. The design of the corrective preamplifier with the correction of depths, heights and the balance functions is also described. Furthermore, this thesis deals with the description of the switched power supply with the TOPswitch control circuit. The design is also supplemented by the simulations and the printed circuits of each part. There are also some photographs of the device and the measurement protocol is included too.
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Solid State Power Amplifier for the L-Band
Pecen, Vojtěch ; Vondra, Vlastimil (referee) ; Kasal, Miroslav (advisor)
The goal of this diploma's thesis is to create a design of a two stages amplifier working in a band reserved for the secondary surveillance radar at the frequency of 1090 MHz. Output power of the amplifier should be 20 W and efficiency should be as high as possible. Because of this the second stage is designed in class C. Contents of this diploma's thesis include a theoretical analysis, simulations of the amplifier parameters, comparison of the Ansys Designer and AWR Microwave Office simulation programs and design of both stages of the amplifier, followed by a comparison of the measured parameters with the simulations.
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Voltage amplifier for Electrical field generation
Nedbal, Jan ; Szabó, Zoltán (referee) ; Kubásek, Radek (advisor)
This bachelor’s thesis is about design and practical realization of the voltage amplifier for generating an electric field defined trace. First part is introduced design of function generator and a DC power supply symmetric. In the second part is the design and simulation of power amplifier in class A and high voltage DC source. The last part is consists of measurements on a function generator, power amplifier and high voltage DC source.
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Low-frequency Power Amplifiers
Matějka, Vojtěch ; Vorel, Pavel (referee) ; Patočka, Miroslav (advisor)
The aim of my bachelor thesis was to design a low-frequency amplifier with some specific parameters. The thesis includes several different connections of known and used amplifiers which are somehow unique or revolutionary. Also it contains the description of classes, the distortion and the structure of amplifiers. The low-frequency amplifier was designed with emphasis on resulting parameters. A design of a printed circuit and the prototype of the board were made. Then the resultant amplifier was modified and adjusted and finally its parameters were measured.
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