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Microwave Modulators Based on Sixports
Dušek, Martin ; Bezoušek, Pavel (referee) ; Galajda, Pavol (referee) ; Šebesta, Jiří (advisor)
This doctoral thesis is focused on problems of modulators based on six-ports. It begins with description of current state of the art of six-ports used like modulators, their transfer functions and SIW technology. A design part of this thesis consists from experimental six-port based on substrate integrated waveguide (SIW) technology. There is presented step-by-step development of this six-port using this technology and also there is introduced micro-strip technology based six-port. Final design of six-ports and variable impedances were measured, the results are discussed and compared with expected ones in next chapters. Second part of this thesis deals with influences of internal parameters of six-ports to final signal transmission and derives theirs transfer functions for more than one reflection in structure. The computation results are compared with experimental measurements for fixed loads. With using of ideal loads sweeps, modulations with shaped input signals were calculated. For designed variables impedances, there was founded the optimal biasing points for demanded IQ diagram and discussed which from tested active circuit is suitable. In the last part there are shown results of experiment with these variable loads connected to both types of designed six-ports.
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Laboratory High-Frequency Generator
Konzal, Jan ; Záplata, Filip (referee) ; Šebesta, Jiří (advisor)
This thesis describes a proposal of laboratory high frequency generator based on the principle of indirect analogue synthesis with a phase sling. The first part of the work describes the principle of a direct numerical and indirect analogue synthesis. Frequency range of the designed generator is up to 900 MHz. The output of the generator is designed to be up to 12dBm. Output impedance is 50 . To reach a frequency of oscillation lower than 800 MHz, the principle of fusion is used. Further, the control was suggested to be carried out by a microprocessor. Operating is realized using a keyboard and a rotary encoder.
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Laboratory Function Generator
Trnkus, Andrej ; Kubíček, Michal (referee) ; Šebesta, Jiří (advisor)
This thesis deals with the design of function generators based on direct digital synthesis. It examines software and hardware realisation of a generator of sinus, triangle and rectangle shaped signal, frequency sweep, pulse-width modulation and data transfer after the SPI data bus. It also focuses on the user interface display on an LCD display, control by a rotational encoder and the buttons of the microcontroller periphery of an AVR class.
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Simulator for Passive Multi-Static Radar using WiFi/WiMAX
Sládek, Ondřej ; Kubíček, Michal (referee) ; Šebesta, Jiří (advisor)
This master’s thesis deals with the concept of passive multistatic radar. The radar system exploits WiFi or WiMAX transmitters as the source of radiolocation signal. The transmitters are considered non-cooperative. The master’s thesis evaluates limitations arising from utilization of WiFi or WiMAX signals. A Matlab simulator was created as a part of the thesis, which was used to verify the basic idea behind this concept. Based on the results of real-life simulations, conclusions are suggested towards a possible application of WiFi/WiMAX radar.
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XML based framework for transformation of Java source code
Šebesta, Jiří ; Parízek, Pavel (referee) ; Poch, Tomáš (advisor)
Goal of the thesis was to provide transformation framework for Java sources based on well established XML technologies. The framework defines XML Schema for representation of Java sources. Java 1.5 sources can be parsed and stored to XML. Means for transformation and analysis are based on the JAXB technology. Several example transformations (refactoring, predicate abstraction) are also part of the framework. The framework is able to transform XML files back to the Java sources.
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Algorithm visualization using user-defined scripts
Šebesta, Jiří ; Šerý, Ondřej (referee) ; Ježek, Pavel (advisor)
The goal of this thesis was to create a program (AlgoShow) for explanatory chart of algorithms' process. Algorithms are written in the form of user-defined scripts that offers various functions for graphic presentation of algorithm's process. The thesis describes the program from both user's and programmer's points of view. The text includes short introduction into algorithm visualization, comparison of the AlgoShow program with another similar tools, description of design and implementation of the program including the method of script's interpretation. The thesis also includes characterization of essential program's features and detailed description of scripting language.
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RF Power Amplifiers
Hrazděra, Tomáš ; Hubík,, Vladimír (referee) ; Šebesta, Jiří (advisor)
This work deals with high-frequency power amplifiers. In the theoretical part are briefly summarized the general characteristics and properties of particular working classes of amplifiers focusing on their efficiency. The next section is aimed on design of high-frequency power amplifier for 1296MHz band and its individual components. In this part is desribed design of hybrid combiners - splitters, directional couplers of the coupled lines, amplifiers with RA18H1213G module and power amplifier with transistor BLV958. The work also includes the results of simulations of designed circuit, realization procedure and the measured parameters of manufactured components. In conclusion of this work the theoretical and measured values are compared.
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Inertial Navigation Unit
Dvořák, Jan ; Hubík,, Vladimír (referee) ; Šebesta, Jiří (advisor)
This thesis is focused on the design and realisation of inertial navigation unit INS. The unit is capable to measure, store and send data to a PC in real-time for a later offline processing. The first part of the thesis introduces the reader with the basic principles of accelerometers, gyroscopes and MEMS sensors. An introduction to coordinate systems and measuring errors is also included. The second and third part of the thesis deals with the analysis of the solution and the implementation of the INS unit. The fourth part of the document is dedicated to the software for the INS unit. This thesis concludes with explanation how the gathered data are processed.
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Wideband Amplifier Final Stage 5kHz - 1,5 GHz
Galajda, Jan ; Šebesta, Jiří (referee) ; Urbanec, Tomáš (advisor)
This work is focused on the problem of design of the wideband amplifier final stage, which is designed as a replacement for the old insufficient amplifier, which works in the frequency band from 5 KHz to 1.5 GHz. First part of the work is dedicated to theoretical introduction of the problem. Second part of the work describes the created matlab scripts for automatic measurement of the amplifiers parameters via SCPI commands. The third part describes choice of the new active element based on the measured parameters of the original amplifier.
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