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Laboratory Switching Power Supply
Slezák, Jakub ; Petržela, Jiří (referee) ; Šebesta, Jiří (advisor)
This bachelor’s thesis is concerned with design switching power supply based on forward converter with output voltage regulated in the range of 3 to 30V and load current to 1 A. First of all, it discusses the theoretical solution of basic types of converters and switching power supply problems. Followed by a proposal of various parts source, which was first established in the test version on the test board. Then was proposed printed circuit board and complete mechanical solutions. Source is also equipped with digital modules for measuring voltage and current, and is protected against overload.
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VHF/UHF Front-End for Software Receiver
Losenický, Roman ; Vágner, Petr (referee) ; Šebesta, Jiří (advisor)
The first part of this work contains the detailed analysis of the basic VHF and UHF receiver characteristics. The most important parameters, like Noise figure, selection or gain, are qualified shortly. The following chapter analyzes above-mentioned parameters and shows some calculations and analysis to design a receiver. In the third part the receiver design is proceed. It specifies a basic block diagram. The base of design is formed by a mixer SRA-1+, which choice is not part of this project. Design of preselectors is the main goal of the project. They use BF998 FET transistors and band pass filters determining three frequency bands: 140-145 MHz, 220-230 MHz and 420-430 MHz. Filtered signals go on into the channel selector afterwards. The user can determine , which one of the three input signals will be routed to the mixer, using a switching diode HSMP3823. Each part, including preselector amplifier and filters, is placed into the separated tinned boxes. These boxes are linked with the switching circuit by the coaxial line.
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Automatic Antenna Tuner
Šváb, Jaroslav ; Lukeš, Zbyněk (referee) ; Šebesta, Jiří (advisor)
This degree work deals with the design and implementation of an automatic antenna tuner for short-wave transmitters. The device works within the short-wave range in (1.5 MHz - 30 MHz) band according to the selection of the given frequency. Its principle is that the tuner has a small range of adapted impedances, but it is usually sufficient for fine tuning of most deviations in the system of antenna 50 - feeder 50 - transceiver outlet 50 . It is also equipped with memories which the settings for the individual bands or frequency segments are stored into. Then the transition from one band to another is quick, easy and, first of all, safe, which is a great advantage. In automatic mode, a SWR limit from which the tuner should start to tune can be set. Interconnection with a TRX is not necessary in a fully automatic mode, the device tunes automatically after keying if the set limit of SWR has been exceeded. The automatic tuning is very quick with this device, if the antenna being tuned is not stored in the memory the tuning lasts ca 0.5 - 6 s, if the tuner uses the memory. It could be said that the work with the tuner is without problems, it is possible to learn to control it in a short time. The tuner is small and light. The result of the whole project is a compact device controlled by the user by means of push buttons.
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Two-stroke Engine Pre-ignition Controller with Microcontroller
Veselý, Tomáš ; Vorel, Pavel (referee) ; Šebesta, Jiří (advisor)
This paper deals with the problem of two-stroke engine pre-ignition controller with the use of microcontroller for single-cylinder engine and double-cylinder engine. The mechanical design is drawn for motorcycles JAWA and ČZ and for engines of the same mechanical type. The establishment uses non-contact status analysis of engine with non-electric sensor. The very important thing for the design is the simplicity of the establishment. The other important thing is the minimisation of mechanical arrangement of engine and the vehicle as a whole. The importance of this establishment is non-contact switching and the possibility of changing pre-ignition maps depending on the number of rotations per minute, the temperature and the load of the engine.
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DC-AC converter 12 V / 230 V for car applications
Jezerčák, Martin ; Šebesta, Jiří (referee) ; Brančík, Lubomír (advisor)
This work deals with a proposal for increasing DC/AC inverter for use in cars to power electronic devices on 230 V. This work is divided into two parts, theoretical and practical. It consists of three chapters. In the first chapter I developed a voltage converter, its breakdown, a breakdown by function, and the usage of individual connections. The proposal converter with the integrated circuit IR2153 is described in the second chapter. In the third chapter I processed readings and I visualized graphical dependencies of converter that was produced and purchased.
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LCD Matrix Display Driver
Satora, Ondřej ; Šebesta, Jiří (referee) ; Vágner, Petr (advisor)
The aim of my semestral project is a realisation of a driver matrix LCD from older NOKIA mobile phones with the PCD8544 chip. This driver is situated between an LCD and a device using it. The proposed driver should cover rendering graphical elements for the main application, thus making work with the LCD easier. This saves memory needed for using the LCD as well as computing time.
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Precise measurement of semiconductors
Smělík, Martin ; Šebesta, Jiří (referee) ; Dřínovský, Jiří (advisor)
The aim of this bachelor´s thesis was design a laboratory workplace for precise measurement of the stability output parameters of semiconductors. The thermostat is also part of this workplace. The thermostat is maintaining a constant temperature measured semiconductor. The entire laboratory preparation is controlled by a computer via USB. The program is created in control environment Agilent VEE for automatic measurement that semiconductor components.
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Development board with 32-bit ARM-based processor
Jůn, Lukáš ; Šebesta, Jiří (referee) ; Frýza, Tomáš (advisor)
The content of this thesis is to create a detailed description of 32-bit ARM-based processors. Reader will be inform about the each one of the family of ARM-based processor, about the options of creating applications for these CPUs. The Applications are commonly developed by using the C/C++ language. This text also deal's with the development environments. These tools are making easier the development of new applications. This thesis also contains a complete design and description of development board with Atmel AT91SAM7S64 MCU (with sample of source code included).
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