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Models of EMC filters
Kejík, Zdeněk ; Šebesta, Jiří (referee) ; Dřínovský, Jiří (advisor)
Basic problems of the EMI mains filter is explained in the introduction of this thesis. These problems appear during the measurement of insertion loss of filters and by design of EMI mains filter. The important problem is uncertainly of the terminating impedances. Eventualities measurement insertion loss of EMI mains filter and motivation of creation filter models are shown. The following part of this project shows the electronic components, from which are realized the EMI mains filter. Parasitic properties of these real devices are also discussed. The circuitry of EMI mains filter is described by the Modified Nodal Voltage Method. The optimization method called Participle Swarm Optimization is introduced, too. Basic principle and terminology are mentioned. The third part of this project is focused on the own filter and spurious components. Influence of own filter and spurious filters components on insertion loss curve are showed. Magnetic factor coefficient k is searched by the optimization method PSO. The last part of this thesis deals with creation of the alternative circuits with spurious filters components. The performances of the alternative circuits were compared with the measured data for symmetrical and asymmetrical measurement setup. The breakages in the insertion loss curve were used for determining the spurious components.
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Direct digital frequency synthesizer
Svoboda, Josef ; Šebesta, Jiří (referee) ; Kasal, Miroslav (advisor)
Direct Digital Frequency Synthesis (DDFS) is a method of producing an analog waveform, usually a sine wave, by generating a time varying signal in digital form a then performing a digital to analog conversion. Because operations within a DDFS device are primarily digital, it can offer fast switching between output frequencies, fine frequency resolution and operation over a broad spectrum of frequencies.
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Control Unit for Church Bell Electric Drive
Bureš, Petr ; Novák, Pavel (referee) ; Šebesta, Jiří (advisor)
This work deals with analysis induction motors. There are described their principle and methods of starting, the engine controls and the stop braking. In terms of this study it was determined the engine controls type for control unit for church bell electric drive design. In next part there is complete hardware and software design of control unit.
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Polyphase modulation generator for radar signal
Hás, Jiří ; Šebesta, Jiří (referee) ; Kolka, Zdeněk (advisor)
The goal of the theses is to propose an idea for a generator of a radar polyphase modulated signal, that will operate at a frequency of 30 MHz. At the beginning of this project, an outline of the basic structure of the generator is proposed and a function of a programable logical perimeter is analyzed. This perimeter, together with an oscillator, generate two mutually phase-shifted rectangular pulses in its outputs. The shift phase of these two pulses is set by a program, and operated by single-chip processor. Those pulses are consequently converted to sinusoidal wave with the help of filters, and the required phase is chosen by the multiplexer, which is also operated by the processor. The phase modulation is realized this way. The output signal of the generator is radiopulse, which subpulses are phase modulated by the described method. Individual parts are solved analogously in this Theses.
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Flight statements electronic sensor.
Harant, Josef ; Fedra, Zbyněk (referee) ; Šebesta, Jiří (advisor)
This diploma thesis deals with theoretical analysis, design and practical solution of flight statements electronic sensor. This device is primarily intended for measuring telemetry data during aerobatic flights. Theoretical part contains fundamentals of GPS and inertial navigation systems. Design of the device is divided into three parts - design of block structure, construction and software for the measuring device. The final realization is made with respect to minimal system requirements and to possible future extensibility for wider usage spectrum.
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VHF-band antenna and low-noise amplifier
Bauer, Tomáš ; Šebesta, Jiří (referee) ; Kasal, Miroslav (advisor)
The contents of this thesis is a realization of a low noise amplifier for the band from 137MHz to 138MHz and a antenna for the recieving of the signal from NOAA satellites. The proper function of the low niose amplifier is verified by Ansoft Desinger simulation and the proper function of the antenna is verified by HFSS simulation. Both devices are realizated like prototypes and their parametres are measured.
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Wireless doorbell with digital voice transmission
Partsch, Patrik ; Šebesta, Jiří (referee) ; Mikulka, Jan (advisor)
The master´s thesis deals with a design and layout of wireless doorbell with digital voice transmission. It also includes the nRF9E5 circuit analysis. In the beginning of the document there is characterization of the problem in general. Next part describes a layout example for the application schematic, a layout of printed circuit board and a layout of software. nRF9E5 is a true single chip system with fully integrated RF transceiver, 8051 compatible microcontroller and a four input 10 bit AD converter. Despite of all studies of available literature I have found only very little particular information related to this matter. In general, the main aim of this work is to make the wireless doorbell with digital voice transmission. Further, ilustrated schematics are enclosed as a attachement of this thesis.
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Communication with external devices by I2C bus
Prax, Jakub ; Šebesta, Jiří (referee) ; Frýza, Tomáš (advisor)
This diploma paper deals with the data bus line I2C and a supportive demonstration tool for the subject Microprocessor technology taught at the Radioelectronics faculty. The data bus line I2C is convenient when short-distance data transmission with restricted spatial possibilities is required but high velocity of data transmission is not necessary. The tool is compiled in such a way that enables it to also perform other tasks apart from those dealing with the I2C data bus line. The data bus line in the tool is utilized for transmission of date, time, temperature, data for the D/A converter, data from and to the EEPROM memory and data to 16 bits expander.
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Medium Power LCC Resonant Converter
Petrásek, Radek ; Dřínovský, Jiří (referee) ; Šebesta, Jiří (advisor)
The aim of this diploma thesis is to study the resonant converters operation. This paper is concretely specialized to design and implementation the LLC resonant converter with output power about 350 watts. LLC resonant converter is prospective solution for similar applications. The general advantages are that the power MOSFETs are working on zero voltage switching condition, which reduce the switching loss and improve EMI performance. The detailed design for the LLC resonant tank characteristics presented in this paper, which fully guarantees the ZVS condition. This study is based on replacing the rectifier and load by an equivalent resistance applies the first harmonics approximation and the assumption that the current trough the diodes of the output rectifier has a sinusoidal waveform.
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