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Tunable ARC frequency filter
Kufa, Martin ; Murina, Milan (referee) ; Sedláček, Jiří (advisor)
This bachelor thesis deals with ARC frequency tunable filters. The introductory chapter generally focuses on the basic terms of the frequency filters, such as the mathematical expression of the transfer function, types of selective filters, tolerant field, etc. The next section describes the actual higher-order ARC filters and cascade sequencing, especially ARC band reject and possibilities of its implementation. Following is a concrete realization of the ARC filter to band reject with suggestions for tuning the frequency components in the frequency range 10 kHz to 100 kHz and retuning quality factor. Finally, this work contains the printed circuit board (PCB) design of the ARC frequency analog and digital filter section for tuning F0 frequency and quality factor Q setting using digital potentiometers. Furthermore, it also outlines the flowchart of the program for digital control.
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Sources for electric fence
Surovec, Vojtěch ; Murina, Milan (referee) ; Steinbauer, Miloslav (advisor)
Bachelor’s project is divided to two parts. The First part is focused theoretically and the second part is focused practically. In the theoretically part we met the standartds of properties and application commercially avaible sources as well as of principle pulse (switch-mode) sources and circuit realization. In practically part is suggestion of circuit design and realization of source for electric fence, enebling becked up power 230 VAC / 12 VDC. The source have to contain control circuit for reliable function.
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Adaptive frequency filter
Dolák, Jan ; Murina, Milan (referee) ; Sedláček, Jiří (advisor)
This thesis deals with passive and active frequency filters and their realization. The mail goal of my thesis was to design, simulate and realize adaptive frequency filter with the possibility of alternating it's parameters. The designed filter should be an active band stop filter of fourth kind with the possibility of alternating it's resonance frequence f0 and it's coefficient of quality Q. At the beggining it was needed to study the theory of frequency filters, types of frequency filters, which are often used in praxis, their properties and ways of their realizations. Use of active filters with operational amplifiers was optimal possibility of their realization. Because of there was given them the biggest attention in this part of the thesis. Then it was searched the most acceptable solution of required band stop filter, witch would have the best properties. Digital potentiometers operated by microcontroller were chosen for setting different values of various parameters. Designed circuits were realized after the decision and adaptation of optimal wirings and then the programme for operating of microcontroller and digital potentiometers was configured. By this way designed circuits were experimentally measured.
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RESONANT AND QUASI-RESONANT SWITCHMODE POWER SUPLIES
Vašina, Petr ; Sedláček, Jiří (referee) ; Murina, Milan (advisor)
This project focuses on issues and solutions to switch mode power suplies. The first part discusses comparison of analog and switching power supply stabilized, and their essential involvement. Further addressed the concept of peripheral participation resonant switch mode power suplies. This chapter is progressively designed input circuit, the main part of the switching resources, output circuit and feedback circuit comparison. At the end of the project is the komplete wiring diagram with a list of used parts. Under the proposal was designed printed circuit, is characteristics were measured.
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Resonant and quasi-resonant converters
Krška, Vlastimil ; Sedláček, Jiří (referee) ; Murina, Milan (advisor)
Project is engaged in concept and realization of quasi – resonant converter with switching in minimum voltage which derive benefit from resonance capacitor and inductor. It is one of the possibilities how to increase efficiency of switch – mode power supply. While using resonant converters the losses are reduced, when the resonant inductor will connect and disconnect at zero current in inductor, or at zero voltage on inductor. Base of the power supply is chip NCP1337. Concept comes from detailed analysis functions of integrated curcuit and others curcuits of switch – mode power supply. Project includes a complete concept of all partial curcuits, description of a construction and the main parameters measured on the realized sample.
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Antialiasing frequency filter
Kocián, Daniel ; Murina, Milan (referee) ; Sedláček, Jiří (advisor)
The bachelor´s work deals with a project of the connecting of the antialiasing electronically turnable ARC filter of the low pass of the fifth order with the Butterworth approximation with the adjustable limited frequency FM in the extent 10 kHz – 100 kHz. The theoretical part includes a short summary and a description of constituent blocks of the complete device. Then the problems of the frequency filters are analyzed there. The practical part consists the project of the printed circuilts of all constituent blocks, then the calculation of all circuited components of ARC filter of the type of low pass for all limit frequencies of the filter. The result of the all work is a device which consists of five blocks and its core is the microcotroler ATmega16. For the electronic turnabling of the filter there are used digital potenciometers. The inseparable part is the enclosed CD-ROM which includes all made materials.
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SELV power sources
Friedl, Martin ; Murina, Milan (referee) ; Sedláček, Jiří (advisor)
The aim of this diploma paper is to examine the required characteristics of power sources SELV which are used for electric devices of category III. The first part of this diploma paper deals with general knowledge considering power sources. With the focus on switching power sources SELV, their overcurrent, thermal-overload and overvoltage protection and possible solutions of power sources SELV from the aspect of the required isolating safety. The second part of this work deals with the specific design of the power source SELV 230VAC/24VDC with the power output to 70W, with its implementation and with the measuring of its parameters.
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ARC filter for frequency analyser
Janečka, Martin ; Murina, Milan (referee) ; Sedláček, Jiří (advisor)
The aim of this work is to propose and realization an active frequency filter with a 4th grade bandpass for making it possible to electronically tune the resonant frequency in range of 10Hz to 100kHz and adjust bandwidth. The thesis discussed two possibilities of filter connections using cascade synthesis. To choose a better option a filter simulations were made in Pspice. Based on the simulations, the number of components and the possibility of electronic tuning a better option is selected. This circuit is implemented, measured and then compared with simulations.
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