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Synthesis of circuit element with fractal dynamics
Domanský, Ondřej ; Hruboš, Zdeněk (referee) ; Petržela, Jiří (advisor)
The first aim of this diploma thesis is to clarify problems with circuit elements described by the fractional-order dynamics, show their basic properties and possible applications in circuits with lumped parameters. The second topic is covering the synthesis of two-terminal devices which have different fractional-orders for requested phase shifts. For this kind of devices, the thesis also describes their optimization and approximation in the frequency domain and subsequent implementation in the form of passive ladder structures. The final part of diploma work will be focused on practical realization of universal fractional PID controller and the verification of proper function of this multi-port in various configurations to prove its correct function via real measurement of frequency and time responses.
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Power-supply generating specified current pulses
Svoboda, Karel ; Petržela, Jiří (referee) ; Šotner, Roman (advisor)
This bachelor’s thesis deals with generation of current impulses, which can be defined in range of few ampers, to resistive load. The first part of this project is focused on analysing of single circuit´s concepts and posibility of theirs analog control. The next part of this work describes whole setup of designed circuit. This thesis includes simulations from PSpice and signal snapshots from an oscilloscope, which prove the functionality and parameters of the whole device. Final section of this work discuss all results achieved during design proces.
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Guitar electron-tube amplifier
Kokolia, Martin ; Petržela, Jiří (referee) ; Kratochvíl, Tomáš (advisor)
The objective of this bachelor’s thesis was to design a low-frequency tube amplifier optimized for use with electric guitar. The preamp is equipped with ECC83 triode tubes as voltage amplifier and cathode follower for connection with a simple frequency corrector. The output of the FX loop allows the connection of external effects. The power amplifier is realized by dual-action 6L6 tubes and phase invertor with ECC81 triode. Output transformer allows impedance matching for speakers. The power supply uses a GZ34 rectifier tube and diode bridges. Text of thesis also includes theoretical design of guitar tube amplifier and documentation of realization of functional prototype.
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Audio signal transfer using wireless technologies
Gasnárek, Jiří ; Vochyán, Josef (referee) ; Petržela, Jiří (advisor)
Description of construction of analog-to-digital and digital-to-analog convertors for audio signal and distribution via wireless channel, are the objectives of my master's thesis. There are descriptions of DPS construction, design of panels and measurement of system parameters in the project, above all sampling and reconstruction of audio signal, power consumption and signal range of wireless modules. At the end is discussed real usage and suggestions for further developement.
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FM receiver with RDS-TMC decoder
Štohanzl, Milan ; Petržela, Jiří (referee) ; Prokopec, Jan (advisor)
The system RDS is dedicated to broadcast an additional information for VKV transceivers. This bachelor work is concerned with a construction and a description of FM receiver with RDS data decoder. The document disserts on concrete connection of a circuit and describes programs for microcontroler and computer. Further it shows possibilities of corrections of particular components of the receiver and the programs.
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AC/DC adjustable power converter 5 - 30 V / 30 A
Matýsek, Michal ; Brančík, Lubomír (referee) ; Petržela, Jiří (advisor)
This work deals with the switched mode power supplies, their possible solutions and consequently with design of a power source with given parameters. The theoretical part analyses behaviour of the switched mode power supplies. Further it contains a survey of wiring of AC/DC converters and their properties. In the framework of the practical part was developer the power AC/DC switching power supply with adjustable output voltage from 5 to 30 V and 30 A current. The source was designed as a half-bridge decreasing converter with a transformer.
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Analysis of the electronic circuits using Mathcad program
Šimůnek, Martin ; Vochyán, Josef (referee) ; Petržela, Jiří (advisor)
The main idea of this thesis is a propose by designing filters in Mathcad program. This paper deals with a basic principle in filters design and these principles are implemented into the Mathcad program. In the introductory part is described aproximation which was used in Mathcad script. In the other parts of this project is described program which was created on designed filters.
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Study of Electronic Control and Real Behavior in Variable Filtering and Oscillating Applications of Modern Active Elements
Šotner, Roman ; Ondráček, Oldřich (referee) ; Martínek,, Pravoslav (referee) ; Petržela, Jiří (advisor)
The thesis deals with electronically adjustable and configurable applications of the modern active elements. In the field there were presented various active elements in applications of the analog filters and oscillators which stem from basic and more or less similar principles of circuit synthesis and design. However, there is not provided study of real behavior in detail and in most cases electronic control of the various parameters in application is not verified. In the precise design of application is very important to identify problematic features and determine how much it influences functionality of the device. In this work several filtering structures based on common and modified synthesis principles (integrator loops) are compared in the view of multifunctionality, configurability, variability, kind of used electronic control and impact of influences of real elements on behavior. There are used standard methods like adjusting of variable transconductance, intrinsic value of current input resistance and not so common method based on variable current gain in design of modified and improved multifunctional filtering circuits. The last method of mentioned control enabled to find quite unique filter which allows continuous electronic change of transfer from band-reject to all-pass filter of the 2nd order without reconnection. It is much simpler than previous and more common integrator loops. Larger part of this work is focused on electronically controllable oscillators mainly on quadrature types. There is presented several very simply and elementary realizations which require minimal number of active and passive elements. There are also slightly or more complicated solutions which remove some drawbacks of mentioned simpler variants. First of all there is given attention on study of real behavior which make obvious different problems with mutual dependence of oscillation condition and oscillation frequency, dependence of produced amplitudes (quadrature types) on parameter which is controlling oscillation frequency, influence of this parameter on oscillation condition, etc. In the framework of this part of the thesis there was introduced a novel modification of current conveyor transconductance amplifier (CCTA) so called current-gain-controlled current conveyor transconductance amplifier (CGCCCTA). Requirements for novel applications in the field of oscillators for newly developed controllable current amplifier and digitally controllable current amplifier (DACA) at the Department of Telecommunication FEEC BUT lead to creation of several chapters of this work where mentioned active elements can be used. The important contribution of this work (for practical approach) is also experimental testing of most of designed circuits and determination of exact design equations and rules which take into account real behavior of circuits and confirm results obtained from experiments.
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Electronically controlled active 2-nd order filter
Ševčík, Břetislav ; Petržela, Jiří (referee) ; Šotner, Roman (advisor)
The diploma thesis deals with the modern design of the control circuits for digital potentiometers and their application in analog systems. The concept of the digital control is demonstrated on the electronically controlled active 2-nd order filter and programmable oscillator. The proposed design of the active filter describes a programmable active 2-nd order filter Sallen-Key. In this circuit it is possible independently programme cut-off frequency, Q factor and type of approximation with very good accuracy. The circuits of the designed filter and designed oscillator are simulated in PSpice (OrCAD), parasite effects and effects of the real parts are studied. Properties simulated circuits are compare with experimental results. These results appreciate quality and efficiency of the digitally controlled potentiometers in dependence on variable input circuit parameters. Integral part of this project is author’s universal control program called Digipot and comunications interface for many types of digital potentiometers with I2C, SPI or Up/Down interface. It is possible to use this device for many applications. The constructional details of the filter are presented at the end of this work. The software equipment is availability on enclosed CD.
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Audio amplifier working in class AB with 400W output power
Kopic, Jan ; Šotner, Roman (referee) ; Petržela, Jiří (advisor)
The content of the thesis is the theory related to low-frequency audio amplifiers that is summarized in a separate chapter. This section describes the division of these amplifiers according to various criteria, as well as their working classes and parameters that determine their behavior. In addition, this thesis contains a description of the principle of the function of the selected class AB amplifier, which is divided into individual functional blocks and completed by the addition of speaker protection circuit. Criteria of selection for important chosen components are mentioned in appropriate chapters and supplemented with data from components datasheets. The output results of the simulations are always commented and compared with the calculated values at the end of the relevant chapter. The attachment of the thesis contains PCB design for the device realization. The correct operation of build device has been verified and measured.
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