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Narrow-band PLC modem
Skala, Milan ; Krajsa, Ondřej (referee) ; Mišurec, Jiří (advisor)
This bachelor's thesis deals with narrow band PLC modem for 230/400 V power line. In the first chapter we can find basic theory about using modulation, interference, impedance of line, communication, capacitive and inductive coupler. Next chapter deals with design and simulation of capacitive coupler, transceiver circuit, receiver circuit, power supply and circuit for modem synchronization with power line frequency. In this chapter we can find information about building a converter from UART to USB. Third chapter of this thesis is dedicated to designing the printed circuit board and building the modem. Last chapter deals with setting the modem switches, description of its inputs and outputs and basic manual for the modem's software.
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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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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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Two-channel nine-band equalizer
Kollár, Marcel ; Kolka, Zdeněk (referee) ; Petržela, Jiří (advisor)
The aim of this project has been making the acquaintance of the adjustment of the audio signal of the frequencies switches and the suggestion of the nine band analogue equalizer. The suggestion equalizer was simulating in the program PSpice. Make a printed circuit using Eagle software and construct equalizer also with excitation indicator. The best option for the implementation of the equalizer has seemed to apply of the band’s correctors with the series resonant circuit. Every band in the equalizer has the distinction with the definite resonant frequency f0 and with extent of the correction ±dB. This project points out some options of the adjustment of the audio signal with help frequencies correctors and filters.
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Frequency filters controlled via microprocessors
Bronec, David ; Kincl, Zdeněk (referee) ; Biolková, Viera (advisor)
This thesis is focused on the microprocessor-controlled frequency filter project. The main goal of the thesis is to present basic terms and principles of frequency filters and active frequency filters for cascading synthesis. Furthermore, the work contains information on digital potentiometers. The thesis includes circuit simulations and a project of connecting with a printed circuit board. The last chapter contains the results of the measurements.
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High-order frequency filters using modern active elements
Chrást, Jakub ; Minarčík, Martin (referee) ; Jeřábek, Jan (advisor)
The bachelor thesis deals with the designing of active frequency filters of the second – order which is useful for the construction of cascade high – order filters. These filters were designed by means of autonomous circuits. Multiple current mirror and inverter MCMI, current operational amplifier COA and current differencing transconductance amplifier CDTA were used as active elements. Designing is focused on the circuits using MCMI. Designed filters work in current mode. In the introductory part there are described general characters of frequency filters. The second part includes the methods of construction high – order filters, the third part contains the description of active elements used. The design we can find in the fourth part. The functionality of filters was verified by computer simulation. One of the optimal filters was practically verified by available component UCC 0520. Two other filters were used for the construction of the fourth – order filter.
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Innovation of the software for design of the analog frequency filters
Boleček, Libor ; Slanina, Martin (referee) ; Petržela, Jiří (advisor)
The object of this bachelor‘s project is to create a PC programme for designing crossbar filters. The programme is realized with programming language C++ and Borland C++. The application uses the method of designing filters which is based on the normalized lowpass filter. This method uses the application of normalized approximation. The user interface of the programme has a wizard character. Input data are parameters of filters which are ordered by a user. The user orders the marginal frequency and the type of filter. The output is an electrical circuit with RLC parts values. The user has a choice if he/she wants to realize the circuit as a T or type circuit. The output may be printed or saved to a file.
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Active Frequency Filters with Minimal Configuration
Preclík, Milan ; Jeřábek, Jan (referee) ; Koton, Jaroslav (advisor)
This work deals with exploitation of multiple current and voltage gates of active components. After that an optimal circuit´s scheme choice, its simulation and subsequent realization of frequency filter follow. First of all there is a common description of frequency filters and current and voltage conveyors. Furthermore the text focuses on searching circuit´s schemes of second-level frequency filters, described by characteristical equation. These equation make an easy numerical concept possible. New circuits with one active component and with a minimal number of pasive components are searched by using the method of autonomous circuits. The choice of resulting circuit based on simulations executed in Orcad is next in line. The work concludes with verification of a proper function of our filter.
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Analog frequency filter design using signal flow graphs
Petlák, Martin ; Vrba, Kamil (referee) ; Minarčík, Martin (advisor)
In my graduation thesis I first of all shortly mentioned frequency–selection filters and their utilisations. However, the base point of this project was to acquaint with different types of signal flow diagrams with whom I should design and analyse frequency-selection filtres with conventional and also innovative active components. As the first I created signal flow diagrams for both voltage and current conveyors. These modern active components are well known today and enable the construction of circuits with better properties than circuits with traditional differentiating amplifiers with voltage feedback. Thereinafter I made signal flow diagrams for OTA component. Transconductancal amplifiers are well known active components used in various areas of analog signal processing. OTA amplifier is in fact the current source controlled by voltage difference, which is characterised by gm transconductance. Ulterior components were IOZ and IZN models of voltage amplifier with voltage gain A. The last component was COA amplifier. It is a current operational amplifier. COA model is fully dual component to VOA, which is classical voltage amplifier. In my project I used filters with two OTA components. This filter offers functions like low-pass filter, band-pass filter, high-pass filter, band-stop filter and two-phase network. Following this I used circuits with two GCC conveyors. These offer band-pass filter, low-pass filter, high-pass filter, band-stop filter and two-phase network. Ultimately I designed filters with COA components, which offer three transmission functions simultaneously (DP, PP and HP). Analysis of these filters was made with a help of PSpice computer programme.
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