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Adjustable timer for three-phase motor
Motyčka, Lukáš ; Petržela, Jiří (referee) ; Hruboš, Zdeněk (advisor)
The thesis describes several potential solutions of an adjustable timer, such as monostable multivibrators, asynchronous (ripple) and synchronous counters and microcontrollers. It also deals with issue of switching three-phase asynchronous motors with limit a high starting current on starting - star-delta switch, softstarter, frequency inverter. Particular attention is focused on the conceptual design of the timer using micro- controller Atmel (timer control unit), LCD (display device) and control switches. The microcontroller will be complemented by external 32,768 kHz watch crystal, necessary for real-time function - Real Time Counter (RTC). The cause for this choice is not only simplicity and clarity of control to the operator, but also reliability, low power consumption and also the price of the device itself.
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Analog Guitar Multieffect
Zapletal, Ondřej ; Petržela, Jiří (referee) ; Staněk, Miroslav (advisor)
Presented thesis is focused on guitar effects used for sound modification produced by an electric guitar. The main aim of this thesis is an introduction into guitar effects topic and the design of selected types chosen as follows: overdrive, noise gate and delay. Final multieffect is created by these mentioned components. Another part of presented thesis is the design of source feeding the whole final multieffect. Furthermore, the design of chosen components is presented in this thesis as well as the including of control simulations and PCBs.
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Design, simulation and measurement of active filters with modern functional blocks
Melša, Vojtěch ; Petržela, Jiří (referee) ; Brančík, Lubomír (advisor)
This work concentrates on the possibilities of how to connect electric filters with functional blocks. Then we choose the best possible connections and their characteristics are simulated in the Pspice program. From the comparison of the results of simulation, possibilities of tuning, quantity of functions, complicacy of connections and mainly by commercially available integrated circuits is chosen the connection which is realized in a laboratory preparation form. Its measured characteristics are compared with results of simulation
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Mutlifunctional electronically adjustable KHN filters
Harsa, Jan ; Petržela, Jiří (referee) ; Šotner, Roman (advisor)
In the bachelor thesis some types of KHN filters are analyzed and presented. Filters contain various active elements and they works in the current, voltage and hybrid mode. Great attention is paid to the so-called diamond transistor, which may represent different functional blocks (amplifier with current feedback link, transconductance amplifier and current conveyor) in these circuits. Attention is also paid to the possibility of tuning the filter, which consists in changing the characteristic frequency and quality factor independently. Tuning is achieved by using electronically tuneable active blocks such as voltage controlled operational amplifiers or analogue multipliers. Adjustability is also realized by tuneable passive components (potentiometers). Circuits are tested using the simulation program PSpice. Simulations are performed with professional macromodels, such as model OPA860 or VCA610 (Texas Instruments). In the thesis are results for sensitivity and tolerance analysis, which were gotten with third-level models. The optimization is also resolve for parameters of tuneable filters. The characteristics of the filter operating in voltage mode were verified by measurement.
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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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Diode shaping circuit examples for educational purposes
Kasatkin, Alexey ; Petržela, Jiří (referee) ; Šotner, Roman (advisor)
Tato bakalářská práce je věnována návrhu a realizaci diodového obvodu tvarovače a diodových omezovačů obou polarity s různými zapojeními pro laboratorní. Prvním z nich je tří segmentový obvod tvarovače s aktivním prvkem (operačním zesilovačem). Obvod převádí trojúhelníkový signál na harmonický signál. Druhým obvodem je vykrajovač s proudovým sledovačem, který signál na výstupu odřízne. Třetí je jednoduchý omezovač s nezávislým nastavením úrovně omezení. Cílem konstrukce bylo dosáhnout co nejmenšího zkreslení signálu na výstupu. Funkčnost obvodů byla ověřena simulací a měřením.
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Synthesis of higher order passive RLC filters for educational laboratory purposes
Černý, Marek ; Petržela, Jiří (referee) ; Rujzl, Miroslav (advisor)
This bachelor thesis deals with the Synthesis of higher order passive RLC filters. The main target was to design a set of filters for educational laboratory purposes, which will contain filters of different orders and approximations (Chebyshev, Inverse Chebyshev and Cauer). The filters were designed according to design tables for standardized lowpass filters and were subsequently simulated in the PSpice program (Frequency analysis, Monte Carlo, Worst Case). Subsequently, a laboratory preparation was designed and revived. Individual filters were tested and compared with ideal waveforms.
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Laboratory task dedicated to filters with switched capacitors
Khaibullin, Rishat ; Šotner, Roman (referee) ; Petržela, Jiří (advisor)
This thesis describes the basic principles of circuits based on switched capacitor technology. The advantages of using this technology are described, and the different connection types of switched capacitors are shown. A graphic comparison of the operation of classic analog filters and filters based on switched capacitor technology is also provided. A solution for the implementation of a laboratory board for use in education is offered. The board has been successfully tested, and an example of a laboratory problem solution is given.
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Phase shifted harmonic oscillators for practical education
Hudec, Marek ; Petržela, Jiří (referee) ; Šotner, Roman (advisor)
This thesis focuses on designing a laboratory preparation for the study of phase-shift oscillators. The first part of the thesis comprises a theoretical discussion regarding the given problem. The laboratory preparation will include two types of oscillator circuits. An operational amplifier will be used as the amplifying element together with an RC feedback loop in one type of circuit whilst the other type will consist of operational transconductance amplifier employed as inverting amplifiers and generating feedback. The second part of the thesis includes the actual design of the preparation. The design process covers construction stage of the preparation, calculation of the component parameters necessary for oscillation to occur, simulations of the individual circuits along with THD analysis as well as with analysis of manufacturing variances. The second part of the thesis also contains the design of a separate block of all-pass filter. The simulation results will be verified experimentally, on a printed circuit board. In the last part of the thesis, I will evaluate and intercompare the theoretical, simulation and practical results.
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Phase shifted harmonic oscillators for practical education
Hudec, Marek ; Petržela, Jiří (referee) ; Šotner, Roman (advisor)
This thesis focuses on designing a laboratory preparation for the study of phase-shift oscillators. The first part of the thesis comprises a theoretical discussion regarding the given problem. The laboratory preparation will include two types of oscillator circuits. An operational amplifier will be used as the amplifying element together with an RC feedback loop in one type of circuit whilst the other type will consist of operational transconductance amplifier employed as inverting amplifiers and generating feedback. The second part of the thesis includes the actual design of the preparation. The design process covers construction stage of the preparation, calculation of the component parameters necessary for oscillation to occur, simulations of the individual circuits along with THD analysis as well as with analysis of manufacturing variances. The second part of the thesis also contains the design of a separate block of all-pass filter. The simulation results will be verified experimentally, on a printed circuit board. In the last part of the thesis, I will evaluate and intercompare the theoretical, simulation and practical results.
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