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Portable music player
Rozsíval, Adam ; Šotner, Roman (referee) ; Dřínovský, Jiří (advisor)
The thesis deals with the project of a portable music player with an amplifier in the class D. The device is powered up by connected power supply unit, eventually by built-in accumulator. Audio signal is played by bluetooth module, sound card or headphone output. Switching inputs and power supply of the accumulator is managed by a micro-controller. A correction equalizer for sound control is also embedded in the booster. All peripheries are put into a wooden baffle board. The sound is reproduced by a pair of loudspeakers.
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Design of class-D audio power amplifier
Fiala, Roman ; Götthans, Tomáš (referee) ; Brančík, Lubomír (advisor)
This semestral thesis describes class D low frequency power amplifiers and design of specific 2x100W class D power amplifier. The designed amplifier contains a second order sigma-delta modulator in which the quantization is controlled only by the delay of modulator components. This design does not include the clock generator which usually controls the quantization in sigma-delta modulators. This semestral thesis also includes design of a switched-mode power supply for the power amplifier and for the preamplifier. The PSpice program has been used for the design and verification of some sections of circuits. All designs have been built. Also basic parameters of completed circuits were measured.
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LNA for the APT signals receiver
Žúrek, Dan ; Urbanec, Tomáš (referee) ; Baran, Ondřej (advisor)
This bachelor thesis is dealing with design, realization and optimization of the LNA (Lownoise amplifier) for receiving of APT signals from the NOAA weather satellites in 137 MHz – 138 MHz frequency band. The first part of this work is aimed on critical parameters of the amplifier and the filter circuits especially on a noise figure and a high selectivity. The next part of this project is about the particular concept and simulation of LNA by using the Ansoft Designer software. The printed circuit board is realized in the Cadsoft Eagle. The final part of this bachelor thesis is dealing with a production of such amplifier together with its measurement and testing in a real operation of receiving APT signals.
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2x400W/8 ohms end amplifier
Káňa, Lukáš ; Balík, Miroslav (referee) ; Káňa, Ladislav (advisor)
Submitted text deals with a power amplifier intended for usage in music electronics. First part is related to the common problems of low-frequency amplifiers including principles and individual circuit wiring types. Next part is related to description of self-made power amplifier including wiring scheme diagram. The end of the text concerns about mechanical construction of mounting box and design of possible module layout inside a device.
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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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Design and implementation of interconnection tools for noise generator
Pokorný, Jiří ; Kubánek, David (referee) ; Krajsa, Ondřej (advisor)
The bachelor’s thesis explores the way of implementation of interconnection of LFTX Daughterboard 0-30 MHz Tx and LFRX Daughterboard 0-30 MHz Rx cards from Ettus research and cards from Spectrum Digital. In the first part of the thesis the design of two tools for two way transmission is shown. The paper contains everything from the basic findings through parts selection nad simulations to the final production and testing of the tools. In the second part a way of controlling similar tool through USB is explored.
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Computer design of the small CATV
Sedláček, Jan ; Slanina, Martin (referee) ; Říčný, Václav (advisor)
Main task of this bachelor’s thesis is to create an interactive automatic programme for designing circuits of individual or small common television aerial. The first part of this document describes main conceptions distribution of television signals, parameters of coaxial cable and also some kinds of signals distortion. There are described some important mathematics formulas used for calculation of coaxial cable attenuation and carrier to noise distance important for computing function of programme. The second part describes a procedure of designing of television cable circuit of individual or small common television aerial and includes prototypal calculation of two real circuits and its comparison with results of computer calculation by which correct function of programme is verified. A part of this document is also made by detailed description of programme and its functions. Source code of created programme is included in the end of this document.
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Digitally controlled filter
Rez, Jan ; Szabó, Zoltán (referee) ; Friedl, Martin (advisor)
This bachelor's thesis deals with design of a functional prototype universal digitally controlled analog frequency filter 2th order. Part of the design is the selection of appropriate filter topology diagram and selection of an integrated circuit. Universal filter will contain lowpass, highpass, bandpass and notch filter. The filter is tuned in cutoff frequency from 100 Hz to 15 kHz. The bachelor's thesis focuses on the circuit analysis of selected concrete structure of universal filter and possibilities of digital control filters. The practical part of this thesis includes PCB design, control software for filter and graphical representation of measured results.
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Development of wireless rumen probe
Šídlová, Ludmila ; Matěj, Zdeněk (referee) ; Fedra, Zbyněk (advisor)
The aim was to study the possibilities of wireless transmission from the stomach of ruminants and to design and implement wireless ruminal probe. The first part deals with the internal wireless probe. The next section describes and evaluates available ruminal probe. There is given its own equipment design in the other chapters. The probe was designed for power management and for working with harvestable ambient power. The frequency of 125 kHz with bipolar coding was chosen for wireless data transmission. Two air coils are used on both sides as antennas. The proposed probe was designed and wireless data transmission was tested.
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Design of audio power amplifier with Bluetooth connectivity
Bartoň, Jan ; Šotner, Roman (referee) ; Brančík, Lubomír (advisor)
This bachelor‘s thesis deals with the task of designing an audio amplifier, operating in class D, with a nominal output power of 2 x 80 W with Bluetooth connectivity, supplemented by an equalizer and a state display. A power supply and a user interface are designed as well. At first, research regarding audio amplifiers is made, followed by a more thorough description of class D operating principles. Afterwards the actual synthesis of the desired amplifier is presented, followed by the power supply design procedure. The correctness of the synthesis is later verified by simulations in PSpice and LTSpice. Theoretical design is then practically built, and its parameters are confronted with expected values by measurements.
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