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Photoimpedace spectroscopy characterization of optical and electrical properties of the photovoltaic cells
Mocharová, Zuzana ; Chladil, Ladislav (referee) ; Novák, Vítězslav (advisor)
Diploma thesis mainly describes the theoretical knowledge of the topic photoimpedance spectroscopy characterization of optical and electrical properties of the photovoltaic cells, which contains development and princip of cells working, material properties of photovoltaic cells, explanation of electromagnetic waves, spectrophotometry and impedance spectroscopy, followed by a discription of the measuring device and used measuring methods. The experimental section for each measurement method describes the steps of setting the program, then the tables with measured values are involeved in some parts and a part of each method are summary graphs of measured values with subsequent evaluation.
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Tone and Chord Recognition as an Android Application
Kucharovič, Oliver ; Černocký, Jan (referee) ; Szőke, Igor (advisor)
The aim of this work is to recognize tones and chords on any musical instrument using the microphone on Android mobile devices. The app scans or records the sounds which are analyzed. It writes to a visual representation which is similar to the musical notation. The work describes the problems of recognition and the solution of the problem using fast Fourier transformation and analysis of the spectrum of volumes. Work describes the theory of music and the training of individual tones. The application was subjected to user tests and recognition accuracy tests. The conclusion includes tests results and statistics from the Google Play publication.
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Acoustic emissions of buildings
Smažinka, Josef ; Uher, Pavel (referee) ; Rubinová, Olga (advisor)
The diploma thesis deals with acoustics with the main focus on acoustic emissions of buildings. The first part of the thesis aims to familiarize the reader with the field of acoustics as a whole. They will learn the basic concepts, quantities and relations that exist in acoustics. In the second part I focus specifically on the sources of noise in buildings and their surroundings, how can excessive noise affect health, what standards must be met and how to prevent excessive noise. The last part is devoted to practical measurements in the field, which is focused on real sources of noise in the city of Brno. The aim of this measurement is to compare the noise generated by buildings with other noises in the urban environment.
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Simulator of typical rotational machinery components faults
Vaľko, Matej ; Beneš, Petr (referee) ; Čala, Martin (advisor)
The objective of this thesis is to create a library in programming environment LabVIEW by company National Instruments, which objective is to simulate vibrations of different mechanical components, such as shaft, rolling element bearings, plain gearing and planetary gearbox in different circumstances and failures. The theoretical part contains information about typical failures of this mechanical components and their typical failure frequencies obtained from literature. In the description of theoretical part is inscripted simulator with user interface in already mentioned programming environment LabVIEW. Result of this thesis is library, which images time course of vibrations and spectral analysis for diffrent components with their respective failures.
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Disposal of Biotic Pests by EMW Radiation
Sobotka, Jindřich ; Klečka,, Tomáš (referee) ; Myslín, Jiří (referee) ; Tomíček,, Oldřich (referee) ; Šuhajda, Karel (advisor)
The possibility of using high-frequency electromagnetic radiation in the construction sector is a common knowledge. Various experiments have been carried out to dry construction materials, or even to destroy biotic pests. However, the majority of these experiments have been executed in laboratory conditions. It means they have been carried out under exact limiting conditions, often very far off those conditions in real building practice. Therefore, this dissertation aims at exploring the possibility of utilizing microwave technology in drying and heating of construction materials, in disposing of biotic pests and sterilizing building materials under real conditions in building practice. The thesis will explain that microwaves are a term given to a part of electromagnetic radiation. Electromagnetic radiation is based on the principle that the radiated energy is absorbed by water molecules present in moist building material. In the mass of the irradiated material, the radiated energy is transformed into thermal energy, where a so-called “motion” of water molecules occurs with the energy then being transformed into kinetic energy. The microwave technology itself offers a very wide range of use, which can be easily achieved, thus making the technology available to use in the future. Part of the experiments and the necessary measurements, too, has been carried out on selected types of building materials in the premises of the Faculty of Civil Engineering of Brno University of Technology. They have been executed under conditions which most closely correspond to the conditions in real buildings. Part of the experiments and the necessary measurements were carried out on particular constructions, by the so-called in situ method. As stated in the conclusion of the dissertation, laboratory measurements and the in situ measurements differ considerably in some cases.
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Automatization of Analysis of Performance and Power Consumption
Rudolf, Tomáš ; Jaroš, Jiří (referee) ; Nikl, Vojtěch (advisor)
This thesis deals with increasing efficiency of supercomputers. Higher efficiency can be achieved by reducing frequency of processor if the algorithm does not slow down significantly. This thesis presents set of scripts designed to monitor consumption of processor along with scripts that visualize these measured values. It also allows easy control of processor frequency. The created solution gives user a capability to measure given algorithm efficiency and optimize computing power of specific computer exactly for the algorithm. Due to this work the user will be informed about whether it is advantageous to run his algorithm on one or other frequency of the processor.
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Field strength measurement
Novák, Tomáš ; Dřínovský, Jiří (referee) ; Nováček, Zdeněk (advisor)
This thesis is focused on problems of measurement of field intensity especially in short-wave zone of received frequencies. To measure the intensity of electric field, it is necessary to use a suitable antenna whose properties and characteristics/parametres meet best the requirements of this measurement. These requirements are analysed/discussed in the introductory part of this thesis. From these requirements resulted one specific solution which is applicable to this problems. This solution is frame antenna which meets /matches best the requirements of this measurement. Furthermore, a complete suggestion for the frame antenna as well as its calculations were discussed. From individually calculated results graphical functionalities were set together that provided the bases for selection of suitable parameters for frame antenna. Then these bases were verified with similar antenna that was available. In second part of this thesis we modified standard antenna modul RFT FMA11 so that there would be a possibility to use it with any selective microvoltmeter.
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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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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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Application possibilities of LNVGA programmable amplifier
Sobotka, Josef ; Hanák, Pavel (referee) ; Jeřábek, Jan (advisor)
This thesis deals with the theoretical description of the qualitative characteristics and parameters of some modern active elements, also discusses the theory of signal flow graphs at the level applicable for the following frequency filter design methods. The thesis is also generally discussed the issue with the circuit simulator PSpice modeling theory and voltage amplifiers on the basic 6-levels. The practical part of the work is divided into two parts. The first practical part is dedicated to design four levels of simulation model of components LNVGA element. The second practical part contains detailed theoretical proposals for three circuit structures implementing the frequency filters 2nd order (based on the basic structure of the OTA-C) using signal flow graphs with configuration options of Q and fm based on the parameters of active elements in the peripheral structure and their verification with prepared LNVGA model layers.
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