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Noise in the interior of vehicles and methods of reducing it
Patočka, Pavel ; Zajac, Roman (referee) ; Otipka, Václav (advisor)
The bachelor thesis focuses on the issues of noise in the interior of vehicles and the methods of subsequent decrease of such noise. Moreover, the thesis shortly describes the most notable sources of noise involved in the overall acoustic within the automobile. The undertaken analysis illustrates that the main source of noise in older vehicles is the combustion engine, an exhaust and intake system, and a gearbox tool. Conversely in modern vehicles, as a result of the unceasing progress of alternative drives, the most notable noise in modern vehicles is the aerodynamic noise and the noise forming out of the contact between tires and roadway. The research showcases that the elimination of these sources is aimed at the use of isolation and absorption structures, as well as the technologically advanced methods such as the ANC method. In relation to the increasing pressure on emission-free traffic, often resulting in insufficient vehicle soundproofing, the thesis summarises the findings concerning the issues of additional vehicle soundproofing.
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RLXY
Sedláček, Tomáš ; Suchánek, Jiří (referee) ; Krekovič, Slavomír (advisor)
The project is conceived as audiovisual performance using own author´s software. The project is focused on experiments with transfer of three-dimensional data, two-dimensional image into the sound and on the contrary. The goal of the project is to explore medium itself and to find new solutions.
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Power Line Communication - demonstration test bed
Jureková, Petra ; Fujdiak, Radek (referee) ; Mlýnek, Petr (advisor)
This thesis is focused on data communication through electrical power grid - PLC Power Line Communication (PLC). It describes PLC communication, its present possibilities and two main types of transmission - broadband and narrowband, which are compared in detail. Major topic is an impact of noise on PLC signal and effect of growing distance on transmission efficiency. Within that is processed the analysis of distance and noise influence. Practical part of the thesis contains many types of measurements focusing especially on broadband modems. Measurements were performed both in the home and in the laboratory environment. The results show the effect of the distance and interference on the network throughput and the spectral power of the PLC signal. The RFC2544 methodology was also used for measurements.
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Precision audio preamplifier for headset measurement
Šimek, Michal ; Balík, Miroslav (referee) ; Hanák, Pavel (advisor)
This thesis deals with microphone and headphone preamplifier for microtelephone and headset. The design shall meet the electrical interface requirements set out in ITU-T Rec. P.381(08/2012). The design includes a voltage converter, microtelephone bias and both a battery and an external power supply. In this work is also described the design of printed circuit board and the solution of a low noise in the whole circuit. The aim of this thesis is to design, built and embed the laboratory fixture into a metal box. Finally, measure the product on an APx525 audio precision analyzer.
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System for precise dynamic measurement of bridge sensors
Čech, Jonáš ; Kolka, Zdeněk (referee) ; Kubíček, Michal (advisor)
This master’s thesis deals with design of measurement system for dynamic measurement of bridge sensors. After a short theoretical part, the own concept is introduced. System can provide sampling rate up to 250 kSa/s with 24-bit resolution. The maximum number of samples is about one and a half milion. At first, the design of analog part was made, in this phase of design the digital part is based on evaluation board with ARM Cortex-M7 and external memory. After final choice of appropriate ICs, the analog and digital part will be integrated into one PCB.
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Noise Generator Diagnostics
Plucková, Iveta ; Nahodil, Petr (referee) ; Hammer, Miloš (advisor)
The bachelor thesis deals with noise diagnostics of the generator. The practical part of the thesis is realized in the Dukovany Nuclear Power Plant. The first part of the thesis, noise is generally discussed. The quantities and their measurements are described, quite generally, also for the given company. According to specific conditions in the Dukovany Nuclear Power Plant, there is a distribution of noise measurements, which is carried out by an external company. The work gives a concrete example of this measurement. At the end of the work, the practical measurements of noise were done for selected generators, which were realized by an author for the purposes of this bachelor thesis. The experiment is evaluated.
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Low - noise pavements
Mojžíš, Martin ; Zdřálek, Petr (referee) ; Hýzl, Petr (advisor)
Master´s thesis is interested in the problems of low-noise road surfaces. The theoretical part describes noise, sources of noise, the low-noise road surfaces and the practical part describes two proposals of low-noise stone mastic asphalt SMA 8 LA.
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ECG noise generator
Mikuláš, Karol ; Kozumplík, Jiří (referee) ; Hrubeš, Jan (advisor)
Real ECG signal contains undesirable artifacts arising from its capture. Due to loss of diagnostically useful information in the noise signal and followed by the filtering the signal is important to know the characteristics, the most common symptoms and causes, to avoid or minimize the noise ECG signal. ECG noise generator is an educational program designed to serve the learning methods of filtering the noise signal. The user program can verify the effectiveness of the chosen method and the extent of deformation of the useful signal. The program includes basic types of artifacts, such as powerline interference, baseline wander, drift, impulse noise, myopotentials and change of baseline wander of ECG signal, which can be prepared noise signal from a database or other signal selected by the user.
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Optimization of tomographic station GE phoenix adjustment for plastic components including metal parts
Starý, Přemysl ; Petrilak, Michal (referee) ; Zikmund, Tomáš (advisor)
X-ray computed tomography is a tool mostly used in a medical diagnosis. A development of the technique and an improvement an in accuracy of tomographic systems enabled an utilization of the tomography in industrial applications. The tomography allows non-destructive analysis of inner structure. There is a negative influence of a reconstructed area if a low-absorption and high-absorption materials are scanned together. This influence makes analysis of the inner structure impossible. There are two options to eliminate these artifacts. We can use algorithms to reduce metal artifacts, or we can try to avoid them when performing the scan. This bachelor thesis focuses on an optimization of tomographic station adjustment for the plastic components including metal parts. The effect of an usage of X-ray filter or collimator and effect of a sample orientation on data quality will be observed. We use tools like contrast, noise and edge sharpness to evaluate data quality.
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Noise, Transport and Structural Properties of High Energy Radiation Detectors Based on CdTe
Šik, Ondřej ; Lazar, Josef (referee) ; Navrátil, Vladislav (referee) ; Grmela, Lubomír (advisor)
Poptávka ze strany vesmírného výzkumu, zdravotnictví a bezpečnostního průmyslu způsobila v posledních letech zvýšený zájem o vývoj materiálů pro detekci a zobrazování vysokoenergetického záření. CdTe a jeho slitina CdZnTe. jsou polovodiče umožnují detekci záření o energiích v rozsahu 10 keV až 500 keV. Šířka zakázaného pásma u CdTe / CdZnTe je 1.46 -1.6 eV, což umožňuje produkci krystalů o vysoké rezistivitě (10^10-10^11 cm), která je dostačující pro použití CdTe / CdZnTe při pokojové teplotě. V mé práci byly zkoumány detektory CdTe/CdZnTe v různých stádiích jejich poruchovosti. Byly použity velmi kvalitní spektroskopické detektory, materiál s nižší rezistivitou a výraznou polarizací, detektory s asymetrií elektrických parametrů kontaktů a teplotně degenerované vzorky. Z výsledků analýzy nízkofrekvenčního šumu je patrný obecný závěr, že zvýšená koncentrace defektů způsobí změnu povahy původně monotónního spektra typu 1/f na spektrum s výrazným vlivem generačně-rekombinačních procesů. Další výrazná vlastnost degenerovaných detektorů a detektorů nižší kvality je nárůst spektrální hustoty šumu typu 1/f se vzrůstajícím napájecím napětí se směrnicí výrazně vyšší než 2. Strukturální a chemické analýzy poukázaly, že teplotní generace detektorů způsobuje difuzi kovu použitého při kontaktování a stopových prvků hlouběji do objemu krystalu. Část mé práce je věnována modifikaci povrchu svazkem argonových iontů a jejímu vlivu na chemické složení a morfologii povrchu.
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