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Design of a measurement circuit for electrochemical cells cycling in SEM chamber
Tran, Quoc Bao ; Trochta, David (referee) ; Klvač, Ondřej (advisor)
This diploma thesis deals with the design of a measurement circuit consisting of two separate modules for measuring electric current in the order of nanoamperes (nA) for the in-situ analysis of lithium-ion cells in microscopic dimensions. The aim of this thesis is to build a prototype measurement circuit to solve the electromagnetic interference (EMI) problems associated with in-situ analysis and to perform subsequent testing of this circuit or modules. The diploma thesis is divided into two parts, namely a theoretical and an experimental part. In the theoretical part, research on electrochemical cells is described, where the focus is directed towards lithium-ion cells. The principle of the function of these cells is described and research on their degradation mechanisms has also been carried out. Furthermore, the testing methods of lithium-ion cells such as GCPL, OCV and CV have been described. In the theoretical part, the in-situ experiments already performed at Thermo Fisher Scientific Brno are described. One experiment consisted of assembling an electrochemical cell on a MEMS chip and the other experiment was performed using a micromanipulator as a current collector. Measured data were affected by electromagnetic interference. The practical part discusses the design of a measurement circuit that would theoretically solve the problems of measuring very small currents from an EMI perspective. It also describes how the measurement circuit was tested.
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An EMC Robust Precise Voltage Reference for Automotive Applications
Krolák, David ; Husák, Miroslav (referee) ; Psychalinos, Professor Costas (referee) ; Horský, Pavel (advisor)
Klíčovou součástí moderních integrovaných obvodů je napěťová reference, která funguje jako srdce analogových bloků poskytující stabilní napětí. Tato disertační práce zkoumá pokročilé metody pro snížení citlivosti nízko příkonových referencí na elektromagnetické interference (EMI) pro automobilová prostředí s širokým teplotním rozsahem. Citlivost na EMI je nežádoucí jev, který může způsobit poruchy elektronického systému. Elektromagnetické rušení se může snadno vázat do obvodu prostřednictvím kabelového svazku a desky s plošnými spoji. Práce poskytuje přehled literatury, návrhy výzkumu a výsledky, které se zaměřují na skryté efekty v napěťovém referenčním jádru, jako je vliv parazitní kapacity z kolektorů bipolárních tranzistorů do substrátu integrovaného obvodu a efekty použitého operačního zesilovače. Jsou uvedena a implementována doporučení pro zlepšení EMI odolnosti napěťové reference. Aby se prokázala platnost navrhovaných vylepšení, byly vyrobeny a změřeny testovací čipy s navrženými napěťovými referencemi v různých technologiích.
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Differential and Common Mode Conducted Emissions Measurement
Matýsek, Michal ; Soldán, Josef (referee) ; Dřínovský, Jiří (advisor)
This work deals with interfering signals and noises, possibilities of their measurement, their reduction and afterwards with design of LISN. The theoretical part analyzes formation of interfering signals, their types, with possible measuring instruments for each type of these signals and their properties. In framework of practical part LISN for long-term load of 5A, frequency range from 150 kHz to 30 MHz, with possibility to measure symmetrical and asymmetrical noise separately and also with possibility to switch to normal mode of LISN was developed. For better results LISN was realized as two stage LC filter.
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Measurement and analysis of audio-frequency differential disturbances in distribution systems
Doseděl, Tomáš ; Havránek, Zdeněk (referee) ; Drápela, Jiří (advisor)
This thesis deals with voltage disturbances in audio-frequency propagated in distribution networks. In the theoretical part, a creation and effect of these interferences are discussed as well as current methods of their measurement. In the practical part of the thesis, a measurement device based on a frequency filter was developed. This measurement device is able to measure audio-frequency disturbances up to 250kHz without suppresion of audio-frequency disturbances. The maximum frequency on the output is limited by either 125kHz or 250 kHz filter.
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Optimum layout of workplaces security checks of passengers
Bordovský, Lukáš ; Janík, Radomír (referee) ; Šplíchal, Miroslav (advisor)
The final master’s thesis analyzes the individual elements of Security control workplace and solves their optimization with respect to the rulemaking side of things, and integration into the existing space layout with a vision of the increasing demand for transport. Solves the issue of electromagnetic interference elimination in the detection equipment and suggests possible solutions to overcome them. The work is primarily related to the Prague - Ruzyne airport.
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Coupling mechanisms of transmission interference
Chromý, Stanislav ; Vedral,, Josef (referee) ; Havlíková, Marie (advisor)
The primary focus of the Bachelor's Thesis is placed on description of dominant interference sources and coupling mechanisms of interference signals transmission from the source of interference into influenced system including main principles of minimization and elimination of interference impact on a system. A relevant part of the Bachelor's Thesis describes coupling mechanisms of interference signal transmission into a real cable system including derivation of theoretical coupling mechanism transmission and its subsequent verification by means of simulated non-harmonic signal measurement.
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EMD instruments and electromagnetic mmunity
Mikula, Dalibor ; Buchta,, zdeněk (referee) ; Havlíková, Marie (advisor)
The work deals with implantable devices and possibilities of interference of elektromagnetic field. At first, the electromagnetic compatibility is discussed. Basic terms are explained, followed by insisting on resources of possible distrurbing of implantable devices and standards dealing with this issue. Furthermore, short chapter about devices affecting function of implantable devices is introduced. It means devices which patients with implantable devices may meet in common life, as well as devices used in common life, also devices used jn medical environment. In the next part, measuring process of electromamagnetic effect in working compartment of FN Brno magnetotheraphy and elektrotheraphy is devised. There is a concept of measuring card thanks to which impulses of implantable devices are measured. Finally, a description of measuring on implantable devices in FN Brno. MIKULA, D. EMD instruments and electromagnetic immunity. Brno, 2009. 74 s. Master’s thesis in Brno University of technology on faculty of elektrical engeenerig and communication. Supervisor Ing. Marie Havlíková , Ph.D.
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Pacemakers and electromagnetic interference
Lojková, Lea ; Sekora, Jiří (referee) ; Havlíková, Marie (advisor)
This work is focused on cardiac pacemakers and sources of electronic interference. The project partly follows another thesis made in the same field of interest (Ing. Kulík, Dept. of Control, Measurement and Instrumentation) and uses similar methodics of measurement. In the theoretical part of the work, the principles of nuclear magnetic resonance and magnetic resonance imaging are briefly explained and most common methods used in MRI are described, as well as the definition of a cardiac pacemaker, main events in pacemaker history and development. Cardiac pacemaker as a system is described in more detail, including construction, control, most common sensors and the ways of use. Electromagnetic interference of cardiac pacemakers and implantable cardioverter defibrillators is processed via a complete review since the oldest scientific paper from December 1991 till May 2009. In the second part, measuring of magnetic field is described, as well as the possibilities of monitoring of its effects on cardiac pacemakers. In fact, there are two possible ways of measuring. off-line exposition of the sample to the magnetic field followed by data acquisition via pacemaker programmer or the continuous on-line monitoring of the pacemaker activity by the means of measuring PC card. While the first method is reliable in cases where the is no sign of malfunction and makes the experiments with a dynamic exposition of sample possible, in some cases it detects a virtual malfunction also in cases where in reality the devices works perfectly. The second method enables a reliable continuous monitoring of pacemaker activity during the whole experiment and its only problem is a higher level of signal noise caused by the sample movement.
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Electromagnetic field scanner and its utilization in EMC measurement
Chupáč, Michal ; Číž, Radim (referee) ; Kubánek, David (advisor)
Master’s thesis is focused on making the acquaintance of EMC issues and ways of electromagnetic field scanner RS321 utilization for pre-compliance measurements. First part contains analysis of available equipment’s influence on measurement results on the basis of gathered specification. Next part includes an example measurement used as operational manual for scanner and its controlling program. The most important part is correction evaluation for performed EMI measurement of signal generator using its EMC certification protocol and application of gained correction curve on independent EMI measurement of device tested by EMC testing laboratory. Other possibilities of scanner utilization are mentioned in the next chapters. Last part of the thesis contains suitability evaluation of EMC scanner on the basis of findings from performed measurements.
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Influence of magnetic and electromagnetic fields on signals transmitted by optical fibres
Schneider, Tibor ; Vrba, Kamil (referee) ; Münster, Petr (advisor)
The diploma thesis deals with the influence of magnetic and electromagnetic fields on signals transmitted by optical fibers. Subsequently, the results of individual measured values are evaluated and analyzed, which were measured using an interferometer and a polarimeter. The first part deals with the theoretical analysis of the principles of interference and polarization of light. It further explains the basic operation of the above-mentioned devices as well as the immunity of the optical fiber to EMI. The second part of the work presents selected devices and technologies that were used as a source of electromagnetic or magnetic radiation. Subsequently, individual phenomena are plotted both in the course of time and with the help of a spectrogram or Poincaré sphere. From the measured results we can conclude that the commonly available technologies, which were selected for the diploma thesis, will not cause greater negative problems to the signal on measured frequencies in optical fibre, that could degrade the transmitted signal.
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