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Fiber Optic Michelson Interferometer
Dorazin, David
The aim of this paper is to theoretically desribe function of the Optic fiber Michelson interferometer and its parts with description of the most important issues which can occure due to bad design. Second part of this paper is dedicated to simulation of the optic fiber Michelson interefometer in professional simulation software VPIphotonics.
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Coexistence of LoRa and Wi-Fi in the RF band 2.4 GHz
Kaučiarik, Filip ; Miloš, Jiří (referee) ; Polák, Ladislav (advisor)
Diplomová práca sa zaoberá štúdiom koexistencie, ktorá môže nastať medzi bezdrôtovými komunikačnými systémami LoRa a Wi-Fi v bezlicenčnom ISM pásme 2,4 GHz. V teoretickej časti práce sú stručne popísané fyzické vrstvy obidvoch systémov. Následne sú definované spoločné frekvenčné pásma a koexistenčné scenáre, ktoré môžu vzniknúť medzi uvažovanými systémami v spoločnom rádiofrekvenčnom (RF) pásme. V experimentálnej časti práce je prezentované laboratórne meracie pracovisko, ktoré bolo navrhnuté na meranie rôznych koexistenčných scenárov medzi technológiou LoRa a Wi-Fi. Funkčnosť navrhnutej koncepcie je overená experimentálnym meraním. Výsledky meraní sú detailne komentované a prezentované. Je navrhnutá laboratórna úloha a vzorový protokol pre vzdelávacie účely v Laboratóriu Mobilných a Bezdrôtových komunikácií.
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Michelson's interferometer
Rýc, Jan ; Klusáček, Stanislav (referee) ; Havránek, Zdeněk (advisor)
The diploma work deals with techniques of optical contactless distance and velocity measurement. A basic summary of the methods are involved. The problematic of interferometric methods for vibration measurements is analysed in detail. It contains division of interferometers, description of their function principles and also chapters dealing with elements used in interferometers such as lasers, photodetectors and elements in the ray optical way - polarizers, retarders, optical isolators. The vibration and length measurement methods are described, as well as the conception of homodyne and heterodyne detection. Part of this work focuses on the quadrature signal processing and on the proposal of algorithm for demodulation of velocity/displacement and undergoing simple motioning object deviation. This algorithm is implemented in Labview and the whole software instrument served also for visualisation of measured data of the interferometer model constructed in the laboratory. The way how to build up a model, its setting and two possible configurations suitable for homodyne detection are described. Model of interferometer is built-up on the optical breadboard. Particular components are fixed by the help of mounts. The model and software enable to measure the velocity and the vibration deviation with the light wavelength exactness. Functionality and the exactness of the laboratory model are verified by vibrometer. Effects on the measurement uncertainty are discussed here and ways how to restrain them are proposed.
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Electromagnetic interference and pacemakers
Kulík, Jindřich ; Richter, Miloslav (referee) ; Havlíková, Marie (advisor)
This thesis deals with electromagnetic compatibility of implantable electro-medical devices using in cardiology. The main aim of this thesis is detection of the resistance of implantable pacemakers (PM) and implantable cardioverter defibrillators (ICD) to the electromagnetic interference. In the first part of this thesis, a function of the heart, which is necessary for understanding of PM and ICD operation, is described. The function and construction of PM and ICD is detailed in the theoretical part as well. The next part is focused on the electromagnetic compatibility. The next part is description of the measurement method and the experimental arrangement used for practical experiments with electromagnetic resistance of PM and ICD.
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Radio Access Network of a Cellular Network
Duda, Michal ; Novotný, Vít (referee) ; Krkoš, Radko (advisor)
The aim of the work is the radio access network of mobile networks second, third and fourth generation. The main objective is a description of the radio access network of the second, third and fourth generation, their elements, interfaces and signaling procedures. The next part describes the emergency services and the architecture of the fourth generation mobile networks. The practical part is then devoted to identify actions needed to prepare radio access network to testing emergency services, identify actions needed to conversion of transport protocol fixed part of the radio access network from IPv4 to IPv6 and describe the intervention to radio access network to change the active segment of the core network.
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Web applications supporting education of audio signal processing
Malcher, Tomáš ; Mokrý, Ondřej (referee) ; Rajmic, Pavel (advisor)
This bachelors thesis deals with a creation of web applications using JavaScript language. These web applications should be helpful in signal processing classes by showing and explaining different phenomenons to students. Students can see how different parameters affect the outcome of said issue. The theory needed for understanding and implementation is covered by this thesis. Thesis covers key parts of the code of said web applications and the libraries used for their implementaition.
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Optical signal detection and maesurement of low deflections using the Michelson interferometer
Kováč, Petr ; Hudcová, Lucie (referee) ; Křivák, Petr (advisor)
The dissertation is concerned with the description and utilization of interference of two coherent optical rays. In addition, the conditions of coherence and its connections with the occurance of interference are discussed. Michelson's interferometer is used for the practical utilization of the interference effect. The possibility of measuring relatively small changes is demonstrated - deviation of piezocrystal, measurement of the coherent length of optical source and measurement of the index of refraction of tramsparent materials. The manner of optical coherent detention and its utilization in optical communication systems is indicated. After demonstration of the principle was carried out the measuring of detection of optical signal modified by the external modulator.
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Vectoring in xDSL systems
Rada, Dominik ; Číž, Radim (referee) ; Šilhavý, Pavel (advisor)
This bachelor's thesis presents the approximation of VDSL2 and G.fast transmission systems according to pre-selected cable types. The thesis is also focused on the principle of vectoring and its use. The components of the thesis are explained by initialization process in modems with support of vectoring and approximation of Pre-Coder algorithms. A part of the thesis is a created user application in MATLAB, which displays the influence of vectoring on the transfer rates based on user input. In addition, the application captures primary and secondary line parameters, transmission characteristics, and transmitted masks.
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A Method to Supress Interferences in Wigner-Ville Distribution
Pikula, Stanislav ; Pazdera, Luboš (referee) ; Hájek, Karel (referee) ; Beneš, Petr (advisor)
The doctoral thesis focuses on signal representation in the time-frequency domain with constant resolution. In theoretical introduction the possibilities of displaying a signal in time and frequency are summarized. Attention is concentrated on comparison of short-time Fourier Transform (STFT) and Wigner-Ville Distribution (WVD). The latter achieves a significantly better resolution, especially for a linearly modulated signal. The disadvantage of WVD, which is the presence of interferences resulting from the calculation of the instantaneous autocorrelation function, is described in detail. These interferences are due to the presence of multiple components in the signal or its non-linear modulation. Subsequently, several methods are discussed, which can suppress these interferences, but at the cost of resolution loss. One of the interference suppression methods is smoothed pseudo Wigner-Ville distribution. It is further used in this thesis for the analysis of interference suppression when various filtrations in the time-frequency plane are applied. Several signals with multiple components or various non-linear modulations are used. Based on the analysis, a method using a set of variously smoothed pseudo Wigner-Ville distributions is designed to estimate the time-frequency representation with high resolution and minimal interferences. To compare the results to other methods, the quantitative metrics used in the literature are compared. To select the appropriate one a new metric is suggested. It is applicable to simulated signals and uses mean square error. Based on the comparison, the Stankovi\'{c} measure is selected as the most appropriate for comparing results. The selected metric is used to determine the appropriate minimal number of differently smoothed pseudo Wigner-Ville distributions. Using the selected metric, the proposed method is compared with other methods. These are STFT with optimized window length, S-method with optimized parameter and optimization method using radial Gaussian kernel (RGK). These methods are compared based on the set of signals previously used for interference suppression analysis. In addition, noises are added to the signals. Finally, the methods are also compared based on the real bat echo signal. In conclusion, the proposed method outperforms the compared methods in suppressing interference and resolution.
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