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Models of EMC filters
Kejík, Zdeněk ; Šebesta, Jiří (referee) ; Dřínovský, Jiří (advisor)
Basic problems of the EMI mains filter is explained in the introduction of this thesis. These problems appear during the measurement of insertion loss of filters and by design of EMI mains filter. The important problem is uncertainly of the terminating impedances. Eventualities measurement insertion loss of EMI mains filter and motivation of creation filter models are shown. The following part of this project shows the electronic components, from which are realized the EMI mains filter. Parasitic properties of these real devices are also discussed. The circuitry of EMI mains filter is described by the Modified Nodal Voltage Method. The optimization method called Participle Swarm Optimization is introduced, too. Basic principle and terminology are mentioned. The third part of this project is focused on the own filter and spurious components. Influence of own filter and spurious filters components on insertion loss curve are showed. Magnetic factor coefficient k is searched by the optimization method PSO. The last part of this thesis deals with creation of the alternative circuits with spurious filters components. The performances of the alternative circuits were compared with the measured data for symmetrical and asymmetrical measurement setup. The breakages in the insertion loss curve were used for determining the spurious components.
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Measurement of three-phase EMC filters
Tomašák, Lukáš ; Soldán, Josef (referee) ; Dřínovský, Jiří (advisor)
The aim of this semestral project was to propose the measuring system for measuring three-phase EMI filters in symmetrical, asymmetrical and non-symmetrical mode according to information from supplier of the filters. The major part of this project was focused on measuring the frequency dependence of the insertion loss of three-phase EMI filters in impedance systems 50?/50?, 0,1?/100 ? and 100?/0,1?. It was determined that results approximately agree with specifications in datasheets.
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Model of the metropolitan optical network
Prudík, Jiří ; Hudcová, Lucie (referee) ; Křivák, Petr (advisor)
The purpose of this master’s thesis is foremost to provide a simple guide how to build elements of optical metropolitan area network. The basic model consists to sequence of construction, network topology, passive and active parts. The collection contains examples of alternative technology such as Wireless LAN with different frequency. The optical network construction based on optical cable, fibres, splices, trays, adapters, connectors and active parts for example a lot of media convertor models. After that there are demonstrating type of wavelength division multiplexer used in metropolitan area network – passive planar PCL splitter. One of the passive planar splitter are used to increase optical fibre channel. At the end of the collection a simplified examples of used measurements – optical time domain reflectometry and optical fibre transmission. Contains standard protocols or reflectogram. The conclusion of this thesis summarizes costs of FTTb (Fibre To The Building) model of optical metropolitan area network in Czech republic and future contribution for society.
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Impedance Transformers with Impedance Ratio 1/50 Ohms for Wide Frequency Range
Zachar, Jiří ; Šebesta, Jiří (referee) ; Dřínovský, Jiří (advisor)
One of the aims of this bachelor’s project was to explore possibilities of the design of impedance transformers for a very wide frequency bandwidth (10 Hz – 100 MHz) with the impedance ratio 1/50 . It is not possible to cover this wide frequency band by one transformer, so the design was split into the design of two impedance transformers. The first transformer was realized on the ferrite coil RIK20. The second transformer was realized by with the components T16-1 and TT25-1-kk+ produced by Mini-CircuitsŽ company, and transform impedance directly in a high frequency range. The performance of realized transformers was approved by measuring transformed impedance on their outputs. The frequency band of transformers was determined from these data. Their insertion loss was also measured. The last part of this work was focused on measuring the insertion loss of EMI filters. The main task was to compare the impedance systems 1 /100 and 0,1 /100 and vice versa. The insertion loss was measured for several chosen EMI filters. The insertion loss of all filters reached approximately the same values for both impedance systems.
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