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A device for demonstrating the function of oscillators with fractional-order elements
Walach, Vít ; Šotner, Roman (referee) ; Brančík, Lubomír (advisor)
This bacherol thesis deals with fractional-order elements and it’s application for RC oscillators. The aim is to carry out simulations of two different oscillators using fractional-order capacitors and then design and manufacture a device demonstrating the function of the selected oscillator. Several methods of approximation of constant phase elements are described in this work, including their circuit realization for Foster and Cauer structures. The selected RC oscillators are modeled numerically in Matlab, as well as simulated in Pspice, so that the results of both simulations can be compared. The presented oscillator with two constant phase elements is implemented on a printed circuit board. At the end of the work, the results of experimental measurements are presented in comparison with simulations.
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Frequency filters with fractal two-terminal elements
Egorov, Gleb ; Brančík, Lubomír (referee) ; Petržela, Jiří (advisor)
This thesis focuses on the use of fractal components in the design of frequency filters and phase shifters. The primary task was to calculate the characteristics of fractal capacitors with mathematical series of 0.75, 0.5, and 0.25. Subsequently, their functionality was verified using the Orcad Spice circuit simulator and in practical applications. During the work, fractal components were not only theoretically modeled but were also implemented and tested in various configurations of electronic circuits, allowing for a thorough examination of their properties and effectiveness.
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Laboratory task dedicated to filters with switched capacitors
Čipl, Jan ; Šotner, Roman (referee) ; Petržela, Jiří (advisor)
This semestral thesis deals with the issue of analog frequency filters, their division and voltage transmission characteristics of filters. Furthermore, this work is focused on the description of filters operating on the basis of switched capacitances. This work also includes simulations, which are the first draft of a laboratory preparation for teaching. The simulations were performed in the Orcad Pspice program
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The Effect of Phase Change of Water in the Green Roof Composition on the Heat Transfer Coefficient
Galata, Jindřich ; Vystrčil, Jan
The water saturated substrate layer has a significant impact on the basic requirements of buildings in the green roof composition. Apart from the impact on stability, fire safety, noise protection, etc., this research is mainly concerned with the impact on energy saving and thermal technical parameters of these structures. A current problem is that the substrate layer is neglected in the assessment of green roofs in terms of heat transfer, while the ice crystals in the substrate are beneficial as an insulating layer in winter. Therefore, the effort is to prove that in the winter months it is possible to consider a significantly higher temperature under the substrate layer than is considered in traditional calculations where the substrate is neglected.
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Interferometric measurement of phase changes of optical beam in turbulence
Děcká, Klára ; Křivák,, Petr (referee) ; Hudcová, Lucie (advisor)
This master’s thesis deals with the impact of atmospheric turbulence on phase changes of a free space optical signal. This problematic is investigated by the interferometric method. A part of the thesis is focused on the phenomenon of atmospheric turbulence. Then the physical effect of interference is discussed and optical interferometers are described. The experimental part of the thesis is focused on measurement of phase shift of optical signal by interferometric method. The result of the thesis is to determine how phase shift of an optical beam depends on the strength of turbulence.
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Ultrasonic anemometer
Hůlka, Jakub ; Mágr, Zdeněk (referee) ; Havlíková, Marie (advisor)
This master’s thesis deals with the construction and realization of an ultrasound anemo- meter. Individual types of anemometers are compared in this thesis, including mechanical, thermo anemometer and ultrasound anemometer. Different construction renderings and measurement principles of ultrasonic anemometers are analyzed. In addition, an experi- mental method of measuring the speed of sound by phase shift between two transmitting frequency is described in the document. This thesis includes the design of an control unit and the realization of a simple prototype of an ultrasonic anemometer. Experimental confirmation of the characteristics of the ultrasound anemometer is the last part of the document.
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The framework for application of phase allocation of consumers
Franěk, Vít ; Koudelka, Jan (referee) ; Vyčítal, Václav (advisor)
The aim of this work is to introduce the issue of the smart grids concept, as well as the issue of phase identification sorting from implementation smart grids. The issue of phase identification sorting is described by several possible methods. The work continues by calculating the theoretical network and processing the values measured from the low voltage network and applying the phase identification method based on voltage events. Based on the results, a laboratory task proposal is prepared.
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Methods of Accurate Measurement of Low Impedances
Mašláň, Stanislav ; Sedláček,, Radek (referee) ; Bilík, Petr (referee) ; Beneš, Petr (advisor)
Overall topic of presented thesis is development of methods of measurement of low impedances below 10 Ohm in a frequency range up to 1 MHz. The thesis comprises of three main parts. First part of thesis describes design of unique and simple calculable standards of resistance that are used for calibration of the bridge and as the reference standards for the calibrations. Next part of theses is focused on design of digital sampling bridge in various topologies suitable for measurement of various types of impedance standards up to frequency of 1 MHz. The thesis describes the HW components, data processing and corrections scheme allowing the designed bridge to reach expanded uncertainties (k=2) below 0.005% and 250 µrad at 1 MHz. One of the key points of the proposed corrections scheme is unique automatic linearity calibration method requiring minimal operator's effort. The theses also describes integration of Spice model of the bridge the bridge SW that allowed validation of functionality of the bridge and also analysis of uncertainty contributions related to interferences between the bridge components. The last part of the thesis shows selection of measurements of known impedances and international comparisons that proofs performance of the bridge.
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