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Wideband transimpedance photodiode amplifier
Šťastný, Martin ; Roubal, Zdeněk (referee) ; Drexler, Petr (advisor)
This thesis deals with the design of transimpedance amplifier with high gain. There are described different principles of semiconductor sensors of optical signal. There is also a comparison of different methods of converting the photocurrent to voltage. It also discusses the design of an appropriate feedback capacitor in terms of stability in participation as a transimpedance amplifier. It examines the impact of non-zero currents flowing to the input operational amplifier circuit functionality and output offset compensation. Part of the thesis is a simulation that confirms the calculated values. The thesis also deals with the implementation of the receiver and the method of correct measurement of the cut-off frequency.
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Detection of closure of chamber doors for an electron scanning microscope
Obšitník, Michal ; Drexler, Petr (referee) ; Nešpor, Dušan (advisor)
The aim of this work is to design a suitable sensor for the detection of the chamber door position in an electron scanning microscope when the pressure in the vacuum chamber is changed and a control program is assembled to the selected sensor. The detected motion is within one millimeter. In the first part, the work is aimed at getting acquainted with the principle of functioning of the electron scanning microscope and with the basic types of sensors for position and mechanical force detection. Subsequently, the sensors are compared according to three basic categories: price, range, and resistance to external influences. Selected theory-based sensors are tested to exclude inappropriate sensors from use. After testing, the Interlink FSR-402 resistance sensor is selected. The scheme is connected to the sensor and the operation control program is created. The result of this work is a force sensing sensor, which is triggered by the pressure of chamber door on the chamber wall when creating a vacuum and a control program that controls the results measured from the sensor and adjusts them as required.
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Design and Realization of Metamaterial
Kovaľová, Soňa ; Drexler, Petr (referee) ; Nešpor, Dušan (advisor)
The thesis discusses the design of periodic resonant structures, studying of their impact to surrounding electromagnetic field and realisation of magnetoinductive lens with potential application in nuclear magnetic resonance imaging. Frequency tuning of structure by variation of different parameters is described. The finite element method in Ansys HFSS was used to analyse the properties of designed structures.
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Fast optical receiver for measurement application
Žádník, Jakub ; Steinbauer, Miloslav (referee) ; Drexler, Petr (advisor)
This bachelor's thesis analyzes the problem of a detection of analog optical signals on frequencies nearing 100 MHz. The theoretical part describes a principle of the basic photodiode types and their parameters including their equivalent circuit and parasitic characteristics. Next we discuss the ideal circuit selection and its components, especially the photodiode and operational amplifier. In the practical part we simulate the circuit in the software Tina-TI and measure chosen photodiodes. After that, real circuit boards are designed, constructed, soldered, tested and adjusted to achieve the best performance possible.
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The design Spice models OA with verification their accuracy
Kučera, Tomáš ; Drexler, Petr (referee) ; Roubal, Zdeněk (advisor)
This bachelor thesis describes the design macromodels of operational amplifiers on the 5th level. Macromodel is designed from the measured parameters of the integrated circuit and created first Boyleho model and later model of multiple pole/zero. The proposed circuits are created using the entire library program OrCAD PSpice. The created macromodel can enter certain common parameters and simulate the manufacturing tolerance and mark modeled to a limited extent, other types of OA. The measured parameters are compared with results of PSpice simulation program and verified the accuracy of the method used for the design macromodel. Models are also suitably modified to simulate the noise voltage.
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RF power meter
Hlaváč, Štěpán ; Jedlička,, Petr (referee) ; Drexler, Petr (advisor)
This master’s thesis describes various principles of measurement of electromagnetic waves in a free space and on a line. Used sensors and their real parameters are given for every method. The analysis of protections of high-frequency inputs of measuring instruments is done here and the most suitable method and protections of input for realization are chosen. The analysis of design of secondary protection of high-frequency input is done in this project. The protection of input is realized and measured. The suitable method of measurement is chosen as well as the sensor for measurement of power. The block diagram and circuit diagram of the meter of power are designed. According to designed conception the measuring instrument for measurement of power is realized and its single qualities are measured during the realization. In the final part its precision is measured and the evaluation of results is done.
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Vector phase-sensitive measurement amplifier
Rejnuš, Milan ; Vlček, Čestmír (referee) ; Drexler, Petr (advisor)
The master’s thesis describes known methods of signal measurement using principle of synchronous detection. Various methods are presented, their principles are examined and the problems when using them are analyzed. Further, procedures for reduction of adverse effects are described also. Second part of this thesis is focused on the instrument design. The instrument is intended for detection and processing of the output signals in a given optometric system. The proposed device is designed to operate on the principle of synchronous detection method using a vector signal evaluation. Advantages and disadvantages are discussed below.
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RF analog fiber optic link
Kelbler, Petr ; Jedlička, Petr (referee) ; Drexler, Petr (advisor)
This thesis analyzes the problem of design analog fiber optic link for transmission high frequency signals. Analog fiber optic link will be used in system for detection and localization a partial discharge activity MOSAD-PD-UHF, where will replace existing solution with coaxial cables, which is not appropriate for highly noise environment. MOSAD-PD-UHF system is developed in department of theoretical and experimental electrical engineering. At the first, MOSAD-PD-UHF system and individual parts of optical chain are theoretical described. In following part are compared a few commercially available analog fiber optic link and design of chosen transmit and receive module are described. . The thesis final part deals with construction of optical link and measured parameters are discussed.
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