National Repository of Grey Literature 12 records found  1 - 10next  jump to record: Search took 0.00 seconds. 
Influence of the antenna instalation method on the roof of the railway vehicle on achieved antenna parametres and radiation pattern
Drtina, Vojtěch ; Richterová,, Marie (referee) ; Theumer, Radek (advisor)
This thesis investigates the optimal placement of antennas for the system ETCS (European Train Control System) on railway vehicle and analyzes the impact of surrounding structures on the radiation characteristics of these antennas. The goal is to analyze and propose antenna placement to achieve maximum reliability in communication between vehicular antennas and the ETCS infrastructure. The thesis presents simulations of various antenna placements on 18Ev and 15Ev units as well as the methodology for real measurement of these vehicles. The thesis addresses the measurement and simulation of antenna radiation on large objects that cannot be placed in an anechoic chamber.
Class AB audio power amplifier for home use
Vaško, Dominik ; Theumer, Radek (referee) ; Brančík, Lubomír (advisor)
This bachelor's thesis deals with the design of a classic class AB audio power amplifier with a minimum power of 2x25W intended for home use and the design of a suitable power supply unit. The final stage of the amplifier is realized by an integrated circuit LM3886, which is supplemented by the design of a correction preamplifier and an excitation indicator. The correction preamplifier is implemented using the LM1036 integrated circuit, the excitation indicator, in turn, by the LM3915 integrated circuit. The results of the work are designs for the schematic connections of the final stage, correction preamplifier and excitation indicator, as well as designs and implemented printed circuit boards and the resulting device with measured characteristics.
ZVS/ZCS converter for induction heating
Gadas, Jan ; Šotner, Roman (referee) ; Theumer, Radek (advisor)
The bachelor thesis deals with the design of high-frequency inverters with low-loss switching applied as an induction heater. Four known inverter topologies are presented in the thesis. The aim of the thesis is to select a suitable topology on which the induction heating will be implemented according to the theoretical knowledge found and subsequent simulations. The result of the semester thesis is a functional low-power model of an induction heater implemented on a PCB. The result of the bachelor thesis is high-power model of an induction heater for industrial use. Functionality tests and comparison of measured data with simulations are performed for both. For industrial induction heater, a melting test was performed with analysis of element content on spectrum analyzers to demonstrate use.
Low-frequency electronically adjustable active load
Vaněk, Petr ; Theumer, Radek (referee) ; Šotner, Roman (advisor)
SBachelor thesis deals with the design of an active electronic load for DC and AC input signals. The PSpice simulations are used for verification of mentioned modes of the electronic load operation and the principles of their functions. The main content of this work is the design of low frequency active electronic load, design of control performance and verification by it‘s simulation, preparation of production documents, completion of prototype and experimental verification.
Low-frequency active threshold-less voltage detectors
Litovska, Anna ; Theumer, Radek (referee) ; Šotner, Roman (advisor)
This bachelor thesis deals with various solutions of the active topology of voltage detectors and rectifiers that do not use diodes. Specifically, it focuses on discrete detectors with multipliers and voltage-to-current converters, a discrete peak detector with transconductors, and an integrated RMS detector with an AD734 multiplier. This thesis includes theoretical design of parameters of circuits for required features as well as verification by computer analysis (PSpice) and experimental measurement. This work includes documentation for construction of the product, including the block arrangement and the design of the printed circuit board.
Synthesis of frequency filters with ability of the electronic reconfiguration
Theumer, Radek ; Šotner, Roman (referee) ; Langhammer, Lukáš (advisor)
This bachelor thesis deals with proposal of frequency filters providing electronic controllability of its transfer function. The main aim was to propose new filtering structures working in voltage and current mode based on suitable proposal methods. Active elements are implemented by available operational transconductance amplifiers, current amplifiers and conveyors, eventually voltage amplifiers. Four different active controllable filters are presented. Their function is simulated in software PSpice with help of models at transistor level in comparison with ideal behavior (idealized models). Two designed filtering structures were chosen and complemented on parasitic, sensitivity, stability, temperature analysis and Monte Carlo analysis. These circuits were realized on PCB. Measurement results are presented at the end of thesis, including comparison with simulations.
Design of basic analogue building blocks with fractional-order transfer
Theumer, Radek ; Staněk, Miroslav (referee) ; Langhammer, Lukáš (advisor)
This diploma thesis is focused on design of the analogue circuit structures with integer-order and fractional-order transfer. The ways in which fractional-order transfer functions can be achieved are mentioned in the introduction. Two basic building blocks with the ability to control its transfer function order and frequency, such as integrator and differentiator respectively, were designed. A non-traditional active element was used in proposed analogue building blocks. In addition, the inner structure of this active element has been improved to provide the ability to control another suitable parameters. Aplication of the proposed fractional-order integrators is presented by employing into the frequency filter. Simulations are performed with help of transistor-level models of two different technologies: CMOS TSMC 0,18 um in the OrCAD Pspice software and I3T25 in the CADENCE Virtuoso software too. All proposed circuit structures are realized on the printed circuit board (PCB) and then measured experimentally. The last part is focused on comparative measurements of the filters with fractional-order integrator proposed by another author.
Low-frequency active threshold-less voltage detectors
Litovska, Anna ; Theumer, Radek (referee) ; Šotner, Roman (advisor)
This bachelor thesis deals with various solutions of the active topology of voltage detectors and rectifiers that do not use diodes. Specifically, it focuses on discrete detectors with multipliers and voltage-to-current converters, a discrete peak detector with transconductors, and an integrated RMS detector with an AD734 multiplier. This thesis includes theoretical design of parameters of circuits for required features as well as verification by computer analysis (PSpice) and experimental measurement. This work includes documentation for construction of the product, including the block arrangement and the design of the printed circuit board.
Fractional-order integrator and its application in FLF fractional-order frequency filter
Theumer, Radek ; Langhammer, Lukáš
The main aim of this paper is to introduce the proposal of fractional integrator by approximation of the integer-order follow-the-leader-feedback topology (FLF). Current differencing transconductance amplifier (CDTA) is used in the integrator due to the higher versatility of this building block. The proposed integrator is also implemented to the frequency filter, creating a fractional-order frequency filter in FLF topology. The main advantage of this circuit is its electronic controllability. The resulting circuits (integrator and filter) are simulated in OrCAD using a transistor models in TSMC 0.18 um technology.
Design of basic analogue building blocks with fractional-order transfer
Theumer, Radek ; Staněk, Miroslav (referee) ; Langhammer, Lukáš (advisor)
This diploma thesis is focused on design of the analogue circuit structures with integer-order and fractional-order transfer. The ways in which fractional-order transfer functions can be achieved are mentioned in the introduction. Two basic building blocks with the ability to control its transfer function order and frequency, such as integrator and differentiator respectively, were designed. A non-traditional active element was used in proposed analogue building blocks. In addition, the inner structure of this active element has been improved to provide the ability to control another suitable parameters. Aplication of the proposed fractional-order integrators is presented by employing into the frequency filter. Simulations are performed with help of transistor-level models of two different technologies: CMOS TSMC 0,18 um in the OrCAD Pspice software and I3T25 in the CADENCE Virtuoso software too. All proposed circuit structures are realized on the printed circuit board (PCB) and then measured experimentally. The last part is focused on comparative measurements of the filters with fractional-order integrator proposed by another author.

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