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Radar antenna diagnostic module
Pacner, Petr ; Urbanec, Tomáš (referee) ; Kubíček, Michal (advisor)
Faults like open and short circuit in electrical wirings pose a significant threat on functionality of the whole application. This thesis describes conceptual design of a fault identification module for coaxial cables between transmitter and antenna in radar systems, and focuses on faults localization. The main goal is to select from existing a suitable method for such faults analysis and create a demonstration module serving as a basis for further development. This contains theory regarding basic classification of wiring faults and principles of frequently used detection methods including some of their prameters, advantages and disadvantages which altogether build a foundation for method selection. The chosen method is analyzed by simulations and further on laboratory equipment controlled by a set of computer applications. In the end the chosen method is implemented on a development kit, which is then used for measurements of wire sample.
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High Efficiency Microwave Power Amplifiers - Laboratory Experiment
Gajzler, Jakub ; Svačina, Jiří (referee) ; Urbanec, Tomáš (advisor)
This Diploma thesis deals with methods that increase efficiency of transistor amplifiers. In the first part of the thesis we describe theoretical background of the constructions of power amplifiers. At first we deal with the classical method that is concerned with a change of position of the static operating point. Secondly we cover the multi harmonic manipulation method (MHM). This method is concerned with a proper loading of particular harmonic components and consequential shaping of voltage runs and currents on the collector. In the second part of the work we have constructed the substitutes of particular accesses. Constructed classes are AB, F and FMHM. Basic S parameters and output signal spectrum were measured. We can see from the calculated efficiencies AB = 11%, F = 16% a Fmhm = 18%, big increase of efficiency F and FMHM only by changing output network.
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Magnetic loop antenna with electronic tuning for frequencies below 30MHz
Burda, Miroslav ; Láčík, Jaroslav (referee) ; Urbanec, Tomáš (advisor)
This project deals with electronic tuning and automated adjustment of magnetic loop antennas, working in the High Frequencys. The whole work is divided into three parts tuning, adjustment and control). The tuning part is realized by changing the capacity of the array capacitors and adjustment is done by different changes of power points. The whole system is controlled by a microprocessor ATmega16. According to utility switches the microprocessor capacity, which tunes the antenna to the required frequency, processes information about power adjustment and fine-tuning the antenna by changing the position of charging.
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FM Coincidence Detector - Laboratory Equipment
Mlčoch, Jiří ; Urbanec, Tomáš (referee) ; Baran, Ondřej (advisor)
This work is aimed at an analysis of frequency demodulation, design, simulation, and construction of a coincidence demodulator. Chapter 1 explains the basic characteristics of frequency modulated (FM) signals and provides an overview of the required signal bandwidth, the signal spectrum, and the signal-to-noise ratio after demodulation. Chapter 2 describes each type of FM demodulator separately, and it includes all significant types of demodulator for FM radio broadcast. The function of the coincidence demodulator and its characteristics are explained in detail. Chapter 3 contains a theoretical solution of the phase shift network. Calculated values of the circuit elements are verified by simulation with a view to the total harmonic distortion of the demodulator output signal. Chapter 4 describes the front-end circuit of the receiver. Here, the filter design and the mixer circuit description are provided. The final part of the thesis presents the applicable laboratory task.
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External Part of the Receiving System for UHF Satellite signals
Sýkora, Jan ; Herceg, Erik (referee) ; Urbanec, Tomáš (advisor)
This bachelor thesis deals with omnidirectional antennas in the UHF band, especially Lindenblad’s omnidirectional antenna and its nulls in the radiation pattern. The aim was to design a preamplifier, power supply circuit and bias tee with the transmission of power supply, UHF signal and reference GPS signal through single coaxial cable towards a receiver. A further requirement was to design a mechanical part of the antenna which holds it together with considering modern manufacturing processes - 3D print. The final task was the measurement of antenna’s real parameters.
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Tuner for UHF Receiver with Low Power Consuption
Kaštánek, Martin ; Vágner, Petr (referee) ; Urbanec, Tomáš (advisor)
The purpose of this work was to make a proposal for input parts of receiver for band 430 to 440 MHz. A model of chosen semiconductor triode BFP540 was created in simulation software. Possibilities how to decrease consumption of this semiconductor triode, keeping the profit, were investigated through the simulation.In compromise consumption, keeping the profit of the amplifier - an optimal operating point for this semiconductor triode UCE = 1,2 V and IC = 2 mA was found. It was tested through the testing wiring with noise microstrips conformity. Ascertained knowledge was used for construction of tuner for UHF receiver. An operating point of input amplifier of UHF receiver was owing to power supply amplifier forced for bigger effectiveness to UCE = 2,65 V and IC = 2,0 mA. Suppression of mirror frequency is provided with Helix filter of the third order, because of intermediate frequency 10,7 MHz. Mixing on intermediate frequency is made again by semiconductor triode BFP540. Selectivity of receiver is provided with intermediate frequency crystal filter 10,7 MHz with bandwidth 15 kHz. Designed input part enables reception of SSB, FM and digital types of modulation.Bandwidth intermediate frequency exit is adapted to this request To receive particular modulation , it is necessary to complete intermediate frequency signal way with appropriate intermediate frequency filter.
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Methods of testing printed circuit boards
Průša, Tomáš ; Urbanec, Tomáš (referee) ; Raida, Zbyněk (advisor)
ABSTRACT This work describes design of tester for motherboards that uses the PC's called CM-iTC and analysis of input / output pins. There are combinations of inputs / outputs for tested boards and modules focusing on possible errors and their specifications. They include proposals for solutions to detect these errors.
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