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VHF SSB Receiver with Low Consumption
Matoušek, Martin ; Povalač, Aleš (referee) ; Urbanec, Tomáš (advisor)
This work is focused on proposal of SSB receiver operating at 30 MHz. The design was primarily focused on simplicity and low power consumption. This work was realized for the transmission of audio signals. SSB modulation is far more efficient in terms of the radio spectrum used. First part of this thesis describes a block diagram of a receiver. Next parts are focused on proposal of individual blocks of the receiver, especially its most important parts. Finally, the overall evaluations of the design characteristics of SSB receivers are discussed.
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Low noise 70 cm band amplifier
Klügl, Jan ; Vágner, Petr (referee) ; Urbanec, Tomáš (advisor)
This master's thesis is engage in suggestion of low noise 70 cm band amplifier with filter and diode attenuator. At first the thesis describes the basic parameters of amplifier, for example gain, noise figure and dynamic extent. Later in detail describes individual parts, which are the device consist of. At every part of system is mentioned the diagram of connection and values of components, which are ascertained from calculation, simulation and recommendation of producer. The characteristic parameters of amplifier were measured after construction.
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Computerized measurement of characteristics of analogue functional blocks
Pšeno, Daniel ; Urbanec, Tomáš (referee) ; Brančík, Lubomír (advisor)
Aims of this bachelor`s thesis were design laboratory appliance with controlled sources and programming in graphic development software VEE by Agilent. The appliance will be including all four types of controlled sources. It will be applied on place of computerized measurement system in laboratory of Analogue electronic circuits. Program will be working with all of measurement devices on work place. PC is connected to all measurement devices by GPIB bus. In the first part of this project is talked about computerized measurement system work place, graphic development software, about programming of devices and designed four programs in VEE. In the second part of this project are included simulations of all types of controlled sources in software PSpice. Optimal ratio constants are set up by the simulation output. Printed circuit board is designed in Eagle software.
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Mobile workplace for field strength measurement
Gašpierik, Andrej ; Urbanec, Tomáš (referee) ; Láčík, Jaroslav (advisor)
The aim of this work is how to construct mobile workplace for automated field strength measurement in depending on the distance from transmitter. This is a very sophisticated device. It can be used during covering buildings wi-fi or GSM. DEPARTMENT OF RADIOELECTRONICS FEKT VUT in Brno is going to use this workplace on lessons of subject Proposal antennas and radio links. This thesis summarizes the problematics of extension and measurement of electromagnetic waves, pissibilities of measuring the distance, communication between microcontroller ATmega16 and notebook via USB bus, data reading from the spectrum analyzer and the precessing of these results in the user interface. The whole device that can render how changes signal power at increasing distance from the source of the signal has been designed and tested.
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Magnetic loop antenna with electronic tuning for frequencies below 30MHz
Burda, Miroslav ; Vágner, Petr (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 autimatically fine-tuning the antenna by changing the position of charging.
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Subharmonic Mixers for Microwave Bands
Kintr, Jindřich ; Frydrych, Jiří (referee) ; Urbanec, Tomáš (advisor)
The task of this master’s thesis is design and implementation subharmonic mixer for the microwave band. Subharmonic mixer is based on the principle of antiparallel diode. In the first two parts are theoretically described mixers (subharmonic mixer) and topology suitable for implementation. Another work describes the design subharmonic mixer. The proposal is implemented in the program Ansoft designer. DPS is created in Eagle or in Ansoft Designer. The mixer is designed and implemented first on the lower frequency and consequently at higher frequencies (24,048 GHz and 47,088 GHz). Work also includes the measurement results of the mixer.
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Power amplifier for 435MHz Band with High Efficiency
Herceg, Erik ; Špaček, Jiří (referee) ; Urbanec, Tomáš (advisor)
This diploma thesis is focused on design of high frequency power amplifiers in UHF band, specifically at 435 MHz. Amplifiers are designed in different classes of operation. The thesis deals with the comparison of main parameters in each class of operation, the most important parameter is effeciency. The amplifying part is unipolar transistor which is working in Single-stage mode. The results were simulated in Advanced Design Systems Software.
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Selective Circuits - Laboratory Experiment
Košťál, Stanislav ; Vágner, Petr (referee) ; Urbanec, Tomáš (advisor)
The aim of this thesis is to describe the distribution and behavior of selective circuits and methods for their implementation. There are formulas provided for the calculation of the frequency components of selected second-order RLC filters. It further describes the choice of filter frequency components and computing relationships needed for the construction of coils. The work also includes a description and complete information needed for making measurements of the measurement of the RLC band-pass. The annex to this work includes all the materials needed for implementation of laboratory tasks designed to measure using the product.
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Magnetic Loop Antenna with Electronic Tuning for Frequencies below 30MHz
Svoboda, Luděk ; Vágner, Petr (referee) ; Urbanec, Tomáš (advisor)
The aim of this bachelor's project was realization of a tuning system with complete software and testing of the system's functionality and parameters of antenna. The system is divided into two parts, tuner and controller. The tuner implements change of circuit capacity by switching capacitor series. For switching is used transistor with small transitional capacity but small maximal collector current, too. This parameter restricts the use of system. The second part, controller, uses microcontroller AT89C2051. The microcontroller switches capacitors (and thus sets frequency) according to requests sent from PC with control software. The functionality was checked by tests with network analyzer.
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