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FM Transmitter of APRS Telemetry in 144 MHz Band
Bohátka, Jan ; Šádek, Václav (referee) ; Urbanec, Tomáš (advisor)
APRS system is described are sent toin my essay, which is used for sending and receiving text messages. The text messages frequenc 144 MHz by using the modulation scheme AFSK. APRS communicate by using the protocol AX 25, which sends and receives the text messages in the area where are carried despatches and control bits as well. The whole area of high frequency part is in one integrated circuit. The control, coding and decoding of the area is the microcontroller’s job.
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FM Transmitter of APRS Telemetry in 435 MHz Band
Klíma, Martin ; Špaček, Jiří (referee) ; Urbanec, Tomáš (advisor)
FM transmitter APRS of telemetric data is device able to measure telemetric values from its ambient. It is able to send this data to user on earth by radio frequency channel. This device can create data frames, with proper formatting allowing sending data. It operates in 435 MHz band, uses FSK and AFSK modulation. This work describes basic information of used protocols, electronic connection of this transmitter and software equipment.
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Control and Diagnostic System for I2C Bus
Juhás, Miloš ; Šebesta, Jiří (referee) ; Urbanec, Tomáš (advisor)
The objective of this diploma thesis is design and realization of I2C bus analyzer. I2C bus protocol is briefly described, together with means of connecting devices to the bus. Next the basic requirements for I2C bus analyzer are defined. Then the design of hardware I2C-to-USB converter including block description is proposed. The chapter dedicated to converter firmware describes method of communication with PC, decoding of intercepted commands and principles of master, slave and passive mode of bus monitoring. The last part is focused on operation software and its structure. Described are individual interfaces, most notable classes and default plugin modules.
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RF Generator up to 4.4 GHz with ADF4350
Frydrych, Jiří ; Šádek, Václav (referee) ; Urbanec, Tomáš (advisor)
The aim of this work is design, realization, and measurement of wideband microwave generator, which is based on the ADF4350 frequency synthesizers. The generator uses the principle of mixing, for frequencies up to 2.2GHz. Higher frequencies are obtained through direct channels. The first part describes the theory of phase locked loop . The following section describes the parameters of the ADF4350 and their management. A PCB was also designed to control the generator with Atmel s AVR AT-mega32. The Generator software is written in AVR Studio in C programming language. The realized generator is housed in a stainless steel box and can be controlled using the keyboard and PC.
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FM Transmitter of APRS Telemetry in 144MHz Band
Sabol, Martin ; Špaček, Jiří (referee) ; Urbanec, Tomáš (advisor)
This work deals with analysis of protocol APRS Automatic Positioning System for telemetry. There is analyzed the structure of the most important frames and their application. It discusses the processing of GPS data and subsequent modulation of the selected frequency. This work also describes and discusses the proposed peripheral devices and the used firmware.
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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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Design Rules for Electronic Systems with ATMEL Microprocessors from the EMC Point of View
Kaštan, Jiří ; Svačina, Jiří (referee) ; Urbanec, Tomáš (advisor)
This diploma thesis is dealing with the basic knowledge of the Electromagnetic compatibility. It’s concretely target on electromagnetic interference flowing from the application of electronic gas control by Honeywell company. Author compile the power control board with including software in language C. The next alternates of power control board with the separated microprocessor were designed for the more extended source detection. On these boards there were explored shielding surface features placed directly under the microprocessor. The application reducing the interference was designed in accordance to the rules finding out during this diploma thesis writing.
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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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