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Frequency synthesizer for microwave communication systems
Klapil, Filip ; Vondra, Vlastimil (referee) ; Kasal, Miroslav (advisor)
The main aim of the thesis is to develop a solution of a frequency synthesizer for a microwave communication systems. Specifically, it suggests a design for frequency synthesizer with phase-locked loop. At beginning of the thesis the principle and basic properties of this method of signal generation are explained. Then it is followed by a brief discussion of the parameters of synthesizers and their influence on design. Another part of the work is the analysis of circuit the frequency synthesizer with the phase-locked loop MAX2871, which is followed by a proposal for the design of the frequency synthesizer module hardware. The last part of the work deals with practical implementation, verification of function and measurement of achieved parameters and their evaluation.
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Design and Simulation of Single Phase Active Rectifier
Bareš, Jiří ; Huták, Petr (referee) ; Klíma, Bohumil (advisor)
This thesis deals with single-phase active rectifier, strategy of control and simulation of its model. In the beginning of this work a principle of rectifier is described along with transistor switching system, which has impact on shape of input current. Dimensioning of rectifier for assembling model and designing of control, including phase-locked loop and regulators follows. In the end assembled model and its simulation is described.
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Design of magnetic bar-code read head
Kadlčík, Libor ; Drexler, Petr (referee) ; Mikulka, Jan (advisor)
Magnetic bar-code is composed from ferromagnetic bars printed on a substrate. The amount of ferromagnetic material is low, therefore reading magnetic barcode requires sensitive methods. Principle of methods of sensing both low-intensity magnetic field (fluxgates) and detecting low concentration of ferromagnetic material (resonant circuit, differential sensor) will be described. There are sensors producing frequency-modulated signal, therefore we focus on frequency demodulators as well. Signal acquired by sensor suffers from convolution distortion, reconstruction methods will be introduced. The assembled device consists of sensing oscillator, frequency demodulator, amplifier and reconstructing circuit. Frequency demodulation is done by phase-locked loop or differential demodulator. Reconstruction is based on detection of inflection points, producing square signal (representing bars of barcode). Design of these blocks is described. The device is able to read magnetic barcodes and reconstruct convolutionary distorted acquired signal. The differential demodulator exhibits low noise and low temperature drift (contrary to phase-locked loop). Signal produced by reading 2 mm wide bars is reconstructed without any problems, bars of width less than 1 mm cause troubles in certain cases (due to high degree of convolution distortion).
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Control Unit for VHF Radio Receiver with Frequency Synthesizer
Sobotka, Martin ; Šebesta, Jiří (referee) ; Vyskočil, Pavel (advisor)
The aim of this work is to propose the involvement of the control unit for receiving VHF radio and its practical implementation. Adding a panel on the appropriate tuner unit leads to a complete receiver to receive radio broadcasts. My work is to focus on two frequency bands: VHF band for broadcasting and VHF band for air radio communication. This paper describes a process of selection of component, their description and integration into a complete circuit, a description of the control program for the microcontroller and a description of control device. Scheme and the draft for the manufacture of printed circuit board is attached.
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Transmitter for Professional Microphone
Árva, G.
This project deals with the design of a transmitter in a wireless microphone system, which connects to microphone through the XLR connector. The paper contains description of individual blocks which are necessary for processing and transmitting the signal generated by the microphone, describes methods of frequency modulation using a phase locked loop and compares their advantages and disadvantages. As the last, it deals with the choosing of an antenna and its adjustment to appropriate dimensions.
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