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PC Controlled PLL Synthesizer
Málek, Miroslav ; Šrámek, Petr (referee) ; Vágner, Petr (advisor)
The aim of this bachelor´s thesis is a practical realization of computer controlled PLL synthesizer using USB serial port. FT232RL was used as an interface between the PLL synthesizer ADF4110 and PC. A software with graphical user interface was also developed in order to control registers of the syntesizer.
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Controll Module for Circuits with ADF4360 and Selected DDS
Lambor, Jiří ; Vágner, Petr (referee) ; Urbanec, Tomáš (advisor)
This bachelor’s thesis is focused on issues of communication between microprocessor unit and frequency synthesizer circuits - direct digital synthesis circuit (DDS), voltage control oscillator with phase lock loop (ADF). The basic theoretical function of DDS, ADF and SPI interface is described in the introduction. The solution and drafts of modules hardware are shown in next chapter. Last chapter describes programming of DDS and ADF circuits with examples of this code in C language. Schemes and board layouts of modules are attached in appendix.
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VHF/UHF Front-End for Software Receiver
Losenický, Roman ; Vágner, Petr (referee) ; Šebesta, Jiří (advisor)
The first part of this work contains the detailed analysis of the basic VHF and UHF receiver characteristics. The most important parameters, like Noise figure, selection or gain, are qualified shortly. The following chapter analyzes above-mentioned parameters and shows some calculations and analysis to design a receiver. In the third part the receiver design is proceed. It specifies a basic block diagram. The base of design is formed by a mixer SRA-1+, which choice is not part of this project. Design of preselectors is the main goal of the project. They use BF998 FET transistors and band pass filters determining three frequency bands: 140-145 MHz, 220-230 MHz and 420-430 MHz. Filtered signals go on into the channel selector afterwards. The user can determine , which one of the three input signals will be routed to the mixer, using a switching diode HSMP3823. Each part, including preselector amplifier and filters, is placed into the separated tinned boxes. These boxes are linked with the switching circuit by the coaxial line.
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LCD Matrix Display Driver
Satora, Ondřej ; Šebesta, Jiří (referee) ; Vágner, Petr (advisor)
The aim of my semestral project is a realisation of a driver matrix LCD from older NOKIA mobile phones with the PCD8544 chip. This driver is situated between an LCD and a device using it. The proposed driver should cover rendering graphical elements for the main application, thus making work with the LCD easier. This saves memory needed for using the LCD as well as computing time.
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Miniaturized Measurement System for Wind Speed Estimation.
Štěpánek, Michal ; Vágner, Petr (referee) ; Urbanec, Tomáš (advisor)
This thesis is analysis of thermal anemometer, which contains design and realization. For measuring wind speed there are not used any mechanical moving parts in this way. This measuring uses two thermistors. One of these measures temperature of air, which is very important for compensation of whole system. Temperature of second thermistor is kept on constant value. This value is higher than surrounding air temperature about constant difference. Fluctuant air cools this sensor and because of that systém must supply more of heat. By analysis of value of supplied heat, we can calculate the wind speed value.
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Precise Frequency Generator - DDS
Kratochvíl, Petr ; Vágner, Petr (referee) ; Baran, Ondřej (advisor)
This work deals with frequency generators based on the direct digital synthesis method DDS. Basic principles and attributes of the frequency generator DDS are explained. The text describes parameters influencing and defining a quality of the generated signal. The list of available integrated circuits realizing the direct digital synthesis is mentioned. A construction of the DDS generator with a device AD9954 and the generator control are described. At the end of the work, the function and parameters of the designed generator are verified.
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Microstrip lowpass filter
Kubín, Petr ; Pítra, Kamil (referee) ; Vágner, Petr (advisor)
This thesis is focused on the design of an elliptic microstrip low pass filter. In the introduction, there is discussed theory of the filter design with discrete components. Then, the following part describes the design of the microstrip filter with distributed parameters. To simulate the characteristics of the designed filter structure, the simulator Ansoft Designer V2 was used. This software was also used for final optimization of the microstrip filter.
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Low-noise S-band amplifier
Potěšil, Dušan ; Vágner, Petr (referee) ; Kasal, Miroslav (advisor)
This work deals with design, simulation and realisation of a receiving systém of an S-band front end for satellite communication. The first part of the project is designed the low noise amplifier (LNA) with high associated gain. The basic point of the design is choice of the active device. In the present time are available the ultra low noise transistors based on the GaAs with high mobility electron. The two-stage LNA has been designed with Agilent ATF-55143. It is pseudomorphic HEMTs ,which work in an enhancement mode.These transistor do not require a negative bias voltage and have extremely good typical noise figure. The design includes an interdigital tuned band pass filter between stages. The second part of the project is search another way design circuit. There are designed two LNA with paralel coupled line filter. The first has been applied on a PTFE substrate Duroid 5880 with relative permitivity 2,2 and tg d = 0,009. The substrate FR-4 (r = 4.34) with the thickness 0.06” was used for the realization.
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Computer modeling of communication systems
Polášek, Jiří ; Vágner, Petr (referee) ; Raida, Zbyněk (advisor)
The thesis will focus on using the program Ansoft Designer, more precisely, its module System Design, during simulation involving communication systems. A few examples show the work with the program on simulating the communication system without coding, and then with coding according to the standard 802.11 (Wi-Fi). The thesis also deals with creating custom blocks communication schemes. Described the creation of blocks and then their test.
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Low Noise amplifier for 8,4 GHz
Svoboda, Libor ; Vágner, Petr (referee) ; Kasal, Miroslav (advisor)
This project deals with methods of design and realization of low noise microwave amplifier for X-band. The first part describes this issue at a theoretical level. Thus it contains a detailed analysis of microstrip line and its circuit components. It is followed by some specifics of microstrip filters and with mention of microwave heterojunction transistors. The last chapter of the theoretical part describes design of small-signal amplifier with focus on low noise figure. The second part, practical, shows a concrete procedure of two-stage LNA design with HEMTs, using CAD tool Ansoft Designer. This section, as well as the bachelor’s thesis, is finished with realization of amplifier and analysis of its properties.
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