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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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RF Unit for Portable Monitoring Station
Rokos, Lukáš ; Urbanec, Tomáš (referee) ; Záplata, Filip (advisor)
The thesis describes methods for spectrum monitoring, which are used by the Czech telecommunication office. The thesis describes a design of an RF unit for a portable monitoring station and its potential use. The RF unit consists of several devices, which are connected. Devices like an antenna, a rotator, a rotator control unit, coaxial switches, an amplifier and attenuator were chosen as commercially available devices. It is also described, why were these devices chosen. Other devices such as filters, a control unit for the RF unit and a power supply were designed. The RF unit is controlled by a computer. A software for spectrum monitoring contains a graphical user interface for the RF unit control.
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Microwave circuits based on substrate integrated coaxial lines
Vídenský, Vojtěch ; Urbanec, Tomáš (referee) ; Mikulášek, Tomáš (advisor)
This bachelors thesis focuses on the problem of microwave circuits based on coaxial lines integrated into a substrate. It then takes a closer look at the parameters required for the design and modelling of power dividers. In particular, the Wilkinson 3dB divider and the 3dB square hybrid component. The operating frequency of these two dividers is designed to be 1.5 GHz. A notable section is also devoted to the design and simulation of simplified T-cell circuits.
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Satellite Position Measurement in UHF Band
Rohaľ, Pavol ; Povalač, Aleš (referee) ; Urbanec, Tomáš (advisor)
The semestral thesis deals with the problem of synchronization of software-defined radios over long distances. The goal was to design and implement synchronization with a high enough accuracy for multilateration purposes. Several basic types of software radios, methods and synchronization options are presented at the beginning. The synchronization circuit itself as well as its components were designed and built. The conclusion of the work is a detailed analysis of the chosen synchronization method and the results of the final circuit measurements.
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Antenna Mesurement System for Small Satellites
Dovičák, Ivo ; Pospíšil, Martin (referee) ; Urbanec, Tomáš (advisor)
Goal of this thesis was design and realization of a measurement system for measurement of reflection coefficient magnitude for connected antennas in 27-2500 MHz range. Measurement using resistive bridge is chosen as a suitable measurement method. System consists of electronic device controlled by STM32WB microcontroller unit and software for controller PC written in Python programming language using PyQt library. Communication between the device and controller PC is realized using Bluetooth interface. Circuitry for signal generation is based on Phase Locked Loop MAX2870. Device is powered from standard 18650 battery. Dimensions of the designed printed circuit board are suitable for use in CubeSat satellites. System can be used as a frequency synthesizer as well.
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Power Amplifier for L Band
Eliáš, Martin ; Pešek, Kamil (referee) ; Urbanec, Tomáš (advisor)
The aim of this thesis is to design a power amplifier in L-band. This thesis describes the high frequency transistor technologies. Furthermore, the communication standard of the amplified signal is described along with the output signal requirements. The design of the amplifier includes modelling of the individual amplifier stages using nonlinear models in the AWR program. The design of the stabilization and matching circuits is included, along with a circuit to guarantee the correct turn-on and turn-off sequence. The designs are converted to printed circuit board and fabricated. For the 2nd and 3rd amplifier stages, engineering drawings of the heat sinks are drawn and used to fabricate them. After implementation, the designs are measured and the measured parameters evaluated.
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S Band Antennas for Cubesat Satellites
Bekeč, Alexander ; Cupal, Miroslav (referee) ; Urbanec, Tomáš (advisor)
This bachelor’s thesis is dedicated to antennas designed for use onboard miniaturized satellites CubeSat. The main goal of the thesis was to examine suitable antennas working in the S-band for use onboard this type of satellites, create their models and simulate them in the software ANSYS HFSS together with the CubeSat frame to find out its impact on the characteristics of antennas. One of these antennas was constructed together with CubeSat frame and measured in the RF anechoic chamber. Besides these, different types of satellite attitude stabilisation were examined, along with their influence on communication with ground station. Minimal half power beamwidths of antennas were analysed for both studied types of single axis stabilisation with consideration of communication with ground station located in the city of Brno.
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BPSK transmitter for 435 MHz
Hocz, Jan ; Šebesta, Jiří (referee) ; Urbanec, Tomáš (advisor)
This thesis deals with basics of BPSK modulation. Another part compares different integrated circuits of transmitters able to use BPSK modulation on a given frequency, the choice of suitable microprocessor and transistor. Another part describes the connection of individual integrated circuits on printed circuit board and their realization. In the following section, the software and individual commands for transmitter control are described. In the final section is the functionality checked and the basic parameters reached are presented.
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Wideband 6GHz RF Signal Generator
Mička, Josef ; Kubíček, Michal (referee) ; Urbanec, Tomáš (advisor)
The goal of this thesis is a design of a wideband high frequency generator with an adjustable output amplitude. The generator is based on a frequency synthesizer ADF4355. The power level of an output signal is adjustable by an attenuator HMC1119. The created generator is accesisible trough an user-friendly control panel or by SCPI commands. Frequency synthesis can run in an integer mode or a fractional mode. The output signal has a very low phase noise when it is running in the integer mode.
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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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