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Programmable attenuator for laboratory measurement
Husslik, Tomáš ; Šimka, Marek (referee) ; Polák, Ladislav (advisor)
This thesis deals with the design of a programmable attenuator with digital control. The main objective of the work is to design and create an attenuator with a nominal impedance of 50 , providing adjustable attenuation in the range of 0 to 40 dB, functioning within a bandwidth of 1 to 2 500 MHz. Control of the proposed attenuator is facilitated by a microcontroller that manages the settings of an integrated circuit attenuator. Furthermore, the attenuator features a basic user interface. A PCB was designed for the attenuator and subsequently manufactured. The device was then assembled and its key parameters were measured.
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System for control of high-frequency power source with reflected power measurement
Zoufalý, Ondřej ; Drexler, Petr (referee) ; Juřík, Karel (advisor)
This thesis briefly describes the function of the selected high-frequency technology and its use. Furthermore, the thesis contains a discussion of the method of designing a system for control of high-frequency power source with reflected power measurement, after which the selection of suitable components is carried out based on pre-selected parameters. Subsequently, the method of powering and cooling the system is proposed. This is followed by the actual assembly of the system and testing of its functionality and measurement of system parameters. In the last part, selected parts of the printed circuit board of this system are described and justified.
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Antenna for mobile high power microwave generator
Kračmar, Leoš ; Láčík, Jaroslav (referee) ; Mikulášek, Tomáš (advisor)
The bachelor thesis deals with the design and practical implementation of a magnetron connected to waveguide as an excitation source for a linear slot antenna array. The goal was thorough acquaintance with the issue of partial parts of designs, verification of calculated parameters using software simulations and practical measurements on manufactured parts of the project. In the first part of the work, it theoretically deals with used components, used parameters and by software design of a magnetron to waveguide transition model with practical measurement. The second part of the work contains calculations and simulations of the design of a linear slot antenna array, which continues by series of practical measurements of antenna properties.
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RF power meter
Hlaváč, Štěpán ; Jedlička,, Petr (referee) ; Drexler, Petr (advisor)
This master’s thesis describes various principles of measurement of electromagnetic waves in a free space and on a line. Used sensors and their real parameters are given for every method. The analysis of protections of high-frequency inputs of measuring instruments is done here and the most suitable method and protections of input for realization are chosen. The analysis of design of secondary protection of high-frequency input is done in this project. The protection of input is realized and measured. The suitable method of measurement is chosen as well as the sensor for measurement of power. The block diagram and circuit diagram of the meter of power are designed. According to designed conception the measuring instrument for measurement of power is realized and its single qualities are measured during the realization. In the final part its precision is measured and the evaluation of results is done.
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Power amplifier for 2 metres radio amateur transmitter
Klapil, Filip ; Vařacha, František (referee) ; Prokeš, Aleš (advisor)
This work deal with development a solution of a power amplifier for 2 metres radio amateur transmitter with a minimum output of 1 kW. Part of the solution is to use a commercial module of power amplifier. In addition, the design of the input attenuator, the switching elements in the signal path, the output filter and the protection circuits including cooling. The bachelor thesis contains a proposal of a system solution with a discussion of required performance and legislative requirements. This is followed by a hardware section, where the work is devoted to the design of the hardware, the theoretical calculation of the components and the simulation. In 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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Audio Pre-Amplifier for Laboratory Measurements
Friml, Vilém ; Hanák, Pavel (referee) ; Kratochvíl, Tomáš (advisor)
This thesis deals with a design of audio pre-amplifier with fixed frequency filters and a choice between amplification using integrated circuits and solidstate circuit. The thesis includes a design of attenuation circuit, an amplifier with an integrated circuit, an amplifier with transistors, a RIAA filter, a speech filter, a physiological filter, a rock preset filter and a power supply circuit. The thesis describes design of the circuit board, solution of oscillations of the amplifier with transistors and a measurement of the constructed device. The aim of the thesis is the design and construction of laboratory equipment.
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Pure tone audiometry
Maršálková, Leona ; Harabiš, Vratislav (referee) ; Chmelař, Milan (advisor)
The presented master’s thesis deals with the acoustics, specifically with the selected characteristics of the sound. It focuses on the anatomy of the auditory system and its function. The work describes the testing approaches for an evaluation of the auditory organ function and introduces modern methods used for the hearing tests, especially pure tone audiometry. A part of the thesis is dedicated to a concept of an audiometer for pure tone audiometry, which is presented in a detailed block diagram along with a description of its working components. Included chapters describe the partial circuits of the audiometer supplemented by the calcuations of its individual elements. The concluding part of the thesis deals with the evaluation of the device’s functionality.
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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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System for control of high-frequency power source with reflected power measurement
Zoufalý, Ondřej ; Drexler, Petr (referee) ; Juřík, Karel (advisor)
This thesis briefly describes the function of the selected high-frequency technology and its use. Furthermore, the thesis contains a discussion of the method of designing a system for control of high-frequency power source with reflected power measurement, after which the selection of suitable components is carried out based on pre-selected parameters. Subsequently, the method of powering and cooling the system is proposed. This is followed by the actual assembly of the system and testing of its functionality and measurement of system parameters. In the last part, selected parts of the printed circuit board of this system are described and justified.
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Antenna for mobile high power microwave generator
Kračmar, Leoš ; Láčík, Jaroslav (referee) ; Mikulášek, Tomáš (advisor)
The bachelor thesis deals with the design and practical implementation of a magnetron connected to waveguide as an excitation source for a linear slot antenna array. The goal was thorough acquaintance with the issue of partial parts of designs, verification of calculated parameters using software simulations and practical measurements on manufactured parts of the project. In the first part of the work, it theoretically deals with used components, used parameters and by software design of a magnetron to waveguide transition model with practical measurement. The second part of the work contains calculations and simulations of the design of a linear slot antenna array, which continues by series of practical measurements of antenna properties.
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