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Methods for quadrature modulator imbalance compensation
Povalač, Karel ; Valenta, Václav (referee) ; Maršálek, Roman (advisor)
Quadrature modulator (demodulator) is used in transmitting (receiving) part of many devices. Unwanted imbalance can influence amplitude, phase or DC offset of modulator (demodulator). Correction of imbalance was a main subject of thesis. Simulations of these methods were created in MATLAB and results were compared. Basics of methods were implement on programmable logic field by program Xilinx ISE. Development kit V2MB1000 with analogue board Memec P160 was chosen for this purpose. In the last part were compare simulation results with practical measurement.
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Experimental Hardware Musical Instrument
Chaňo, Petr ; Vrba, Kamil (referee) ; Dlouhý, Dan (advisor)
The main aim of the bachelor thesis was to design and build a musical instrument that will have a signs of the experimentalism consist of combination synthesizer and sequencer, tuning, unusual kind of controls and its look. At the top of this work is the theoretical introduction to the musical instruments and to the process of generating and modulating sound. There is also written information about parts that the instrument consists of (microcontroller, D/A converter), principles that leads to being able to create this instrument (operational amplifiers, frequency filters, DDS) in the theoretical part. The description of the components is in the practical part followed by the information about the circuits at this instrument and about software solution as well.
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Precise function generator
Snopek, Petr ; Horský, Pavel (referee) ; Kolka, Zdeněk (advisor)
The aim of the project is to design a concept of function generator with digital synthesis. The device will be controlled using microprocessor which allows synthesizing basic functions (sin, square, raw) as well as arbitrary functions stored in memory. User friendly graphical interface will be controlled by keyboard and rotary switch (IRC). The work emphasizes correct selection of DDS clock source, circuit elements and proper application of signal filtration method with attention to low distortion and low output phase noise.
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Direct digital synthesizerfor microwave application
Dluhý, Vojtěch ; Vondra, Vlastimil (referee) ; Kasal, Miroslav (advisor)
The aim of this thesis is introduce readers to the basics of digital frequency synthesis and design of direct digital synthesizer with circuit AD9951 by Analog Devices. The device will be controlled from a PC via USB. The device works with internal oscillator, with the ability to connect an external frequency standard of 10 MHz. On input is frequency doubler with transistor. Outpu signal is filtered by low-pass filter and amplified by monolitic amplifier ERA-3+.
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Function generator with direct digital synthesis
Gál, Radek ; Prokopec, Jan (referee) ; Frýza, Tomáš (advisor)
This bachelor’s thesis describes the design and construction of function generator, which is based on an integrated circuit of a direct digital synthesis. The device has two outputs; first generates harmonic or triangular wave and second generates square wave. Adjustment of output signal is enable with using the buttons, the incremental rotation sensor and potentiometer and displaying by using the LCD display. Generator allows adjust output frequency in range from 1 Hz up to 10 MHz with 1 Hz step size, output voltage smoothly 0 – 10 V peak-peak or using -20 dB attenuator and dc-offset in range from -5 V to +5 V. Device has RS232 interface for connect with the PC.
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DDS Based High-frequency circuit analyzer
Priškin, Jiří ; Brno), Tomáš Mádr (DCOM (referee) ; Šebesta, Jiří (advisor)
At first this thesis is dealing with the basic principles of network analyzers and afterwards goes to propose conception of a polyscope, as a special type of the scalar network analyzer, designed for magnitude frequency response measurement of two-port devices. As a result of this part of the thesis is the polyscope's block circuit diagram and also selection of key integrated circuits for sweep generator, logarithmic detector and control circuits. As the following part of the thesis is a design of the all basic analyzer's circuits resulting in their schematics diagrams and printed circuit boards, do assembly of all modules and mechanical construction of the instrument and look of the front panel. Some of the tasks is implementation of the firmware and personal computer application able to download measured data from the circuit analyzer via USB and generate chart in Microsoft Office Excel book.
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Direct digital frequency synthesizer with external synchronizing
Buš, Ondřej ; Viščor, Ivo (referee) ; Kasal, Miroslav (advisor)
This thesis deals with problematics of direct frequency digital synthesis. Principle and basic characteristics of this method of signal generating are explained in the introduction. It considers impact on purity of spectrum of output signal. Next chapter considers conception of the generator, namely choice of DDFS circuit and other basic blocks. Design of frequency multiplier, reconstruction filter and power amplifier are included. It also deals with choice of control circuit. The device is controlled by computer through USB. There was created user programme for this purpose. Measured characteristics are stated at the end of the work. This work includes schemes of connetions of designed parts including simulations and measured parameters.
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Microprocessor control unit with frequency synthesizer for SW radiostation
Povalač, Aleš ; Fuchs, Michal (referee) ; Šebesta, Jiří (advisor)
The thesis is focused on the development of a radioamateur short-wave transceiver. The basic functions, features and parameters are described in the introduction. The bandplan and appropriate types of emission are also included in the introductory part. The frequency synthesis module is discussed in the second part of the document. Emphasis is placed on the direct digital synthesis method (DDS) using modern Analog Devices circuits. The proposed DDS module includes a high-speed clock source. The description of an intermediate frequency module with a demodulator is also placed there. The final part in devoted to the design of a transceiver control panel with a graphical display, a keyboard and a rotary encoder. The firmware for an ATmega128 microcontroller is described in detail at the end of the thesis.
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Communication model using Data distribution service and communication security assessment
Frollo, Martin ; Fujdiak, Radek (referee) ; Pokorný, Jiří (advisor)
The diploma thesis is focusing on middleware layer in distributed systems. It introduces typically used communication protocols and standards operating on this layer. In theoretical part it brings closer look at OMG DDS specification. This part contains fundamental functionalities of this specification along with its architecture blocks. Thesis also describes the RTPS protocol functionality. Existing implementations of OMG DDS standard are described at the end of theoretical part. OpenDDS 3.13 implementation is used in practical part of thesis. It is deployed and tested on various platforms. Next part verifies option of securing RTPS data stream using beta version of OMG DDS Security, which OpenDDS 3.13 implementation contains. Secured and unsecured data flows are being compared. Latency of data stream is also important, especially in distributed systems. DDS system, which measures latency of RTPS stream is created in practical part. Latency of this DDS system can be measured in various configurations. Difference of devices’ performance used in measurements can be clearly seen in latency results where the size of data samples is increasing. Differences of measured latency are also recognizable between reliable and unreliable and secure and unsecure RTPS stream. Part of measurements is made between 2 physical devices with and without an attacker. Type of attack is MITM and it captures RTPS flow, which does not belong to attacking machine.
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