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Laboratory waveform generator based on DDS
Kret, Tomáš ; Povalač, Aleš (referee) ; Šebesta, Jiří (advisor)
The project concerns about design of function generator based on direct digital synthesis, its software and hardware realisation. It solves generating functions depended on time like sine, triangle and square with variable duty cycle, burst and other functions of frequency sweep, FM and PWM modulation. Next goal is to display user interface on graphic LCD display and to control microcontroler pheripheries of AVR.
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DDS waveform generator
Čada, David ; Tejmlová, Lenka (referee) ; Šebesta, Jiří (advisor)
This project deals with design and realization of the function generator using a direct digital synthesis. This work solves hardware and software of the function generator, which is capable to generate following shapes: sine, trialngle, square with variable duty cycle, pulse width modulation, frequency shift keying, pulse, linear frequency sweeping, logaritmic frequency sweeping, and programable signals of a serial peripherial interface.
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Laboratory waveform generator based on DDS
Kret, Tomáš ; Povalač, Aleš (referee) ; Šebesta, Jiří (advisor)
The project concerns about design of function generator based on direct digital synthesis, its software and hardware realisation. It solves generating functions depended on time like sine, triangle and square with variable duty cycle, burst and other functions of frequency sweep, FM and PWM modulation. Next goal is to display user interface on graphic LCD display and to control microcontroler pheripheries of AVR.
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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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Laboratory Function Generator
Trnkus, Andrej ; Kubíček, Michal (referee) ; Šebesta, Jiří (advisor)
This thesis deals with the design of function generators based on direct digital synthesis. It examines software and hardware realisation of a generator of sinus, triangle and rectangle shaped signal, frequency sweep, pulse-width modulation and data transfer after the SPI data bus. It also focuses on the user interface display on an LCD display, control by a rotational encoder and the buttons of the microcontroller periphery of an AVR class.
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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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Digital Mixing Console
Přibyl, Libor ; Krajsa, Ondřej (referee) ; Kubánek, David (advisor)
The presented work deals with the issue of digital mixing console. The main focus is on the design of sub-circuits for the digital mixer and the construction into the 19 "rack unit. The thesis presents a detailed description of individual parts and their use. Thesis also includes complete device designs, including a power supply and additional circuits.
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Programmable signal generator connected via USB
Patočka, Lukáš ; Krajsa, Ondřej (referee) ; Lattenberg, Ivo (advisor)
The subject of this thesis is design and construction of a periodic signal generator prototype. The generator will use Atmel XMEGA128A4U microcontroller with computer control managed via USB interface. The thesis contains general solutions to the problem of generating signals with a special focus on utilization of DA converter – digital synthesis and reconstruction of the signal from DA converter output to continuous signal. The thesis further deals with implementation of the USB layer using two libraries (LUFA library on microcontroller side and LubUsbDotNet library on computer side). The final solution will include DC step-up converter for signal peak amplitude assessment and summing amplifier for adding the DC voltage to the output signal. The application will allow for generating signals of various shapes including user-defined ones. These signals will be displayed in the actual application window. There, users will be allowed to create user-defined signal in easy-to-use GUI or load it directly from a file.
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Audio ADC and DAC for laboratory measurements
Raszka, Dan ; Frýza, Tomáš (referee) ; Kratochvíl, Tomáš (advisor)
This paper describes the design of a laboratory equipment to demonstrate the influence of the sampling frequency and quantization errors on converter. Part of this work is to select appropriate ADC and DAC along with control microprocessor. The proposal contains other functional blocks such as analog input and output filters, LCD display and controls. It deals also with the design of software solutions to control and signal processing.
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Evaluation Of Influence Of Anti-Aliasing And Reconstruction Filters On Digital Predistortion
Král, Jan
Present wideband and spectrally-efficient communication systems require linear transmitters. As power amplifiers are naturally nonlinear, the linear transmitter is often achieved by application of a digital predistorter (DPD). DPDs require system bandwidth to be higher than communication bandwidth. We provide an evaluation of influence of the reconstruction and anti-aliasing filter on quality of predistortion process. Our results show that the generally accepted rule is too demanding and the actual required filters bandwidth is lower. This has direct impact on required sampling rates of system converters.
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