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Audio codecs and their perceptual quality evaluation
Hudec, Andrej ; Schimmel, Jiří (referee) ; Rajmic, Pavel (advisor)
The bachelor thesis deals with audio codecs and tests to evaluate their listening quality. The thesis offers a description of the properties of human hearing, a brief introduction to the issues of audio coding, types of audio data compression and listening tests. The bachelor thesis also contains a theoretical description of the coding processes of selected audio codecs, evaluation of measuring their computational complexity and evaluation of listening quality of each of them using listening tests. HTML, CSS, Javascript and Python programming languages were used to implement the listening test environment. The audio files examined in the listening tests were obtained using the FFmpeg library.
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Modern coding of speech signals using overcomplete models
Zapletal, Ondřej ; Průša, Zdeněk (referee) ; Rajmic, Pavel (advisor)
The theoretical contents of this thesis are studies of overcomplete models. Those are the models of signals, on which is set for their parametrization more variables, than it's necessary and consequently there's computed so-called sparse solution via iteration algorithms. A goal of this analysis is a selection just of the considerable (sparse) parameters. The theory is based on a linear algebra, vector spaces, bases and so-called frames. The task of the individual project of this thesis is a description and simulation of two speech coders: a classical coder based on linear predictive speech coding and a coder, that's making use of overcomplete stochastic ARMA processes models. A part of their realization is to simulate their decoders and a analyze their reconstruction quality. For their realization there is used MATLAB and an overcomplete models' library (toolbox frames).
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Burst error correction in digital transmissions using Berlekamp -Preparata codes
Pfudl, Tomáš ; Pfeifer, Václav (referee) ; Němec, Karel (advisor)
Bachelor's thesis discusses properties of the systematic convolution codes for error-bursts correction. Berlekamp-Preparata code is a member of this group. Thesis aims at detail description of this code and for picked code designs a codec. Properties discussed at the first part of thesis are used at the second part for picking the code and designing the codec. For designing there are used various methods (programming scripts, simulation model). Codec design is described from properties of communication channel to hardware realization. Each step is exactly interpreted. Whole theoretical design is made in Matlab and for designing the hardware there is used program Xilinx.
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Processing of MP3 files for DSP
Římský, Adam ; Sysel, Petr (referee) ; Herman, Ivo (advisor)
This thesys is concerned with create of compressed .MP3 files and their conversion back into PCM format. I describe individual parts of these operations for their maximal understanding by reader. Next part is generally about properties of DSP, their architecture, computation possibilities and about properties of used product by Analog Devices. In last part is showed implantation of decoder in DSP architecture.
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Protection of data transmission against long error bursts
Malach, Roman ; Lambertová, Petra (referee) ; Němec, Karel (advisor)
This Master´s thesis discuses the protection of data transmission against long error bursts. The data is transmited throught the channel with defined error rate. Parameters of the channel are error-free interval 2000 bits and length of burst error 250 bits. One of the aims of this work is to make a set of possible methods for the realization of a system for data correction. The basic selection is made from most known codes. These codes are divided into several categories and then the best one is chosen for higher selection. Of course interleaving is used too. Only one code from each category can pass on to the higher level of the best code selection. At the end the codes are compared and the best three are simulated using the Matlab program to check correct function. From these three options, one is chosen as optimal regarding practical realization. Two options exist, hardware or software realization. The second one would seem more useful. The real codec is created in validator language C. Nowadays, considering language C and from a computer architecture point of view the 8 bits size of element unit is convenient. That´s why the code RS(255, 191), which works with 8 bits symbols, is optimal. In the next step the codec of this code is created containing the coder and decoder of the code above. The simulation of error channel is ensured by last program. Finally the results are presented using several examples.
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Power line parameters
Kavan, Pavel ; Krajsa, Ondřej (referee) ; Mlýnek, Petr (advisor)
At the beginning is diploma thesis focused on a distribute power line parameters measurement and examination changes of this parameters depending on using of various power line cables. On the basis of measurements is made a transmission channel in Matlab & Simulink, where are executed simulations with power transmission line. The simulated power line is based on measured distribute parameters or physical proportions of cabels. By changing different parts of simulated communication channel is a symbol error rate expressed on the lenght of transmission line.
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Realisation feasibilities of punctured convolutional encoders
Šedý, Jakub ; Zeman, Václav (referee) ; Němec, Karel (advisor)
The aim of this thesis is to bring readers the issue punctured convolutional codes and in the design and verification of the functionality of the codec as a separate electronic system. The thesis is divided into four main chapters. The first three chapters deal with design and implementation of individual blocks of the codec and the subsequent verification of these blocks. The fourth and last chapter deals with the design and implementation of the codec as a separate electronic system.
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Realization of OFDM coder for DVB-T system
Zelinka, Petr ; Maršálek, Roman (referee) ; Frýza, Tomáš (advisor)
The contents of this thesis is a delineation of the European Standard ETSI EN 300 744 for terrestrial digital video broadcasting (DVB-T) and a description of created OFDM coder and decoder for baseband signal transmission in 2K mode without error correction capabilities. The proper function of both devices is verified by means of Matlab simulations and practically implemented into Texas Instruments’ digital signal processor TMS320C6711 using Starter Kits.
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Measurement of DVB-T transmission over simulated fading channel
Vašut, Jakub ; Kratochvíl, Tomáš (referee) ; Štukavec, Radim (advisor)
The goal of this bachelor’s thesis is to study basic functional elements of coder and modulator of standart DVB-T. Another goal is to study documentation of DVB-T modulator DTA-110T and ASI/SDI adapter DTA-145 by DekTec. Also is described software channel simulator DTC-305 and parameter settings of simulated fading channel. Fading channels are measured and assigned their effect on quality of received DVB-T signal.
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