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Noise Analysis of Basic Circuits for Analog Signal Processing
Humpolíková, Michaela ; Sládok, Ondřej (referee) ; Kubánek, David (advisor)
The cause of noise in analog circuits is a problem of quality in output signals. There are many reasons of its occurrence, noise is caused by components connected into the circuit, and the assembly itself. This bachelor thesis summarizes the theoretical knowledge about noise analysis. Noise measurement in circuits can now be calculated with PSpice, the results are used for the design of low noise circuits. In the contained practical analysis of the circuits were achieved the results for the suitable designing of low noise circuits.
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Neural Network Based Edge Detection
Janda, Miloš ; Žák, Pavel (referee) ; Švub, Miroslav (advisor)
Aim of this thesis is description of neural network based edge detection methods that are substitute for classic methods of detection using edge operators. First chapters generally discussed the issues of image processing, edge detection and neural networks. The objective of the main part is to show process of generating synthetic images, extracting training datasets and discussing variants of suitable topologies of neural networks for purpose of edge detection. The last part of the thesis is dedicated to evaluating and measuring accuracy values of neural network.
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Utilization of light polarization when filtering the optical signal
Alexa, Jan ; Vlček, Čestmír (referee) ; Wilfert, Otakar (advisor)
This master thesis deals with the possibility of separation of useful signal from noise using polarization of laser radiation. This thesis is structured into 5 thematic units. The first unit is focused on laser radiation and its properties. The second part contains a deeper focus on the polarization of radiation, its description and the possibilities of measuring the polarization states. The third part of the thesis is devoted to the design of the measuring chains and identification of used elements. Chapter four contains measurement of status of the polarization and its results. The last chapter analyzes particular measuring chains outputs according to their spectral characteristics.
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Multimedia support of the course BSIS
Pasečný, Jan ; Šebesta, Vladimír (referee) ; Sigmund, Milan (advisor)
This paper takes aim at creating a consistent form of study materials, supplemented with illustrative examples, for Signals and systems subject. The thesis starts with basic characteristics of acoustic, image, biological and communication signals. Characteristics of linear signals and AD&DA conversion has been added to the next part and to complete the submission, discrete signals follow. Diploma thesis as a whole contains basic theoretical description of problematics, which it tries to supplement with interesting examples, connections, graphs and matlab scripts for illustrative presentation of mentioned problematics.
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Improving Robustness of Speaker Recognition using Discriminative Techniques
Novotný, Ondřej ; Ferrer, Luciana (referee) ; Pollák, Petr (referee) ; Černocký, Jan (advisor)
Tato práce pojednává o využití diskriminativních technik v oblasti rozpoznávání mluvčích za účelem získání větší robustnosti těchto systémů vůči vlivům negativně ovlivňující jejich výkonnost. Mezi tyto vlivy řadíme šum, reverberaci nebo přenosový kanál. Práce je rozdělena do dvou hlavních částí. V první části se věnujeme teoretickému úvodu do problematiky rozpoznávání mluvčích. Popsány jsou jednotlivé kroky rozpoznávacího systému od extrakce akustických příznaků, extrakce vektorových reprezentací nahrávek, až po tvorbu finálního rozpoznávacího skóre. Zvláštní důraz je věnován technikám extrakce vektorové reprezentace nahrávky, kdy popisujeme dvě rozdílná paradigmata možného přístupu, i-vektory a x-vektory. Druhá část práce se již více věnuje diskriminativním technikám pro zvýšení robustnosti. Techniky jsou organizovány tak, aby odpovídaly postupnému průchodu nahrávky rozpoznávacím systémem. Nejdříve je věnována pozornost předzpracování signálu pomocí neuronové sítě pro odšumění a obohacení signálu řeči jako univerzální technice, která je nezávislá na následně použitém rozpoznávacím systému. Dále se zameřujeme na využití diskriminativního přístupu při extrakci příznaků a extrakci vektorových reprezentací nahrávek. Práce rovněž pokrývá přechod od generativního paradigmatu k plně diskriminativnímu přístupu v systémech pro rozpoznávání mluvčích. Veškeré techniky jsou následně vždy experimentálně ověřeny a zhodnocen jejich přínos. V práci je navrženo několik přístupů, které se osvědčily jak u generativního přístupu v podobě i-vektorů, tak i u diskriminativních x-vektorů, a díky nim bylo dosaženo významného zlepšení. Pro úplnost jsou, v oblasti problematiky robustnosti, do práce zařazeny i další techniky, jako je normalizace skóre, či více-scénářové trénování systémů. Závěrem se práce zabývá problematikou robustnosti diskriminativních systému z pohledu dat využitých při jejich trénování.
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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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Precision audio preamplifier for headset measurement
Šimek, Michal ; Balík, Miroslav (referee) ; Hanák, Pavel (advisor)
This thesis deals with microphone and headphone preamplifier for microtelephone and headset. The design shall meet the electrical interface requirements set out in ITU-T Rec. P.381(08/2012). The design includes a voltage converter, microtelephone bias and both a battery and an external power supply. In this work is also described the design of printed circuit board and the solution of a low noise in the whole circuit. The aim of this thesis is to design, built and embed the laboratory fixture into a metal box. Finally, measure the product on an APx525 audio precision analyzer.
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System for precise dynamic measurement of bridge sensors
Čech, Jonáš ; Kolka, Zdeněk (referee) ; Kubíček, Michal (advisor)
This master’s thesis deals with design of measurement system for dynamic measurement of bridge sensors. After a short theoretical part, the own concept is introduced. System can provide sampling rate up to 250 kSa/s with 24-bit resolution. The maximum number of samples is about one and a half milion. At first, the design of analog part was made, in this phase of design the digital part is based on evaluation board with ARM Cortex-M7 and external memory. After final choice of appropriate ICs, the analog and digital part will be integrated into one PCB.
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ECG noise generator
Mikuláš, Karol ; Kozumplík, Jiří (referee) ; Hrubeš, Jan (advisor)
Real ECG signal contains undesirable artifacts arising from its capture. Due to loss of diagnostically useful information in the noise signal and followed by the filtering the signal is important to know the characteristics, the most common symptoms and causes, to avoid or minimize the noise ECG signal. ECG noise generator is an educational program designed to serve the learning methods of filtering the noise signal. The user program can verify the effectiveness of the chosen method and the extent of deformation of the useful signal. The program includes basic types of artifacts, such as powerline interference, baseline wander, drift, impulse noise, myopotentials and change of baseline wander of ECG signal, which can be prepared noise signal from a database or other signal selected by the user.
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