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Frequency measurement
Milota, Martin ; Havránek, Zdeněk (referee) ; Čejka, Miloslav (advisor)
The theme of this thesis is presentation of the CompactRIO platform by National Instruments with its range of hardware and the possibility of using this platform for the frequency measurement of analog signals. The result of this thesis is software equipment for this device focusing on the frequency measurement of analog signals and experimental verification of posibilities of a specific configuration of this platform in the range of measurable frequencies.
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Influence of physical load to electrical activity of muscles
Kadeřábek, Jan ; Sekora, Jiří (referee) ; Kolářová, Jana (advisor)
This bachelor’s thesis describes influence of physical load on electrical activity of muscles. In each of bachelor’s thesis chapters are analyzed questions of measurement EMG signals and their elaboration, include statistic attestation of influence physical load on electrical activity of muscles. EMG signals were received from group of 10 students and in program acqKnowledge, were taken off parameters for statistic elaboration. In created program were due to time and frequency analysis calculated parameters of EMG records, which can also describe influence of physical load. Accomplishments of this project are the tables with measured data, their graphs, statistics attestation of influence physical load on electrical activity of muscles and program, which can do time and frequency analysis of measured records. On significance level 10% was verified hypothesis, that physical load influence electrical activity of muscles.
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Identification of pauses in noisy speech signal
Kepák, Petr ; Míča, Ivan (referee) ; Smékal, Zdeněk (advisor)
The basic problem of speech is a complete separation of the natural noise which arise from correct articulation of voiced and unvoiced consonants from noise and disturbance environment. Objective of this master’s thesis is to find an effective method that could identify the pauses without speech activity, which can identify the properties of noise and disturbance. Once the noise is correctly identified, it is already possible to use different methods for its removal. The master’s thesis describes two methods of pauses identification. These methods are programmed in Matlab and tested on nine speech recordings. Methods analysis of the results was performed using the ROC (Receiver Operating Characteristic) curves. In the end are summarized results analysis of created methods.
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Visualization of vocal cords movement
Kutálek, Libor ; Sekora, Jiří (referee) ; Rozman, Jiří (advisor)
The aim of this work is to clarify the function of the vocal cords and get familiarized with their investigative methods. In this work we find possible solutions to the peripheral device to illuminate the rapidly vibrating vocal cords using an LED that is less energy exacting than conventional halogen lamps. Then there are solved the problems of processing, signal filtering and finding the natural frequency of vibration of the vocal cords.
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Analysis of sleep EEG signal
Ježek, Martin ; Kozumplík, Jiří (referee) ; Rozman, Jiří (advisor)
Cílem této práce byl vývoj programu pro automatickou detekci arousalu v signálu spánkového EEG s použitím metod časově-frekvenční analýzy. Předmětem studie bylo 13 celonočních polysomnografických nahrávek (čtyři svody EEG, EMG, EKG a EOG), tj. celkově více než 100 hodin záznamu. Jednalo se o část dat z dřívějších výzkumných prací expertní lékařky v problematice spánku Dr. Emilie Sforzy, Ženeva, Švýcarsko, která rovněž poskytla základní hodnocení těchto dat. V záznamech bylo celkem označeno 1551 arousal událostí. Pro usnadnění výběru konkrétní metody časově-frekvenční analýzy byla následně vytvořena sada nástrojů pro vizualizaci jednotlivých signálů a jejich různých časově-frekvenčních vyjádření. S ohledem na závěry vizuální analýzy, charakter signálu EEG a efektivitu výpočetních metod byla pro analýzu vybrána waveletová transformace s mateřskou vlnkou Daubechies řádu 6. Jednotlivé svody EEG byly dekomponovány do šesti frekvenčních pásem. Z takto odvozených signálů a signálu EMG byly následně stanoveny ukazatele možné přítomnosti události arousalu. Tyto ukazatele byly dále váhovány lineárním klasifikátorem, jehož hodnoty vah byly optimalizovány pomocí genetického algoritmu. Na základě hodnoty lineárního klasifikátoru bylo rozhodnuto o přítomnosti události arousalu v daném svodě EEG – arousal byl detekován, jestliže hodnota klasifikátoru překročila danou mez na dobu více než 3 a méně než 30 vteřin. V celém záznamu pak byl arousal označen, byl-li detekován alespoň v jednom ze svodů EEG. Následně byly odvozeny míry senzitivity a selektivity detekce, jež byly rovněž základem pro stanovení fitness funkce genetického algoritmu. Pro učení genetického algoritmu byly vybrány první čtyři záznamy. Na základě takto optimalizovaných vah vznikl program pro automatickou detekci, který na celém souboru 13 záznamů dosáhl ve srovnání s expertním hodnocením míry senzitivity 76,09%, selektivity 53,26% a specificity 97,66%.
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HP89410A User Interface
Neužil, Jan ; Caha, Luděk (referee) ; Beneš, Petr (advisor)
The aim of this thesis was to develop user interface in LabVIEW to make typical measurements with spectral analyzer HP89410A There is introduced the theory of operation of an analogue heterodyne and a digital FFT spectral analyzer. It is explained the background of the Fast Fourier Transform. There are discussed the key settings in measuring with FTT analyzer, like window function, bandwidth, number of frequency points, or the averaging. Further is described the program, which was developed for measuring frequency characteristic by white noise and by stepped measurement. It was also made a module for measuring Signal to Noise Ratio and module for Total Harmonic Distortion. In the last part of this thesis are shown the results of processed exemplar measurements.
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Alternative methods and algorithms for flame detection
Kozubík, Kamil ; Dřínovský, Jiří (referee) ; Frýza, Tomáš (advisor)
This master’s thesis deals with flame detection methods. The purpose of the project was to create a flame detector, which uses the alternative method of flame detection. The introduction of this thesis gives the summary overview of the existing methods for flame detection. Further, the existing flame detectors and their applications are described. Two alternative algorithms for flame detection which are based on the digital signal analysis were realized on the PC. Flame detector, which utilizes the digital analysis of audio signal, was realized on 8 bit microcontroller Atmega128 and achieved results are presented.
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Speech Recognition (digit)
Kantar, Martin ; Minář, Petr (referee) ; Matoušek, Radomil (advisor)
The aim of this diploma thesis is to explain what speech is and what are its constituents. I mention commonly used methods which are used for preparation of signals which we use for recognition. Schematic examples show principles of current recognizers of speech, their advantages and disadvantages. I made speech recognition program for 0-9 numerals in Matlab for neural nets learning.
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Development of mobile application for musicians
Novotný, Miroslav ; Pavlíčková, Jarmila (advisor) ; Kutišová, Magda (referee)
The aim of this bachelor's thesis is to design and develop an Android application for musicians. The theoretical part, is conceived as an introduction to the theory of sound. Firstly, I describe the architecture of Android and the individual components that make it up. There are subsequent chapters exploring the sound from its inception, through the process of converting to digital form, to a description of the individual interfaces for the recording and processing from within the environment of an Android system. The practical part, is devoted to designing and developing an application that serves as a tool for practicing playing a musical instrument. The application consists of various features such as: tuner, metronome and an EarTrainer. To understand the component of a tuner it has been necessary to study a theory needed to support the main functionality of calculating the frequency of the recorded audio signal. For this reason, this thesis is also a theoretical introduction to the Fourier transformation. The last part of this thesis is focusing on how the tuner compares with the calculation accuracy of other competitors. Finally, The application was published for the Google Play store.
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Observation of HF Cathode and ARC Root Inside Cutting Plasma Torch
Šonský, Jiří ; Gruber, Jan
Electric arc and a cathode of a cutting plasma torch was observed through fused silica window in a specially modified nozzle. Sample rate of used high-speed camera was up to 120 kHz, sufficient for detecting high-frequency fluctuations in arc plasma intensity, produced mainly by current ripple. Fluctuations were examined up to 60 kHz by Fast Fourier Transformation (FFT). Increased cathode material loss at start-up and shut-down phase of the plasma torch was observed. At start up phase, large number of small particles are ejected from the cathode. After electric current shuts down, large droplets of molten material are usually detected.
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