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Impedance tube for measuring sound absorption coefficient and transmission loss coefficient
Hodinka, Tomáš ; Balík, Miroslav (referee) ; Skvaril, Šimon (advisor)
The goal of this thesis is the design and manufacture of the mechanical and electrical components of the impedance tube. The impedance tube is a tool used in laboratories, that has its parameters dictated by norms. On one side of this enclosed airtight tube is a speaker, and on the other the measured material. By switching some additional parts, the tube is capable of measuring not only the acoustic absorption, but also sound penetration. Impedance tube is made, so that it is robust, easy to manipulate and use, and easy to store. The designed impedance tube can measure the sound penetration of any material, that is up to 50mm in thickness, and the acoustic absorption of materials that are up to 120mm in thickness. Parts of the tube, that are directly welded to the tube itself are made of the same metal that the tube itself is, and the speaker enclosure is made from plywood. Along with the assembly of the impedance tube, a complete and detailed drawing documentation for future recreation is added, along with a suitable amplifier and all peripherals necessary for measurements.
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Microphone Array for Estimation of Direction of Arrival of Sound
Kubišta, Ladislav ; Balík, Miroslav (referee) ; Schimmel, Jiří (advisor)
This bachelor's work describe detection of direction receiving sound by analizing of the sound. Work is based on methods of time delay estimation. Programmed algorithm of estimation direction works on cross–correlation and some selected cross–correlation methods. Results of measuring, as programming sound, so sound recorded in laboratory conditions and real enviroment, are mentioned in conclusion. All calculations were done by platform Matlab
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Power supply and protection circuits for 6-channel audio amplifier
Kryška, Vojtěch ; Balík, Miroslav (referee) ; Hanák, Pavel (advisor)
This bachelor thesis deals with designing protection circuits for 6 channel audio amplifier. Created circuits provide AC voltage filtering, current peak limitation after switching on, delayed speakers connection for eliminating crackling, automatic shut down in case of overheath, LED indication of failure and waking up from standby mode. Created design focuses on keeping all channels grounds unconnected with each other for eliminating ground loops.
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Room acoustic modeling
Bernát, Michal ; Balík, Miroslav (referee) ; Míča, Ivan (advisor)
This Master's Thesis deals with geometric modeling methods and theirs implementation in Octave (Matlab), which is ideal for the practical realization. The first part of the thesis is focused on a very simplified image source method, which is able to calculate and render the 2D impulse response of rectangular rooms. The next part is aimed on~the same method, but extended by three-dimensional simulation of polyhedral prism-shaped rooms. There is both an explanation of theoretical and mathematical aspects and a~documentation of the implemented source code. Extended image source method is able to generate sound representation of impulse response characteristics, and use it for auralization, which is achieved by using convolution of both the input sound source and the calculated impulse response. At the end there are two practical examples for both methods with explanatory illustrations.
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Programming of processors in 32- or 64-bit operation systems
Rášo, Ondřej ; Kyselý, František (referee) ; Balík, Miroslav (advisor)
Main topic of this thesis is Win32 application programming interface and symbolic instructions programming language. It can be divided into four parts. First part sums the basics of 32-bit programming in symbolic instructions language in Windows. Second part describes the Win32 resources for computer intercommunication. Third part presents, describes and comments selected problems in symbolic instructions language.Last part covers a creation of an example application. This application and its parts will be the content of computer exercises in VUT Brno FEEC subject Počítače a jejich periferie.
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Features and testing of mobile devices with Android OS
Ružička, Silvestr ; Malina, Lukáš (referee) ; Balík, Miroslav (advisor)
The work deals with creating applications for the Android OS, gathering information on mobile device and testing of computing power. In this theisis we talk about the history, development and architecture of the Android OS. Described here the application development fo Android OS. Process The output of this work is an application for finding information on the mobile device and to test the computational performance.
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Multi-channel Methods of Speech Enhancement
Zitka, Adam ; Balík, Miroslav (referee) ; Smékal, Zdeněk (advisor)
This thesis deals with multi-channel methods of speech enhancement. Multichannel methods of speech enhancement use a few microphones for recording signals. From mixtures of signals, for example, individual speakers can be separated, noise should be reduced etc. with using neural networks. The task of separating speakers is known as a cocktail-party effect. The main method of solving this problem is called independent component analysis. At first there are described its theoretical foundation and presented conditions and requirements for its application. Methods of ICA try to separate the mixtures with help of searching the minimal gaussian properties of signals. For the analysis of independent components are used different mathematical properties of signals such as kurtosis and entropy. Signals, which were mixed artificially on a computer, can be relatively well separated using, for example, FastICA algorithm or ICA gradient ascent. However, difficult is situation, if we want to separate the signals created in the real recording enviroment, because the separation of speech people speaking at the same time in the real environment affects other various factors such as acoustic properties of the room, noise, delays, reflections from the walls, the position or the type of microphones, etc. Work presents aproach of independent component analysis in the frequency domain, which can successfully separate also recordings made in the real environment.
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Administration of development documetation over WWW I
Kolář, Miroslav ; Sysel, Petr (referee) ; Balík, Miroslav (advisor)
Master`s thesis is based on the assignment of company Honeywell to create integral system for saving and management of development documentation. Designed system will introduce data warehouse with transparent display of documents being connected with development of customer’s requirements, products and tests, test runs. Solution consists of two parts: A – Requirements and Products and B – Tests, Test runs and Person, whereas Master`s thesis deals with the part B. For system creation utilities of following programming languages were used HTML, PHP, JavaScript and database system MySQL. In the first phase was designed database structure (tables and relations between them). Except that was designed structure for authorization algorithm and integral concept of whole application was created. The second phase is realization. At first are created supporting algorithms. It is servicing database by functions, uniform displaying results from database and authorized access of users to the application. Further data library for integral display data forms, based on used template system Smarty and other libraries, f.e. attribution of the files to records in SQL tables. Important part was implementation of designed database system and related programs. In Tests and Test runs there is user interface established and individual relations between them. According to assignment all fundamental programs were designed together with support instruments. Individual source files are saved in transparent structure of folders, so this structure is possible to apply on any computer, where are installed programs to web hosting. The result of Master`s thesis is then integrated progress report together with functional source codes.
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