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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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Secure applications with microcontrollers
Sobotka, Jiří ; Herman, Ivo (referee) ; Balík, Miroslav (advisor)
This thesis deals with problematics of secure operations of microcontrollers. During long-term use, the microcontrollers can be affected by error or malfunction. The aim of this thesis is to describe the types of errors which can affect processors, cause of creation of these errors and possibilities of preventing malfunctions in microcontrollers. There is many problems connected with operation of microcontrollers, therefore there are many methods to prevent these problems. First part of this thesis deals with description of types of mistakes and with attempts of theirs modelling. Second part of this thesis narrate possibilities of preventing each type of mistake during designing the system or during operation of microcontroller and explaining methods of fault toleration by using redundant circuits in case of hardware fault and by modifying source code in case of software faults. In third part the hazard analytical methods are described. The recognition of events able to damage the system has high importance. The risk analysis takes place during developing and during operation of the system. Fourth part is trying to describe some of the processor testing techniques as main method of finding errors before operating use of microcontroller. Last part attempts to practical draft of testing algorithm for chosen microprocessor and application of one of analytical techniques.
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Acoustical room impulse response database with parametrization of subsequent reverberation
Šiška, Jakub ; Schimmel, Jiří (referee) ; Balík, Miroslav (advisor)
Theoretical part of this bachelor’s thesis discusses description of impulse response, echogram, various methods of impulse response measurement and their comparison. Next part includes describing objective acoustical parameters, remaining energy analysis and its frequency dependent visualization by energy decay relief. Furthermore, existing databases of impulse responses are documented. The practical part consists of realization of own database of impulse responses and various graphical visualizations computed from these impulse responses. In the next part, algorithm for energy decay relief parameterization and modeling of impulse responses is described and realized in Matlab software. In the last part, a listening test is performed to verify impulse response modeling.
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Utilization of MHP platform in DVB-T
Janík, Lukáš ; Balík, Miroslav (referee) ; Kohoutek, Michal (advisor)
This bachelor‘s thesis solves the problem of digital television and set-top boxes, more precisely MHP platform and its use in DVB-T. In the first chapters I talk about analogue terrestrial broadcasting and necessity of transition to digital broadcasting. In addition, you can read about the necessity of the MHP platform implementation as the stable part of the DVB-T. I analyse this platform and describe the pros, cons and possibilities for its use at presen and in the future. I mention the different types of set-top boxes and their main manufacturers. I also describe an application development cycle, from writing the source code, despite testing in the development environment of IRT, respectively Osmosys, until loading to the real set-topbox. I also represent here the practical part of my bachelor‘s thesis, which was the development of chat client for the MHP platform and it allows two users to communicate in real time. This application I tested in the IRT and I uploaded it to the real set-top box. Next I analyze Java programming language, such as the appropriate development language for this platform. I mention the HAVi standard and its relevancy in usage of MHP platform.
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Design and construction of subwoofer - low frequency loudspeaker unit
Holínský, Jan ; Schimmel, Jiří (referee) ; Balík, Miroslav (advisor)
This semestral thesis deals with the design and construction of deep-tone sound units –subwoofers and their use. There are listed descriptions of the individual types of sound systems, the possibilities of connecting the speakers with respect to the changes of the parameters speaker system, and then the design of the baffle with respect to the available materials. Moreover, the disassembled of VUE LMA hybrid solution is described. There are the mathematical relations for calculating the baffle parameters, furthermore there are also available basic programs for the design of the baffles. The purpose of this thesis is to get closer to the problem and to demonstrate the work with the simulation programs, a bandpass filter.
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Universal diagnostic device for accumulators
Němec, Filip ; Lattenberg, Ivo (referee) ; Balík, Miroslav (advisor)
Firstly, this bachelor thesis handles the issues concerning NiCD and NiMh batteries and methods used when charging and discharging. Next segment of the document deals with designing and the actual realization of a device, which can work with these batteries and perform variable tasks,such as charging and discharging battery with adjustable current value, measuring temperature of the battery. Sending data via the serial port,it also implements charging and discharging curve. Device can be operated intuitively using buttons and display. The Device is realized via microcontroller ATMEL.
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Keyword Detection in Speech Data
Pfeifer, Václav ; Makáň, Florian (referee) ; Dostál, Otto (referee) ; Balík, Miroslav (advisor)
Speech processing systems have been developed for many years but the integration into devices had started with the deployment of the modern powerful computational systems. This dissertation thesis deals with development of the keyword detection system in speech data. The proposed detection system is based on the Large Margin and Kernel methods and the key part of the system is phoneme classifier. Two hierarchical frame-based classifiers have been proposed -- linear and non-linear. An efficient training algorithm for each of the proposed classifier have been introduced. Simultaneously, classifier based on the Gaussian Mixture Models with the implementation of the hierarchical structure have been proposed. An important part of the detection system is feature extraction and therefor all algorithms were evaluated on the current most common feature techniques. A part of the thesis technical solution was implementation of the keyword detection system in MATLAB and design of the hierarchical phoneme structure for Czech language. All of the proposed algorithms were evaluated for Czech and English language over the DBRS and TIMIT speech corpus.
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Administration of development documetation over WWW II
Gregárek, Ondřej ; Sysel, Petr (referee) ; Balík, Miroslav (advisor)
Document server is a web application controllable by way of web browser. It is meant to serve for the management of development documentation. The application is divided to the four basic parts: Requirements, Products, Tests and Test Run. The section Requirements serves for inserting requirements for products. Product is produced on the basis of these needs and registered in part Products. Test setting is created in the part Tests according to requirements from the part Requirements. Particular products are then tested. The part Test Run registers records of these tests. These are parts of the application: management of users, connecting supplements to records, printing and exportation of data to different formats, saving history of records, filtration and sorting of entries, etc. All the data is saved in the database MySQL. The application is written in scripting language PHP. Data is presented by template system Smarty. The output is in language XHTML. Cascading style CSS is used to formatting. This work describes development of the application. First it is dealing with the proposal of the database, connection and structure of particular tables. The function of the programme is explained in detail at the same time, which is essential for the correct proposal of the database. The application is based on the database. The selected structure of files and relations of scripts to library functions are shown. The template system and the interface for access of the programme to the database are explained. The most attention is paid to the description of solving important functions of the application, i.e. listing of records, their pagination, filtration, sorting and operation with them: saving, browsing, copying, confirmation and work with history, category and problems by upkeep of consistent tree and export of data to various formats. It is always outlined the problem, the idea of solving and the description of appropriate scripts. Samples of source code are also included for better understanding of complicated algorithms.
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