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USB Ultrasound Imaging System
Kratochvíl, Tomáš ; Mézl, Martin (referee) ; Harabiš, Vratislav (advisor)
This master thesis deals with development and construction of ultrasound diagnostical system with USB interface. The main task is to study current usage of A mode ultrasound systems and methods of their construction. Following with own design of A mode ultrasound system with usage of assigned Olympus ultrasound transducer.
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Simulation of the DVB-T digital modulation in Matlab
Málek, Pavel ; Říčný, Václav (referee) ; Kratochvíl, Tomáš (advisor)
Digital Video Broadcasting (standard DVB) is a system for transmission of the television signals in the digital form. There are used a various types of modulations in this system as QPSK modulation is used in the systems of satellite video broadcasting DVB-S (Satellite) and M-QAM modulations in the cable transmitting DVB-C (Cable). This paper mainly deals with system of the terrestrial digital video broadcasting DVB-T (Terrestrial), where OFDM modulation is used. This type of signal processing is more resistant to the distortions caused by multipath transmitting, which is main problem in the DVB-T. Matlab application, which can simulate digital modulation and demodulation of the transmission signals in the DVB-T, is created in this thesis. The models of the transmission channel is inserted between structures of modulator and demodulator. The user of this application can set the parameters of the broadcasting (e.g. constellation, OFDM mode, guard interval insertion) and the type of distortions (additive noise, reflected and delayed signals). By calculation of the channel bit error rate (BER) user can study influences of broadcasting parameters to the quality of transmission.
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Video and Data Services Quality in the Future Broadband Multimedia Systems and Networks
Kufa, Jan ; Hudec, Róbert (referee) ; Fliegel,, Karel (referee) ; Kratochvíl, Tomáš (advisor)
Téma doktorské práce je zaměřeno na analýzu zpracování signálů v širokopásmových multimediálních sítích a systémech budoucnosti, kde se předpokládají systémy s ultra vysokým rozlišením (UHDTV), vysokým snímkovým kmitočtem (HFR) a stereoskopické systémy (3D). Tyto systémy budou umožňovat vysoce účinnou zdrojovou kompresi obrazu, zvuku a dat a také jejich vysoce účinný přenos, a to jak při volném vysílání (např. DVB-T2), tak ve službách placené televize (např. IPTV). Cílem práce je analýza a vyhodnocení kvality obrazu a služeb v těchto systémech na základě objektivních metrik a subjektivních testů. Práce se dále zaměřuje na analýzu vnímané kvality u stereoskopické televize, kódovací účinnost moderních stereoskopických enkoderů a vlivu sekvencí na uživatelský komfort.
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DSP audio processor for laboratory measurements
Struhelka, Michal ; Stifter,, Jiří (referee) ; Kratochvíl, Tomáš (advisor)
This project deals with the subject of laboratory preparation for low-frequency and audio electronics. It is used DSP audio processor with integrated ADCs and DACs converters ADAU1701 from Analog Devices. Also, Atmel microcontroller with a connected graphic LCD display and buttons is used for adjusting DSP. The work presents the complete instructions of the laboratory project with a model protocol.
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Audio speaker system with baffle made from alternative materials
Hüttl, Ondřej ; Schimmel, Jiří (referee) ; Kratochvíl, Tomáš (advisor)
This thesis firstly consists of an analysis and a description of materials suitable for construction of loudspeaker enclosures and a design of the loudspeaker system with the enclosure made of a synthetic stone. Electro – acoustics drivers have been described with a focus to a frequency range, a principle and a construction for an explanation of their function. Drivers based on electrodynamic principle have been described closely. An analysis of materials used for the loudspeaker enclosure production has been done and tradicional and alternative materials have been described as well. Specific modulus, density and stiffness have been taken as an objective evaluative criterion. An evaluation indicates appropriate properties of plastic, aluminum and stone based materials. The function and kinds of loudspeaker enclosures have been described. The function, properties and design of a vented box loudspeaker system have been described closely. The last part of this thesis is individual design of a two-way vented box loudspeaker system with the enclosure made of synthetic stone. A simulation of a driver behavior built in the enclosure and compensation circuits and crossovers design and simulation have been done. The enclosure has been designed with high stress to minimize negative effect of the enclosure to the final sound quality.
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Hybrid headphone amplifier for the high-end listening and performance
Čacký, Adam ; Šotner, Roman (referee) ; Kratochvíl, Tomáš (advisor)
This bachelor´s thesis describes the design of a high quality small portable headphone amplifier for dynamic headphones. Part of the work is theoretical assumptions for the optimal design and implementation of peripheral involvement, comparing the properties of components used and the resulting parameters of modeled device. Analyses of the electrical quantities of the circuit created in simulation software are enclosed.
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Class D 2.1 audio amplifier for laboratory measurements
Děcká, Klára ; Polák, Ladislav (referee) ; Kratochvíl, Tomáš (advisor)
This semestral thesis deals with a draft and construction of the design of an class D audio amplifier with pulse width modulation. The resulting design consists of a supply protection, an active crossover and the output power stage itself. The amplifier is made in 2.1 configuration, the amplifier for mid/high audio frequency drives 2 × 30 W output into a 8 load, subwoofer drives 1 × 100 W into a 2 load. The control centre of the whole application is an integrated circuit TPA3116D2 by Texas Instruments company. The resulting audio amplifier will be used as a device for laboratory measurements.
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Analysis of the transmission in the mobile digital audio broadcasting
Kresta, Daniel ; Ulovec,, Karel (referee) ; Kratochvíl, Tomáš (advisor)
This thesis deals with an analysis of a system called Digital Audio Broadcast and describes its mathematical model created in MATLAB program. In the first part basic blocks of a transmitter and a receiver are analyzed along with their principles. Then different types of transmission channels for static, portable and mobile receivers are described. The second part contains description of the DAB mathematical model itself. Individual blocks are described in the order of the DAB signal path, from the transmitter through the transmission channel to the receiver side. In this part the graphical user interface is also described. In the final part the results of experimental measurements and simulations are presented.
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Class AB stereo audio power amplifier with electron tubes
Herbrych, Vojtěch ; Šotner, Roman (referee) ; Kratochvíl, Tomáš (advisor)
Bachelor thesis deals with design and create construction drawings of audio amplifier using vaccum tubes with output power 20 W/4 and works in class AB. At least two inputs are included for mobile, computer and others. The device includes 2-band preamplifier with basic adjustment (bass and treble). For different channel volume is included balance adjustment. There is an audio-level indicator with „magic-eye tube“. This part of bachelor thesis contains theoretical explanation, design of amplifier´s schematic and design drawings.
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Measurements of the DVB-T Digital Television Receiver Parameters
Komenda, Jan ; Štukavec, Radim (referee) ; Kratochvíl, Tomáš (advisor)
The diploma thesis is focused on the measurement of selected parameters of the digital TV receiver DVB T, set top box. In the introductory part the work briefly deals with the theory of compression and transmission of the digital TV signal. Main part of the thesis contains detail information about individual circuits of the selected set top box Humax F3-FOX T and the results of measurements of individual parameters obtained from the available measuring devices. The final part of the thesis deals with the design changes necessary for creation of the external output for the signals and also with the methodology of the measurement.
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