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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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Simulation of the HVS characterstics in Matlab
Ševčík, Martin ; Slanina, Martin (referee) ; Kratochvíl, Tomáš (advisor)
In theoretical part Diploma thesis deals with the model of human vision HVS (Human Visual System), which can be used for image quality assessment in TV technique area. It has been described calculations of selected JND (Just Noticeable Difference) metrics, used in evaluation of HVS. In practical part of the thesis it has been suggested and realized simulation model in Matlab, which may be used for evaluation of three JND metrics from color and grayscale images and evaluation in spatial a frequency domain. Results of JND models have been compared to another objective image quality evaluation metrics (MSE, NMSE, SNR and PSNR). For interpretation of dependencies it has been used images with different defined content.
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Program for evaluating image quality using neural network
Šimíček, Pavel ; Kratochvíl, Tomáš (referee) ; Slanina, Martin (advisor)
This thesis studies the assessment of picture quality using the artificial neural network approach. In the first part, two main ways to evaluate the picture quality are described. It is the subjective assessment of picture quality, where a group of people watches the picture and evaluates its quality, and objective assessment which is based on mathematical relations. Calculation of structural similarity index (SSIM) is analyzed in detail. In the second part, the basis of neural networks is described. A neural network was created in Matlab, designed to simulate subjective assessment scores based on the SSIM index.
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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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Digital television broadcasting according to standard DVB-H
Pospíchal, Martin ; Prokopec, Jan (referee) ; Kratochvíl, Tomáš (advisor)
The bachelor work deals with problems of digital broadcast based on the standard DVB-H. It contains of the theoretic part and than there is the experimental part. The theoretic part compares the standard DVB-T with DVB-H in the introduction. Then comes after the theoretic explanatinon of the source coding of the picture and the standard for the coding the sound, channel coding and the modulation of the signal. Then it describes a scheme for metering the norm of DVB-H composed of a laboratory qauqing apparatuses and its brief describtion. Then comes after the description of the several metered and biased parameters and its impression on the quality and level of the recieved signal. The experimental part deals with the metering of the several parameters, that contains the description of the laid metering constellation diagrams, tables of the measured values, graphics dependences and evaluation of the concrete metering. The metering deals with the influence of the amplitude of the screened signal, phasic error, suppression carrier, amplitude imbalance, convolution code, guard interval and with the using the several modulations on a bit error rate BER, modulation error rate MER (S/N), the quality and the level of the received signal for the several TV channels.
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Design and making of low-frequency power amplifier in class AB
Dušek, Martin ; Kratochvíl, Tomáš (referee) ; Brančík, Lubomír (advisor)
In this bachelor thesis I am occupied with low frequency amplifiers, theirs important parameters, classes and with integrations end-level. Next I am occupied with miscellaneous types of preamplifiers and additional circuits. There are simulated schemes of corrective preamplifier, protections scheme and high power amplifier in PSpice software in this thesis. These schemes and next additional modules are connected with DPS. This thesis contains result of measurement and photo functional sample.
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Design of switching low-frequency power amplifier
Janáč, Josef ; Kratochvíl, Tomáš (referee) ; Brančík, Lubomír (advisor)
This bachelor project maps out switching technologies used in LF power electronics and gained information was consequentially used to design switching lf power amplifier as independent unit. Content of design is LF power amplified level, working on switching technology principle. Correction pre-amplifier with possibility of adjusting volume, balance h/l frequency and switching power supply is content as well too. Next part of project is familiarization s design program Eagle and optimizing program for switching power supply PXLS expert and creating constrictive basis for complete device. Last part of project is basically activation all functional part of device in one unit. Than measurement basic parameters on created functional device, graphical elaborating measurement-gained values and confrontation with catalog values. Conclusion of this project is evaluation achieved results in compare with supposed result of project.
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System for Imaging of the Monochromatic Pictures in the Pseudo Color
Kaděrka, Petr ; Kratochvíl, Tomáš (referee) ; Říčný, Václav (advisor)
This diploma thesis treats the possibilities of the black-white picture depiction in pseudo colors (Pseudocolor). The individual methods, software or hardware are described there and the detailed block scheme of the system Pseudocolor is suggested. The block scheme is created on the basis of gained theoretical knowledge. In the thesis, individual functional blocks of the scheme are described and their circuit designs are realized. Some of the functional blocks are simulated by the PSpice program and accompanied by corresponding signal process data. The suitable choice of the active and passive components is performed, from which the general integration of the system Pseudocolor is made. All the source materials for the realization of the device are given there – double-sided drawing of the printed circuit, layout and specification of the components.
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Robot's end effectors for manipulation
Kratochvíl, Tomáš ; Kubela, Tomáš (referee) ; Flekal, Lukáš (advisor)
This bachelor thesis deals with the robot’s end-effectors for manipulation. The first part describes the basic types of industrial robots and manipulators. In another chapter are examples for what applications are used robotic applications. In depth are analyzed the elements of end effectors. Another section defines the methodology for designing end-effectors and subsequently demonstrated in the sample application. The last chapter briefly discusses the possible future development of end effectors.
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