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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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QAM Modulator
Duffek, Luděk ; Kubánek, David (referee) ; Číž, Radim (advisor)
The thesis focuses on consideration of possible ways how to realize multi-state modulators for a laboratory instrument. This instrument will illustrate signals, which partake on generation QAM modulation. The design of the laboratory instrument includes theoretic schemata and the execution of a prototype. There are theoretical facts of multi-state signals and multi-state modulations in this thesis. A simple block diagram of the laboratory instrument is made by the theory of creating quadrature amplitude modulation. For each block there are made several schemata, which are compiled to the global scheme. A printed circuit board and the structure items are made by the aid of the global scheme. The next part is devoted to a software facility for a used microprocessor, which ensures the whole function of the laboratory instrument. The final section deals with measuring, which checks the function of the modulator and the right setting coder’s constellation diagrams.
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High-speed optical transmission systems
Pekárková, Kateřina ; Číž, Radim (referee) ; Münster, Petr (advisor)
The diploma thesis is focused on high-speed optical connections using optical fibers for transmission and transmission systems with speeds above 100\,Gb/s. In the first part of the work, the theory of the area of optical high-speed connections is discussed, especially the work is focused on the coherent type of data transmissions. Modulation and multiplexing formats, chromatic dispersion, modal and polarization modal dispersion, optical fiber attenuation and nonlinear phenomena are also described. The theoretical part of the work also deals with the description of the differences between coherent and non-coherent transmission methods and the description of coherent high-speed optical transmission and its components. The practical part contains two laboratory tasks that, using simulations in the VPIphotonics environment, compare two-state and multi-state modulation for systems with a transfer rate of 10\,Gbit/s and 100\,Gbit/s. The properties of these modulation formats are demonstrated using decision eye diagrams, constellation diagram and bit error rate values for different lengths of optical fiber, which are the output of the simulation environment.
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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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QAM Modulator
Duffek, Luděk ; Kubánek, David (referee) ; Číž, Radim (advisor)
The thesis focuses on consideration of possible ways how to realize multi-state modulators for a laboratory instrument. This instrument will illustrate signals, which partake on generation QAM modulation. The design of the laboratory instrument includes theoretic schemata and the execution of a prototype. There are theoretical facts of multi-state signals and multi-state modulations in this thesis. A simple block diagram of the laboratory instrument is made by the theory of creating quadrature amplitude modulation. For each block there are made several schemata, which are compiled to the global scheme. A printed circuit board and the structure items are made by the aid of the global scheme. The next part is devoted to a software facility for a used microprocessor, which ensures the whole function of the laboratory instrument. The final section deals with measuring, which checks the function of the modulator and the right setting coder’s constellation diagrams.
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