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Methods for quadrature modulator imbalance compensation
Povalač, Karel ; Valenta, Václav (referee) ; Maršálek, Roman (advisor)
Quadrature modulator (demodulator) is used in transmitting (receiving) part of many devices. Unwanted imbalance can influence amplitude, phase or DC offset of modulator (demodulator). Correction of imbalance was a main subject of thesis. Simulations of these methods were created in MATLAB and results were compared. Basics of methods were implement on programmable logic field by program Xilinx ISE. Development kit V2MB1000 with analogue board Memec P160 was chosen for this purpose. In the last part were compare simulation results with practical measurement.
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Digital predistorters for amplifier linearization
Kroužil, Miroslav ; Valenta, Václav (referee) ; Maršálek, Roman (advisor)
In this work I describe digital predistortion in baseband used for amplifier linearization. Non-linearity is one of the worst disadvantages of Power amplifiers and decreasing of its is useful from many reasons. Work examines system which contains: Data source, which is represented by QPSK or OFDM modulator, predistorter, Power amplifier (model of non-linearity) and unit used to update coeficients for predistorter adaptation. System is simulated in MATLAB and Xilinx (simulation by ModelSim). Results are compared, described and commented.
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Adaptive OFDM
Nowak, Dan ; Valenta, Václav (referee) ; Maršálek, Roman (advisor)
The purpose of this paper is to study the possibilities of the OFDM system adaptive modulation. The study presents mechanism for acquiring the necessary data of every frequency subchannel using pilot signals and application of these data for system adjustment. The paper introduces the water-filling principle for subchannel power allocation on the basis of their SNR and adaptive modulation mechanisms for variety of OFDM usage. These mechanisms are implemented into a MATLAB model. The code is then transformed into graphical representation and using USRP2, the signal is transmitted by real world channel.
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Synchronization methods for millimeter-wave 5G systems
Waldecker, Miroslav ; Valenta, Václav (referee) ; Maršálek, Roman (advisor)
Goal of this thesis is to analyse basic algorithms for the carrier and time synchronisation in the OFDM systems in 5G networks. Firtly, basic introduction to OFDM systems, then parameters and properties of the OFDM are discussed. Then estimation and compensation timing and frequency offsets are analysed as well as algorythms for searhcing of the start of the symbols. Last but not least hardware setup, which will be prepared in the DREL department for test of the communication in the millimeter wave band, with frequency of 60GHz is slightly discribed. This thesis is just a introduction for the real future work on this setup.
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Synchronization methods for millimeter-wave 5G systems
Waldecker, Miroslav ; Valenta, Václav (referee) ; Maršálek, Roman (advisor)
Goal of this thesis is to analyse basic algorithms for the carrier and time synchronisation in the OFDM systems in 5G networks. Firtly, basic introduction to OFDM systems, then parameters and properties of the OFDM are discussed. Then estimation and compensation timing and frequency offsets are analysed as well as algorythms for searhcing of the start of the symbols. Last but not least hardware setup, which will be prepared in the DREL department for test of the communication in the millimeter wave band, with frequency of 60GHz is slightly discribed. This thesis is just a introduction for the real future work on this setup.
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Taylor Series Assembler
Valenta, Václav ; Kraus, Michal (referee) ; Kunovský, Jiří (advisor)
The objective of this work is to get familiar with numerical solution of differential equations. The solution is made by specialized microprocessor HC08. Basic arithmetic operations and algorithms which helps to make precise results are analyzed here.
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