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Antenna system for wireless microphones
Bartoš, Adam ; Lukeš, Zbyněk (referee) ; Láčík, Jaroslav (advisor)
Master's thesis deals with the design of an antenna system for wireless sound transmission used mainly in professional sound reinforcement. The introductory part deals generally with wireless microphones, frequency bands used and proven antenna types. Next, this work deals with signal distribution that is realized using the antenna splitter. The antenna parts is focused on easy production and real usage, therefore were selected antennas with appropriate properties suitable for small series production. This thesis includes simulation of each device, their real construction design and measurements of built prototypes and final products. All three produced devices – the rack splitter, /4 antenna and Helix antenna are fully working, achieve good parameters and are ready for further manufacturing and easy modifications in case of frequency band change requirement. The conclusion includes an overall assessment of the results achieved.
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Cellular Network Coverage Model
Unzeitig, Lubomír ; Mikulka, Jan (referee) ; Gleissner, Filip (advisor)
This work deals with a mobile signal propagation in electromagnetic wave form in a real environment of city microcell. The electromagnetic wave passing through the city environment is affected by many kinds of mechanism. It includes especially diffraction along vertical edges of buildings, diffraction across building roofs and buildings or ground refraction. These mechanisms are time variable. If we want to predicate them, we have to use sort of approached model. For an experimental part of this work, the Berg’s recursive model with a possibility of path loses or signal level prediction in a selected microcellular system is chosen. The software for a cellular network coverage is created on the basis of this fact. Its advantage is a possibility of up to five base stations placing and many kinds of settings, e.g. operating frequency, base station transmitting power, base and mobile station antennas height etc. There is a possibility of system GSM 900, GSM 1800 or UMTS choice. The Berg’s recursive model features are checked by simulations on experimental and real maps of build-up area.
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Power amplifier for 435MHz Band with High Efficiency
Herceg, Erik ; Špaček, Jiří (referee) ; Urbanec, Tomáš (advisor)
This diploma thesis is focused on design of high frequency power amplifiers in UHF band, specifically at 435 MHz. Amplifiers are designed in different classes of operation. The thesis deals with the comparison of main parameters in each class of operation, the most important parameter is effeciency. The amplifying part is unipolar transistor which is working in Single-stage mode. The results were simulated in Advanced Design Systems Software.
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Design Of The Pulse Generator For Testing And Validating Partial Discharge Measuring Systems
Hejtmánek, Tomáš
This article deals with the design and implementation of a pulse generator serving as acalibration generator for setting up measuring systems for monitoring the activity of partial discharges(PD) in the high-voltage power transformers or gas insulated switchgears (GIS). After installingthe measuring device, it is advisable to test the entire measuring chain and, if necessary, setparameters that would affect the correct detection of PD signals. Calibration pulse generators areused for setting and validating measuring chain. These are usually used in systems that sense theelectromagnetic activity of PD. Correct and timely detection of PD can avert a transformer accidentand thus contribute to higher safety in power plants. The proposed generator should serve as theoutput part of a programmable generator, which did not reach sufficient parameters of output pulses.The goal was to achieve a rising time around 100 ps and an amplitude of more than 6 V usingmodern and very fast operational amplifiers and step recovery diodes as a sharpener of the inputpulse. The measurements show waveform of the output voltage pulse.
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Coexistence Between Dvb-T2 And Lte Systems In The 800 Mhz Band – A Measurement Methodology
Walach, Dominik
This article deals with the study of coexistence between DVB-T2 and LTE systems. Coexistence scenario between DVB-T2 and LTE systems in the 800 MHz UHF band is defined. Next, a laboratory workplace is realized, and a measurement methodology is proposed. Its functionality is verified by experimental measurements. The proposed concept also facilitates to test sensitivity of DVB-T2 receivers (set-top-boxes) against interfering LTE signals.
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Antenna system for wireless microphones
Bartoš, Adam ; Lukeš, Zbyněk (referee) ; Láčík, Jaroslav (advisor)
Master's thesis deals with the design of an antenna system for wireless sound transmission used mainly in professional sound reinforcement. The introductory part deals generally with wireless microphones, frequency bands used and proven antenna types. Next, this work deals with signal distribution that is realized using the antenna splitter. The antenna parts is focused on easy production and real usage, therefore were selected antennas with appropriate properties suitable for small series production. This thesis includes simulation of each device, their real construction design and measurements of built prototypes and final products. All three produced devices – the rack splitter, /4 antenna and Helix antenna are fully working, achieve good parameters and are ready for further manufacturing and easy modifications in case of frequency band change requirement. The conclusion includes an overall assessment of the results achieved.
|
|
|
Power amplifier for 435MHz Band with High Efficiency
Herceg, Erik ; Špaček, Jiří (referee) ; Urbanec, Tomáš (advisor)
This diploma thesis is focused on design of high frequency power amplifiers in UHF band, specifically at 435 MHz. Amplifiers are designed in different classes of operation. The thesis deals with the comparison of main parameters in each class of operation, the most important parameter is effeciency. The amplifying part is unipolar transistor which is working in Single-stage mode. The results were simulated in Advanced Design Systems Software.
|
|
|
Cellular Network Coverage Model
Unzeitig, Lubomír ; Mikulka, Jan (referee) ; Gleissner, Filip (advisor)
This work deals with a mobile signal propagation in electromagnetic wave form in a real environment of city microcell. The electromagnetic wave passing through the city environment is affected by many kinds of mechanism. It includes especially diffraction along vertical edges of buildings, diffraction across building roofs and buildings or ground refraction. These mechanisms are time variable. If we want to predicate them, we have to use sort of approached model. For an experimental part of this work, the Berg’s recursive model with a possibility of path loses or signal level prediction in a selected microcellular system is chosen. The software for a cellular network coverage is created on the basis of this fact. Its advantage is a possibility of up to five base stations placing and many kinds of settings, e.g. operating frequency, base station transmitting power, base and mobile station antennas height etc. There is a possibility of system GSM 900, GSM 1800 or UMTS choice. The Berg’s recursive model features are checked by simulations on experimental and real maps of build-up area.
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