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Implementation Of Fsk Modulated Signal Receiver Using Software Defined Radio
Pospisil, Jan
This paper discusses recent trends in a wireless communication system using Software DefinedRadio (SDR). SDR, in this case, the BladeRF 2.0, in combination with a software layer writtenin the Python language, is taking care of signal demodulation. BladeRF 2.0 is a device that providesa powerful waveform development platform expected by industry professionals. The BladeRF 2.0 isused to design a Frequency Shift Keying (FSK) receiver (in the form of binary data). As a transmitter,we created a custom-designed end-device using CC1101 RF (Radio Frequency) module. The scenarioin the current experiment is that the SDR acts as a receiver for the transmitting end-node.
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Comparison Of Promising Tdoa Geolocation Algorithms For Low-Power Wide-Area Network
Pospíšil, Jan
The paper deals with the comparison of promising end-device geolocation algorithms in a multipath propagation environment using the Time-Difference of Arrival (TDoA) information, that is incoming signal propagation delays from the end-device to the gateways. Comparison by simulation with added noise to outline the real conditions for a variety of selected computational algorithms. Namely comparison of the sensitivity of the algorithms to noise, the influence of the gateway count on the positioning error and calculation time requirements have been done.
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Perovskite single crystals for the detection of electromagnetic radiation
Gavranović, Stevan ; Novák, Vítězslav (referee) ; Pospíšil, Jan (advisor)
This thesis is focused on the study of the detection of electromagnetic radiation using monocrystalline perovskites. Theoretical part deals with basic principles of detections and possible applications of hybrid perovskite crystals in the field of ultraviolet and visible spectrum detection. Parameters of the recently published perovskite photodetectors are also presented. Experimental part describes synthesis, structural and optical properties of MAPbBr3 single crystals and electrical characterization of the Au/MAPbBr3/Au photodetector. Photodetector parameters (responsivity, external quantum efficiency and specific detectivity) are calculated based on the spectral and switching (on/off) current responses.
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Study of the dielectric properties of perovskite crystals
Mlčkovová, Hana ; Pospíšil, Jan (referee) ; Zmeškal, Oldřich (advisor)
The presented diploma thesis deals with the preparation of perovskite single crystals by inverse thermal crystallization and subsequent study of the basic properties of these hybrid organic-inorganic materials that can be used in various optoelectronic (photodetectors, transistors, lasers, LEDs) or photovoltaic applications. Their behavior in the electric field was studied by impedance spectroscopy. Impedance and capacitance-voltage (C-V) characteristics (frequency dependences) were measured in the dark and in the light. From the impedance dependences for measurements at 0 V voltage in the dark, the equivalent circuit was modeled and its parameters and dielectric constant were determined. From the C-V dependence, Mott-Schottky analysis determined the parameters – "flat-band" potential U_"fb" and charge carrier density N_"C-V" , the parameter – the so-called Warburg coefficient was found, which together with the parameter N_"C-V" was used to calculate the diffusion coefficient D.
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Passivation of the active layer in perovskite solar cells with inverted architecture
Babincová, Kristina ; Zmeškal, Oldřich (referee) ; Pospíšil, Jan (advisor)
The topic of this work is the passivation of the active layer of perovskite solar cells with an inverted structure. The work is divided into theoretical and experimental part. The theoretical part describes in particular the passivation and modification of the perovskite layer as well as the characteristic properties of perovskite, including structure and stability. The experimental part deals with the preparation of photovoltaic cells with an inverted structure. For the characterization of photovoltaic cells, reference samples were prepared and their active layer was modified by plasma. The most used deposition technique for the preparation of layers was the spin coating method. From the performed experiments it can be concluded that the preparation of samples and their subsequent modification under laboratory conditions does not lead to the improvement of the final parameters of photovoltaic conversion. By transferring the sample preparation and passivation of the active layer to an inert atmosphere, it was possible to produce cells with higher efficiencies (compared to the reference sample), around 10 %. Another advantage of this plasma treatment of the active layer is that it also improves the stability of the prepared structures, which even after a few days in air show almost 80 % of the original efficiency.
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Preparation of perovskite solar cells with regular n-i-p architecture and their optimization
Poláková, Simona ; Zmeškal, Oldřich (referee) ; Pospíšil, Jan (advisor)
The diploma thesis deals with the study of perovskite solar cells with a regular n-i-p architecture. The theoretical part of this work is mainly focused on the stability of perovskite solar cells, i.e. thermal stability and the influence of UV radiation on final perovskite solar cell stability. Furthermore, the deposition methods, the architecture of solar cells and the materials used for the preparation of electron and hole transport layers were described in more detail. The experimental part deals with the optimization of the preparation of perovskite solar cells (especially in terms of resulting photovoltaic conversion efficiency), with a description of the structure preparation process of the final photovoltaic cell and the interpretation of the measured results.
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Lighthouse for maritime communication
Chadima, Jan ; Mašek, Pavel (referee) ; Pospíšil, Jan (advisor)
This bachelor thesis deals with design and construction of lighthouse model, which will be used for teachning. It describes types of naval signalizacion, which are established by organization IALE in decree E-110. In thesis is described Arduino platform, metods of 3D printing and used materials For model needs was designed printed circuit board with microcontroller ATmega328P, which control RGB LED. Program, which control model, was writed on Arduino platform. Program has nine modes of sea light comunication. It can change periode, color of LED, brightness and turning on power saving mode. The result of this work is a functional model of lighthouse powerd by battery. Model is based on Green Cape Lighthouse in Australia in scale 1:58.
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Practical Demonstrator for Maritime Navigation
Michálek, Aleš ; Pospíšil, Jan (referee) ; Mašek, Pavel (advisor)
This bachelor thesis deals with the issue of naval buoys and their types. The theoretical part is about the history, physical construction of buoys, different types of colors, and the rhythm of lights. In the second, practical part is described the process of creating a 3D model of a buoy, miniaturized HW for electrifying the buoy model, and programming the code for a given microcontroller. In the end, the possibility of further expansion options is outlined.
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Passive capturing probe for IEEE 802.11 standard
Partnov, Denys ; Pospíšil, Ondřej (referee) ; Pospíšil, Jan (advisor)
The bachelor’s thesis deals with a general description of the 802.11 protocol, where the individual layers on which the protocol works are explained and described. Attention was also focused on the possibilities of securing wireless traffic. The practical part then deals with the creation of a complete tool for passive interception of traffic in IEEE 802.11 networks. Where it is mainly about processing traffic statistics. The resulting program, written in Python, allows the user to display current information such as: number of transmitted frames, channel, band, received signal strength, and more. Subsequently, the results can be displayed in the form of graphs. As part of the test measurement, the correct functionality of the program was verified.
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Virtualized web application for receiving data from sensors
Kharytonov, Oleh ; Fujdiak, Radek (referee) ; Pospíšil, Jan (advisor)
At the beginning of the theoretical part, the bachelor thesis focuses on LPWAN or Low-Power Wide-Area Network technology. Systems that are characterized by low power consumption and wide coverage. Their key features are discussed. Subsequently, attention is paid to the LoRaWAN\texttrademark\ standard,. Initially, LoRa\textsuperscript{\tiny\textregistered} modulation is discussed - the modulation techniques used and the advantages over competitors. The next step discusses LoRaWAN\texttrademark\, - architecture, types of end devices and security. Virtualization - uses in today's world, discusses types of virtualization and its benefits. The practical part introduces the commissioning of open-source LoRaWAN\texttrademark\, ChirpStack server, gateway, endpoint registration and activation. Attention is paid to an application programmed using Flask for device management and data reception. The principle of operation and commissioning of the virtualized web application is explained. Finally, the results and possible ways to improve the application are described.
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