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Free-Space Optics data link
Šála, Jakub ; Číž, Radim (referee) ; Šporik, Jan (advisor)
In this thesis, shows a current issue for free space optics, limiting their use in practice with regard to the availability and reliability. They conducted measurements on wireless optical links and the observed values is calculated by the availability of the connection. Subsequently, measurements are performed on alternate versions of wireless and copper connections. Observed values were compared with a wireless optical link. It is made of optical design of wireless connections at home.
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BIT ERROR RATE AND AVAILABILITY OF THE ATMOSPHERIC OPTICAL LINKS
Kvíčala, Radek ; Vašinek, Vladimír (referee) ; Fišer, Ondřej (referee) ; Wilfert, Otakar (advisor)
This dissertation deals with the problematic of the free space optical link availability determination. For the presumption of the free space optical link unavailability we have to know statistical distribution of the atmospheric attenuations. In this work is also presented the measurement of these atmospheric attenuations with the specially designed optical link. Measurement is using switching of the two separate transmitters with wavelengths of 830 nm and 1550 nm. Presented statistic distribution let us determine the suitability of the link in the chosen locality during its design. Comparison of our measurement with other models like model based on the meteorological visibility is also presented. The last part of this work is focused on the preconditions for the hi-speed network bit error rate determination. Sample of the bit error rate measurement obtained by our designed bit error rate tester is attached.
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Optical communication in ultra violet band
Golubev, Martin ; Hudcová, Lucie (referee) ; Poliak, Juraj (advisor)
This bachelor thesis deals with analyzing atmospheric transmission media properties and performance ratio in ultraviolet band optics beam propagating in Earth's atmosphere. In work are definited a optical phenomenons, their implications and use. Description of atmospheric transmission media analyzes the impact of individual particles in the atmosphere on optical beams. There are described a effect of ultraviolet light on living organisms. Simulations of performance ratio using Matlab and proposal of concrete link of UV NLOS for short range are serve as a basis for further research into this field of optical communications.
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Wireless connections for metropolitan networks
Svoboda, Jan ; Tejkal, Vladimír (referee) ; Šporik, Jan (advisor)
This Master’s thesis analizes technologies suitable for metropolitan area networks. In this thesis there are mentioned technologies used for wireless transfer with speeds above 1 Gbps. There are described basic features and parameters of microwave radio relay links in 70/80GHz range and free space optic links. These technologies are compared with classic optical networks. Practical part of thesis was focused on development of application which calculates signal attenuation caused by the passage of the atmosphere for both technologies. Results gained from this application are mentioned in this Master’s thesis.
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Method of Atmospheric Transmission Media Characteristics Determination in Optical Spectrum
Hudcová, Lucie ; Lazar, Josef (referee) ; Vlček, Čestmír (referee) ; Wilfert, Otakar (advisor)
This dissertation is focused on the determination of turbulent atmospheric transmission media properties. The concept of new method for turbulent attenuation designation is presented – the method of available power. This method comes from laser beam intensity profile analysis. The next point of this work is relative variance of optical intensity study. On the basis of experimental measurements relative variance of optical intensity is non-uniformly distributed in laser beam intensity profile. This non uniform distribution is subordinated to angular coefficient of intensity profile curve. Due to this information we can determine optimal laser beam shape to minimize influence of turbulent atmosphere.
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Influence of atmospheric turbulences on the optical beam
Bárta, Miroslav ; Wilfert, Otakar (referee) ; Hudcová, Lucie (advisor)
The aim of this thesis is to study a free space optics and its application in communication technologies. It describes possible interrupting impacts on the beamed optical signal, which are signal noise, attenuation of the atmosphere and atmospheric turbulence. The basis of the thesis is to describe the impact of the atmospheric turbulences on the optical beam. Fluctuation of optical intensity in the optical beam has been measured and index of refraction structure parameter calculated. With its assistance, turbulence rate has been determined.
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Wireless optical links in LAN and MAN networks
Šporik, Jan ; Dostál, Otto (referee) ; Filka, Miloslav (advisor)
The main aim of this thesis is the design of an optical wireless link that is transmitted in free space, in the atmosphere. The thesis describes the composition of heads of the atmospheric optical link. One part of this work focuses on the issue of the spread of optical beam in the atmosphere. The facts which have a major impact on the transmission of optical radiation in free space are pointed out here as well. In this work phenomena of absorption, refraction of light, turbulence and dispersion are discussed. Wavelengths spread in the atmosphere with different decline and therefore this thesis provides an analysis of the use of wavelengths between 750 and 1600 nm depending on the meteorological visibility. It describes the basis of the design of AOS through stationary model using power balance equation. It depicts the description of the statistical model, which makes possible to determine the availability on the basis of probability. Current possibilities of AOS are in general described in this work. The practical part of the work is focused on the design of simulation model of transmitter and receiver AOS in the program Pspice. The receiver and transmitter are designed to replace transiver in the media converter. The receiver plays a key role, and therefore big part of the thesis is given to it. Receiver model is composed of a photodiode and of an transimpedance amplifier. The receiver circuit has been tested. The model of transmitter shows the principle of modulating of current, which flows in laser diode. This work does not carried the model of atmosphere, which would serve as a link between the receiver and the transmitter. The circuit of the receiver is subjected to the noise analysis. Parameter NEP and SNR is designed. Link budget is calculated for models of the receivers and the transmitters. The maximum distance of heads is set based on the requirements for a BER error rate which combine this condition. The design of the practical implementation results from the models of transmitters and receivers. Printed circuit boards are designed in EAGLE. Within the frame of this thesis no curcuit diagram is carried out.
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RONJA TWISTER Based on FPGA
Matyáš, Jan ; Kaštil, Jan (referee) ; Vašíček, Zdeněk (advisor)
RONJA is an open-source hardware project for an optical data-link device which utilizes a visible-light beam for wireless data transmission. This thesis focuses on a single electronic module called RONJA Twister, which forms an interface between metallic Ethernet and the optical transmission itself. The purpose of this project is to reimplement the original Twister module design in a backward-compatible manner using FPGA technology. Furthermore, the proposed and implemented solution enhances the module by incorporating the Auto-Negotiation capability which mitigates several issues of the original Twister module.
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The System For Laser Beam Tracking And Communication
Skryja, Petr
The paper describes a system for laser beam tracking and communication with using one optical laser beam. As an active receiver element, improved tetra-lateral two-dimensional position sensitive detector S5991-01 is used, which is used both to obtain beam position and to receive transmitted data. A laser with a wavelength of 650 nm is used for data transmission. The transmitted data are coded with Manchester code. Position calculation, data receiving and transmitting is carried out by development board STM Nucleo H743ZI.
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Network Interface for Microblaze
Janík, Lukáš
This article deals with interfacing of Xilinx MicroBlaze (UB) softcore microprocessor to 1 Gb/s Ethernet data bus via custom simple Ethernet switch. This interface is implemented on an FPGA board and serves as the lower communication layer for administration of gigabit Ethernet-tooptical bridge.
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