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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Realistické zobrazování sněhu / Realistic Visualization of Snow

Chukir, Patrik January 2021 (has links)
This diploma thesis follows visualization of snow formations, which are called penitentes. This work includes also collecting the data needed to derive the optical properties of the penitentes material. Which are different phases between snow and ice. For visualization method is used Progressive Transient Photon Beams, that this work implements with the help of SmallUbpb.
22

Koherentní analogové zpracování optické informace / Coherent Analog Processing of Optical Information

Hrůza, Libor January 2008 (has links)
In my essay I show Fourier transform theory and applications in context with difraction theory especially Fraunhofer difraction. In part of the experiment, I set up an optical signal processing system. I take the Fourier transform of an input signal using a lens, filter the transform by placing various filters at the Fourier plane, and take the inverse transform. A simple optical bench consists of a laser, to produce a parallel, monochromatic beam which illuminates a specific area of the micrograph. Lens to focus the Fraunhofer diffraction pattern in the back focal plane of the lens. Mask transit contrived light or block out most of the noise in the diffraction pattern arising from image features. A reconstruction lens, placed behind the mask, refocuses the unobstructed rays and forms a filtered image. Optical diffraction provides useful information about the geometrical arrangement of subunits in the specimen. I make experiments for attestation on elementary objects and real images in mathematic program Matlab. From knowledge Fraunhofer difraction and organization of experiment I calculated size of circular object. I show practical using of Fraunhofer difraction and optical filtration. My essay give good introduction to the theory and techniques of optical filtration.
23

Laserový vysílač s optickým vláknem / Laser transmitter with fiber

Hašek, Jaroslav January 2009 (has links)
This master´s thesis deals with communication which is provided by optical devices. Optical wireless links are enforced due to high bit rate, responsibility and noise immunity. Main part of this master´s project is devoted to optical fibre, its characteristic and its usage in laser transmitter.
24

Generování testovacích vzorů / Test pattern generation

Hašek, Martin January 2010 (has links)
This thesis is focused on application development for simulation lenses’ optical distortions and also for creation own patterns. In the first part are discussed common problems of optical distortion and concept of software analysis. Further is described realization and implementation of particular modules in the application. In the end is show up graphical user interface and its functionality.
25

PMD - polarizační vlivy optických vláken / Optical fibres and their polarization effect

Klesnil, Ondřej January 2010 (has links)
This project describes the fundamental concepts and basic theory of polarization mode dispersion (PMD) in optical fibers. There are described basic the relation between Jones vectors and Stokes vectors, rotation matrices, the definition and representation of PMD vectors, the laws of infinitesimal rotation. After the introduction the first conception with bases of polarization mode dispersion (PMD) in optical fibers, they have become an important body of knowledge basic for the design of high-capacity optical communication systems. PMD effects are linear electromagnetic propagation phenomena occurring in so-called “single-mode“fibers. Despite their name, these fibers support two modes of propagation distinguished by their polarization. Because of optical birefringence in the fiber, the two modes travel with different group velocities, and the random change of this birefringence along the fiber length results in random coupling between the modes. With current practical transmission technology the resulting PMD phenomena lead to pulse distortion and system impairments that limit the transmission capacity of the fiber. I describe different ways of measuring PMD in optical fibre, PMD compensation techniques and analyse PMD results in optical fibres.
26

Modelování vícekanálového optického bezkabelového spoje / Modeling of the multichannel optical wireless link

Pavlů, Michal January 2012 (has links)
This thesis deals with multi-channel wireless links with a higher range designated for free-space communications in an atmospheric media. Propagation of the optical beam in an atmosphere is analysed and various influences affecting the quality of the transmitted signal are described. The simulation is carried out for dual optical link. Link budget of individual paths working at the wavelengths in the atmospheric windows – 850 nm and 1550nm. It also examined optical intensity distribution of the transmitted beam. At the end of the work performed measurements and simulations verify the accuracy of the components used in wireless link.
27

Možnosti zvýšení propustnosti optovláknové průmyslové sítě / Possibilities of increasing the throughput of optical fiber industrial networks

Čičmanský, Tomáš January 2015 (has links)
Diploma thesis deals with problems of industrial networks using optical fiber as the main transmission lines. The task of the diploma work is to study and summarize the issues of industrial networks as well as the ways to increase their transmission capacity. In telecommunications and computer networks are generally used multiplexes, thanks to which we are able to achieve the desired transmission capacity. Consequently, the following work deals with the selection of the adequate solutions using described multiplexes as well as other transmission methods. The aim of the diploma work is to compare various renovation techniques of an old industrial network. Using this network as an example the work should demonstrate the individual problems and their solutions while considering different types of methods used. Based on the price, the performance and the difficulty to install other devices and transmission media we are able to select the appropriate solution for optical link.
28

Využití optických zesilovačů v sítích NG-PON2 / Using Optical Amplifiers in NG-PON2 Networks

Hrmel, Martin January 2014 (has links)
The aim of the thesis was to introduce the standard ITU-T G.989. Introduction deals with passive network architecture, which clarifies the basic functional elements that occur in optical networks. Been described active components and the very principle of data transfer in the distribution network. Next section is devoted to new technologies that are defined for the latest generation of passive networks NG-PON2. There have been a principle of data transmission in such networks and their advantages and disadvantages. I described the principle of data transmission in such networks and their advantages and disadvantages. The practical part deals with creating a functional network of NG-PON2 also using optical amplifiers. Another suggestion was using a digital CATV transmission of QAM modulation under optical networks on a dedicated wavelength of 1550 nm. Also simulate the coexistence of this new standard with previous PON technologies. Finally, the work consisted in implementing the Miller’s code into OptSim v5.2 environment, which compared the transmission characteristics of each line of codes with this Miller’s code. All practical simulations were designed and simulated in program OptSim v5.2.
29

Měření mechanické stability budov a stožárů využívaných pro FSO spoje / Measurement of the Mechanical Stability of Buildings and Consoles Used for the FSO Links

Kočvara, Pavel January 2015 (has links)
The Master's thesis deals with the determination of measurement method of deflection the axis of the optical beam from its ideal position, which is caused by action of force of strong winds affecting the positional stability of the building or supporting structure (tower) used for placement of FSO links'heads. The thesis informs the readers about the other causes of deflection of beam axis in a real environment, about methods of determining the position of the beam axis in the plane perpendicular to the beam axis and the basic properties and parameters of the Gauss beams, including the phenomenon of diffraction on the output aperture of the laser transmitter.
30

Přesnost měření na dílenských mikroskopech / Accuracy of measurement on workshop microscope

Pernikář, Václav January 2008 (has links)
This thesis deals with the performance of the measurement accuracy in the optical measuring systems. The first part describes basic principles of metrology and the guidelines of the expression of uncertainty and the factors which influence measurement result. The second part classifies optical measuring systems and describes some measuring principles of them. The final part compares two optical gauges and the evaluation of some of their characteristics through the use of very simple experiments.

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