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Lasers based on the double-clad fibers fabricated in IREE AS CR
Zavadilová, A. ; Kubeček, V. ; Kašík, Ivan ; Matějec, Vlastimil
In this artical the fiber lasers using double-clad fibers as an active medium, fabricated in IREE AS CR are presented. This fibers are doped by erbium and ytterbium ions with different concentration ratio. These fibers have also different lateral structure like refractive index profile or material of secondary cladding. For these fibers the optimal lenght, maximum power and efficiency of linear resonator in configuration without external reflected components were found.
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Modelling of optical microresonators
Hubálek, Milan ; Čtyroký, Jiří
The contribution outlines modelling techniques for analysis of microresonator-based integrated optical components. A principle of modelling of the time domain characteristics with the help of the spectral characteristics including influence of nonlinear optic effects is carried out. Results applicable in the field all-optical devices are shown.
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Simulation of the enciphering algorithm RSA in MATLAB
Čížek, Václav ; Švandová, Hana
Enciphering algorithm RSA is up to now hold for one almost not decipherable methods of enciphering. At present it is used also for the electronic signature. The algorithm is based on elementary knowledge in number theory like congruence, Euler function and modular inversion. Because some number theoretic operations mey be processed in MATLAB it is shown, how the RSA algorithm can be simulated in MATLAB. Results and some simulation difficulties of the RSA algorithm are presented.
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Introduction to time and frequency metrology
Čermák, Jan
Basic concepts such as time interval, time scale and synchronization encountered in metrology of time and frequency are introduced. Attention is paid to frequency staility. Also described are the methods of accurate time transfer applicable in the territory of the Czech Republic /GPS, DCF long-wave transmission, internet/.
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Measurement of time and frequency
Čermák, Jan
Basic methods of time and frequency measurement are described. Attention is paid to measurement of period, frequency and time interval based on reciprocal time-interval counter. Stanford Research 620 counter serves to illustrate the case. Also mentioned is the calibration/measurement capability of the National Time and Frequency Standard.
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Zpracování řeči
Speech Processing is a periodic publication collecting the contributions presented at the Czech-German Workshops on Speech Processing organized every year in September in Prague. The papers are devoted to speech analysis, synthesis, recognition, enhancement and phonetics.
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