Národní úložiště šedé literatury Nalezeno 4 záznamů.  Hledání trvalo 0.01 vteřin. 
Laser head with VCSEL laser diode
Mikel, Břetislav ; Urban, F.
We describe a new laser head with Vertical Cavity Surface Emitting Laser (VCSEL) diode. The VCSEL lasers at 760 nm with mode-hop free tuning range above 1 nm are affordable now. The VCSEL's are fabricated as circulary-symetric lasers; the circular aperture is of particular value as it implies a circular beam profile. The linewidth and the optical noise of the VCSEL laser diode depend on the stability of the current source controller and on the quality temperature control system. We developed a digital temperature control system with temperature stability below 1 mK and high stability current source conttroller.
Digital Controlled Electronics for Three-dimension Hydrophone Position System
Václavík, V. ; Rozman, J. ; Číp, Ondřej ; Mikel, Břetislav
Set of geared DC motors is employed as mechanical actuator for three-dimensional positioning of the needle hydrophone probe in the ultrasound scannig tank. High-resolution position sensors inside DC motors and a digital signal processing used for digital PID servo-loop improves dynamic range and precision of the sensor position set up.
New method for direct measurement of refraction index of air with He-Ne lasers
Matoušek, Vít ; Číp, Ondřej
Interferometer methods are used for the high accuracy measurement of distance by specifying the measurement of the air index, since the measurement of the refraction index of air is in atmosphere, the refraction index of air is dependant upon temperature, pressure and humidity. For the measurement of the refraction index of air, Eden's formula is usually used. The formula depends upon the atmospheric values and the CO2 concentration.

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