1 Absolute frequency measurement of Mid Infrared secondary frequency standard at BNM-LPTF G. D. Rovera, , Member, IEEE and O. Acef Abstract|An absolute frequency measurement of a CO2=OsO4 secondary frequency standard, operating in the mid infrared, is reported. A brief description of the measurement chain linking this standard to a hydrogen maser evidences the critical points. The measured freq...

In this paper altitude measurement from water surface using laser beam is presented. Research data indicate that the reflection of infrared waves from water surface is about zero and it is less than 2% for visible radiations. Phase-shift and heterodyne technique was used for the measurement, and the laser beam ( mW p nm 10 , 700 = = l ) was modulated by a sine wave having a fixed frequency....

Grating displacement measurement technique is an important means to achieve precise displacement measurement of nanometer scale. Moiré fringe phase difference measurement is the basis of grating displacement measurement technique. Traditional Moiré fringe subdivision method based on DFT algorithm has low frequency resolution relatively when extracting Moiré fringe fundamental frequency spectral...