V. B. Avdeev, V. D. Mochalin

The differential method of transformation of spatial fluctuations of the optical beam arising from its reflection from vibrating objects, in an electric signal is proved. The mathematical model of the differential optic-electronic converter of correlation type for the light-sensitive elements of a photodetector, having rectangular and round forms, and the rectangular form of area of their illumination by an optical beam is developed. It is shown that involving the noise amplitude modulation of probing radiation such converter keeps the high sensitivity in the process of detection of object vibrations. The optimal geometrical dimensions of the converter, at which at the its output the «signal/noise» maximal ratio is achieved at the given amplitude of displacement of illumination area of a photodetector, caused by presence of a signal, are found.