Accession Number : ADD004215

Title :   Phase Detector for Optical Figure Sensing.

Descriptive Note : Patent,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON D C

Personal Author(s) : Gowrinathan,Sankaran

Report Date : 21 Jun 1977

Pagination or Media Count : 6

Abstract : Phase detection between interfering light beams in an interferometric system is accomplished by frequency shifting the reference beam prior to combination with the interrogation beam and electro-optically scanning the resulting pattern to produce an FM electrical signal having the shift frequency as a carrier and the interrogated parameter as the modulation data. A phase lock loop is responsive to the FM signal to provide a D.C. signal that is analogous of rate of change of the interrogated parameter with scan, and which is integrated to provide an output voltage signal that is proportional to the interrogated parameter and the corresponding optical phase difference. The method and system employing it are operative for a wide range of phase differences including multiple fringes. (Author)

Descriptors :   *Patents, *Phase detectors, *Optical detectors, Interferometry, Phase shift, Beams(Electromagnetic), Frequency shift, Phase locked systems

Subject Categories : Optical Detection and Detectors
      Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE