The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 19, 1989
Filed:
Dec. 10, 1987
Applicant:
Inventors:
John P Dakin, Hampshire, GB;
David J Pratt, Suffolk, GB;
Assignee:
Plessey Overseas Limited, Ilford, GB;
Primary Examiner:
Int. Cl.
CPC ...
G01J / ;
U.S. Cl.
CPC ...
250226 ; 250227 ;
Abstract
A two-wavelength referencing optical sensing arrangement comprises two laser sources for producing simultaneous optical pulse signals of two different wavelengths for transmission over a plurality of discrete optical fibre paths to the sensors terminating such paths. Time-displaced return signals of different wavelengths received over the optical paths from sensors are fed into a single receiver which uses the intensity of signals of one wavelength in order to compensate for unknown losses in the system when indicating measurement of conditions sensed at the locations of the optical sensors.