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:
Jul. 31, 2007
Filed:
May. 13, 2003
James Mcinnes, Winchester, GB;
Maxwell R. Hadley, Lyndhurst, GB;
Arthur H. Hartog, Southampton, GB;
Yuehua Chen, Reading, GB;
Timothy Jeffreys, Winchester, GB;
James Mcinnes, Winchester, GB;
Maxwell R. Hadley, Lyndhurst, GB;
Arthur H. Hartog, Southampton, GB;
Yuehua Chen, Reading, GB;
Timothy Jeffreys, Winchester, GB;
Schlumberger Technology Corporation, Sugar Land, TX (US);
Abstract
An apparatus for sensing data from a remote optical sensorhas its frequency stabilised by balancing the outputs of narrow band filter, spaced about a desired frequencypositioned at about the 3 db down pointsof a broad band light sourceusing voltage control, current control or temperature control to vary the frequency of the wide band light source. Difference between the outputs through the two narrow band filterscan be used to drive an amplifierto correct the frequency of the broad band light source. The outputs through the two narrow band filterscan be convertedto binary numbers and fed to a microprocessorwhich is used, via analog conversion, to drive the amplifier. The broad band light sourcecan be pulse modulatedto provide temporally separate light pulsesthrough each of the narrow band filtersmeasured at separate times. The corrective output to the amplifiercan be governed by a ratio between the outputs through the narrow band filtersrather than by a difference there between.