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:
Apr. 11, 1995
Filed:
Dec. 22, 1992
Applicant:
Inventor:
Stephen J Curtis, Nashua, NH (US);
Assignee:
Other;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G08B / ;
U.S. Cl.
CPC ...
340653 ; 340657 ; 340658 ; 250205 ;
Abstract
A system is disclosed for monitoring the operation of an encoder having a scale which is illuminated from a light source, in which light from the scale is detected by a detector, with the encoder having means coupled to the detector for detecting in-phase and quadrature signals representing scale position, means for detecting the phase difference between the in-phase and quadrature signals, and means responsive to the detected phase difference for adjusting the output of the light source to maintain its output at a predetermined level and for providing an error signal representing the amount of adjustment of the output of the light source.