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:
Mar. 28, 1989
Filed:
Apr. 07, 1988
Applicant:
Inventors:
Steven E Michalski, Franklin, WI (US);
Kevin M Andrews, Rockford, IL (US);
Daniel Mieczkowski, Kenosha, WI (US);
Assignee:
Snap-on Tools Corporation, Kenosha, WI (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G01R / ; G11C / ;
U.S. Cl.
CPC ...
324130 ; 307353 ; 328151 ; 330-9 ;
Abstract
A sensor is periodically energized and the sensor output is amplified, the amplified signal being applied to two sample-and-hold circuits which are alternately activated in response to the sensor drive, one being activated only when the sensor is energized and the other being activated when the sensor is not energized. One of the samples is subtracted from the other in a summer for cancelling the amplifier offset. The summer output may be buffered, and there is also applied to the summer an offset correction signal for cancelling sensor offset and buffer offset inaccuracies.