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. 03, 2002
Filed:
Aug. 03, 2001
Michael Nahum, Kirkland, WA (US);
Patrick H. Mawet, Snohomish, WA (US);
Mitutoyo Corporation, Kanagawa-ken, JP;
Abstract
A system and method for determination of error parameters for performing self-calibration and other functions in a transducer. The method utilizes the minimum and maximum values of the output signals of the transducer. To obtain these values, the output signals are measured at various times according to the sample timing, as the read head is scanned relative to the scale. The offset for each phase is determined to be equal to the average between the maximum and minimum voltages. The signal amplitudes are equal to the difference between the maximum and the minimum voltages, divided by two. By comparing the amplitude for each phase, the amplitude mismatch is found. The phase relation error may be determined by first removing the amplitude mismatch and the offset errors from each phase, and then comparing the relative amplitudes of the two signals at a given point in relation to what they ought to be with no phase relation error. The described method provides a fast calibration method which requires a minimum amount of data, and which can be automatically run in a background mode without inhibiting normal transducer operation.