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. 13, 2005
Filed:
Aug. 02, 2002
Frank C. Demarest, Higganum, CT (US);
Frank C. Demarest, Higganum, CT (US);
Zygo Corporation, Middlefield, CT (US);
Abstract
A method and apparatus used to reduce glitches in measurements made by an accumulation of phase changes over a range greater than 2π. Embodiments of the invention feature the use of a glitch filter that receives a phase input indicating a position value. The glitch filter reduces glitches by using a feedback term that has been reduced modulo 2π. The method includes measuring a plurality of values of a measurement signal, determining a current position value based on each of the plurality of measured values, wherein determining includes determining a delta value based on a current measured value and a previous position value, wherein the delta value is reduced modulo 2π to a range of ±π, and determining the current position value based on the determined delta value, and outputting at least one of the determined current position value and a velocity value.