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:
Aug. 21, 2001
Filed:
Mar. 09, 1998
Vijendra Kuroodi, Cupertino, CA (US);
Tritech Microelectronics, Inc., Milpitas, CA (US);
Abstract
This invention describes a method and apparatus for filtering noise from a measurement of the X and Y coordinates of a resistive digitizer. The method applies to both four and five wire resistive digitizers biased with a DC voltage. The same filtering and measurement apparatus can be used on both types of digitizers with inclusion of an extra signal pin to accommodate the sense lead of the five wire digitizer. This approach involves connecting the signal to be read to a filter, reading the filtered voltage, and disconnecting the signal from the filter before disconnecting bias voltage from the planes of the digitizer. A separate filter is used for the X and Y coordinate signals and each filter voltage can be read at any time before the next measurement. A reset voltage is available to an established reference on the filter capacitor when a “pen up” status is detected.