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:
Sep. 17, 1996
Filed:
Jan. 05, 1994
Mark T Hanson, Lynnwood, WA (US);
Glade B Bacon, Everett, WA (US);
Microsoft Corporation, Redmond, WA (US);
Abstract
A method of detecting quadrature signals in a computer input device allows a microprocessor in the input device to perform comparator functions, thus eliminating the need for external comparator circuitry. At least one light-emitting element in the input device emits light pulses, and these light pulses are selectively received by a light-detecting element. A notched encoder wheel separates the light-emitting element from the light-detecting element, allowing various amounts of light to be received by the light-detecting element depending on whether a notch separates the two elements. The microprocessor loads a sample of the output from the light-detecting element: a first sample taken at a selected time value and a second sample taken at twice the selected time value. The second sample is used for quadrature calculations used in determining cursor movement on a video display device. The first sample is retrieved by the microprocessor and determined if it is a digital '1' signal. If it is, then the selected time value is decremented by one sampling period.