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:
Oct. 29, 1991
Filed:
Sep. 01, 1989
Paul Sagues, Berkeley, CA (US);
Vernon E Muhr, El Cerrito, CA (US);
Berkeley Process Control, Inc., Richmond, CA (US);
Abstract
Method and apparatus for measuring the velocity, whether rotary or reciprocating, of a servo shaft driven cyclically by a motor, without employing a tachmometer, while maintaining accuracy despite environmental electrical noise. From movement of the shaft a pair of overlapping square-wave signals in quadrature are produced with transition expressible in Gray Code for each cycle. A clock continuously produces a large number of evenly spaced clock pulses constituting a series of consecutive sample intervals. A signed value representing the algebraic sum of all the quadrature transitions occurring during a sample interval is determined and stored. The number of clock pulses between two quadrature transitions, each transition being the last qualified transition of the two most recent sample intervals having transitions is determined. A computer divides the sample intervals by the number of clock pulses which occurred between the selected quadrature transitions.