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:
Jul. 15, 2003
Filed:
Nov. 12, 1999
Alvin M. Despain, Pacific Palisades, CA (US);
R. Stockton Gaines, Pacific Palisades, CA (US);
Acorn Technologies, Inc., Pacific Palisades, CA (US);
Abstract
A servo control system and method controls systems at least partially on the basis of an observable variable that has an absolute value functional relationship with the controlled variable and does not change sign for positive and negative variations from a nominal value. The control system and method find particularly advantageous application in magnetic storage hard disk drive systems because the system allows such hard disk drives to perform servo operations such as track following on the basis of the data signals being read from the track. A particularly useful source of the absolute value observable variable is a read channel chip that performs decoding of data recovered from the disk. Error measures are developed as the data signals from the disk are processed and decoded, including error measures from the slicer used in an adaptive equalization process and from the data decoder, which may be a Viterbi decoder. One or more of these error measures is provided to an output terminal of the read channel chip for use with an absolute value control system and method.