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. 23, 1986
Filed:
Oct. 16, 1985
William G Crouse, Raleigh, NC (US);
Earl A Cunningham, Rochester, MN (US);
Albert W Vinal, Cary, NC (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
This invention utilizes a sectored servo control having dual servo tracks recorded in the servo sector. In addition, the servo sector track portions have been recorded with two 180.degree. flux reversals in each track's polarity. The tracks are generally recorded with DC recording current to set a uniform magnetic polarity. The current is switched twice, i.e., from positive and negative and back again or vice versa for each servo track within the servo sector interval. This permits separation of the sensor, amplifier and servo signal offset voltages from the main servo signal itself. Two samples of the servo control voltage are taken during the servo sector interval and the polarity reversal of the servo track is necessary to allow separation of the offset voltages from a variety of sources from the off track or servo error signal.