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:
Apr. 13, 1993
Filed:
Mar. 01, 1991
Michael D Sidman, Colorado Springs, CO (US);
Digital Equipment Corporation, Maynard, MA (US);
Abstract
Methods for writing and detecting servo positioning dibit transitions on a magnetic data surface having circular tracks with two magnetic polarizations, the transitions each having a radial extent greater than the spacing between adjacent centerlines. The transitions are written by first prepolarizing the magnetic surface to a first polarization and then writing a second polarization followed by a first polarization and not writing when the write head passes a previously written transition in an adjacent track. The transitions are detected by qualifying the detection means when the sensed servo signal exceeds a threshold amplitude corresponding to a first polarization and detecting the crossing by the sensed servo signal of a second threshold corresponding to the transition to a second polarization.