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:
Mar. 24, 1992
Filed:
Mar. 07, 1991
Michael D Sidman, Colorado Springs, CO (US);
Digital Equipment Corporation, Maynard, MA (US);
Abstract
A magnetic disk drive wherein the radial position of a sensing head being positioned by a servo system is ascertained from the sensing of servo signals arranged in successive groups of tracks on a disk surface, each of the tracks in a group being of a different track type and said servo signals being in relative circumferential positions according to the track types of the tracks containing those signals. The sensed servo signals are linearly related to the radial position of the head relative to the track containing the corresponding servo signal, the linear relationship extending over a radial distance of a plurality of tracks, are amplified by a gain controlled amplifier, and are gated to respective detectors corresponding to different track types. The amplifier is controlled by a gain error signal derived from comparison of the sum of the outputs of the detectors to a reference level. Combinations of the detector signals are used to position a read/write head corresponding to the sensing head over selected tracks or radial positions between tracks. The dedicated servo surface is also used for control purposes during servo writing on the data surfaces and to generate a Gray code for track identification.