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. 12, 1999
Filed:
Aug. 07, 1997
Karl Arnold Belser, San Jose, CA (US);
Wayne Leung Cheung, San Jose, CA (US);
International Business Machines Cororation, Armonk, NY (US);
Abstract
Servo pattern bursts are recorded with two frequencies that are detected using heterodyne detection with oscillators at the same frequency as the respective recorded frequencies. The two frequencies are selected to be orthogonal so the sensed servo pattern of one frequency is zero when detected with the detecting circuitry of the other frequency. The servo pattern bursts of the two frequencies are placed close together on the disk so they are sensed simultaneously so that, with orthogonality processing, a PES signal from a three phase pattern is sufficient to provide a robust linear signal, thereby eliminating one of the bursts from a quadrature pattern and reducing the disk surface area needed in each track for the servo pattern by 25% or more.