Method for measuring PES noise of servo patterned media
US6853514B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 11, 2002 |
| Grant date | Feb 8, 2005 |
| Priority date | — |
| Expiry date | Mar 21, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B5/59611
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method for measuring servo pattern irregularity and other servo information of pre-patterned servo media mounted on a spindle with the center of the pre-pattern tracks off center from the axis rotation of the spindle. An actuator is stepped radially while measuring the PES signals from the servo sectors of at least one highly eccentric track to form a cross track profile of the PES signals for each sector. A mathematical algorithm removes step measurement error from the data. A second mathematical algorithm removes non-repeatable random noise from the data. The amount of phase-in that radially aligns the respective cross track profiles is computed. Servo pattern written-in repeatable runout is determined by unwrapping the phase-in values to form a periodic curve.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.