Servo control in a patterned-media magnetic recording disk drive using a reference table
US8625229B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 10, 2012 |
| Grant date | Jan 7, 2014 |
| Priority date | — |
| Expiry date | Jul 13, 2032 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B5/59666
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A patterned-media magnetic recording disk drive has head positioning servo sectors on the disk that do not contain special patterns but merely use the same type of dots that are used for data. The “data” dots in angularly spaced sectors of the data tracks function as the servo sectors and are denoted as D-servo regions. The D-servo regions extend across an annular band of the disk, which may be a bootstrap band for self-servowriting. The dots in the annular band are randomly magnetized so that each track in each D-servo region provides a generally random readback signal at the data frequency. The precise radial and circumferential position of the read/write head within a D-servo region is determined by comparing the readback signal with a set of reference signal waveforms from a look-up reference table and finding the reference signal waveform that matches the readback signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.