Servo writing a disk drive by overwriting a harmonic frequency fill pattern in the servo burst area
US7068461B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 29, 2004 |
| Grant date | Jun 27, 2006 |
| Priority date | — |
| Expiry date | Nov 29, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B5/59638
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A disk drive is disclosed comprising a disk having a plurality of servo bursts written using perpendicular magnetic recording, wherein each servo burst is written at a servo burst frequency. A fill pattern is written between the servo bursts using perpendicular magnetic recording at a frequency substantially equal to an even harmonic of the servo burst frequency, and a phase shift occurs at the transition between the servo burst and the fill pattern. A head is actuated over the disk, and a sampling device samples a read signal emanating from the head to generate a sequence of read signal sample values. Control circuitry demodulates the servo bursts from the sequence of read signal sample values by computing a single-point Discrete Fourier Transform (DFT) at the servo burst frequency.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.