Servo system for disk-flutter in rotating storage systems
US6487028B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 25, 1999 |
| Grant date | Nov 26, 2002 |
| Priority date | — |
| Expiry date | Mar 25, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B5/59633
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In order to handle platter flutter in a hard disk operated at high speed (e.g. 10,000 RPM) and maintain tracking of read/write head, peak filters are added to a head tracking servo feedback loop. In some embodiments, several lag-lead type peak filters centered at a plurality of flutter mode frequencies are provided to process a Position Error Signal (PES) read from the read/write head. The several filter are preferably arranged in series (i.e. to operate on the PES sequentially), alternatively the filters can be arranged in parallel. Phase lags and leads caused by the several filters partially cancel at frequencies intermediate center frequencies of the several filters. According to another embodiment two or more, preferably three narrow band filters are used to cover the spectrum of each flutter mode. In a configuration mode, a spectrum of the flutter modes can be obtained and used to set the center frequencies, and bandwidths of filters used to filter out the flutter modes.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.