Disk-flutter servo control in rotating storage system with optimum disk thickness
US6339512B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 25, 1999 |
| Grant date | Jan 15, 2002 |
| Priority date | — |
| Expiry date | Mar 25, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B21/21
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A hard disk has a servo loop and a rotating storage medium. The rotating storage medium has one or more significant flutter modes at frequencies below a zero cross frequency of a rejection transfer function of the servo loop. The effect of the forgoing is to allow the servo loop to better track a rotating medium that is subject to significant flutter. Peak filters with frequency bands that substantially overlap frequency bands of the significant flutter modes can also be added to the servo loop to further improve tracking. Multiple narrow band filters with frequency bands overlap can be used to cover the spectrum of a single flutter mode. Two lag-lead filters, the frequency responses of which overlap can be used to cover two adjacent significant flutter modes. At frequencies intermediate to the two adjacent flutter, modes, the lead caused by one filter, will be cancelled by the lag caused by the second.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.