Disk drive system using multiple embedded quadrature servo fields
US5381281A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 24, 1993 |
| Grant date | Jan 10, 1995 |
| Priority date | — |
| Expiry date | Jun 24, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B21/106
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A quadrature based embedded servo control system is provided to realize a high track density, high-performance hard disk drive system. Each data sector includes a gray code field spanning the entire width of the data track and a quad-servo burst pattern having first, second, third, and fourth servo burst fields distributed along the length of a portion of the data sector. The center point of the first, second, third, and fourth servo bursts are sequentially offset from the adjacent burst by a radial distance equivalent to one-half of the data track width. The quad-servo burst pattern is used with a track-following algorithm based on the quadrature value of (A+B)-(C+D) to obtain a substantially increased servo lock range. A second gray code field extending substantially the width of the data track and second quad-servo burst pattern substantially identical to the first is provided near a mid-point in the data portion of the data sector to increase the servoing information sample rate and accuracy, thereby permitting substantially increased data track densities to be utilized.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.