Track position syncopation cancellation in a disk drive
US5041926A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 13, 1989 |
| Grant date | Aug 20, 1991 |
| Priority date | — |
| Expiry date | Nov 13, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B5/59688
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A linear or rotary disk memory drive having provision for compensating or cancelling track position syncopation. Due to interference among the magnetic fields of magnetic dibits recorded in and adjacent to a servo code field in a magnetic memory disk, magnetic field intensities are displaced, producing an indication of a track center displaced from the actual track center. A magnetic head tracking such displaced magnetic fields is consequently displaced from track center, which is unacceptable. Four phases of magnetic dibits of servo code are recorded in each of at least four consecutive circumferential frames in a memory disk, in differing servo code formats or patterns of magnetic dibits. Magnetic head servo code signals derived from the magnetic fields of these servo code magnetic dibit patterns are logically processed to produce an AC signal representing track position syncopation which is cancelled by filtering, leaving servo code signals accurately reflecting the position of the magnetic head with respect to a track center.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.