Detecting servo defects in a disc drive
US5930068A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 30, 1996 |
| Grant date | Jul 27, 1999 |
| Priority date | — |
| Expiry date | Sep 30, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B5/596
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Apparatus and method for detecting servo defects in a disc drive, the servo defects providing false indications of the position of a disc drive head with respect to a selected track. During use of a position error signal (PES) to position the head with respect to the selected track, the PES comprising a sequence of PES samples, the disc drive determines a first difference term as a selected combination of a first set of PES samples. A second, subsequent difference term is also generated as a selected combination of a second set of PES samples, the second set of PES samples including at least one PES sample which does not appear in the first set of PES samples. The magnitudes of the first and second difference terms are compared to a predetermined threshold, and a servo defect is detected at such time that both the first and second difference terms exceed the predetermined threshold and the first difference term exceeds the second difference term. Additionally, at such time that the first difference term exceeds the predetermined threshold and the second, subsequent difference term does not, the disc drive determines whether a servo defect flag has previously been set indicative of …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.