Read channel generating absolute value servo signal
US6594103B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 12, 1999 |
| Grant date | Jul 15, 2003 |
| Priority date | — |
| Expiry date | Nov 12, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B5/59611
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A servo control system and method controls systems at least partially on the basis of an observable variable that has an absolute value functional relationship with the controlled variable and does not change sign for positive and negative variations from a nominal value. The control system and method find particularly advantageous application in magnetic storage hard disk drive systems because the system allows such hard disk drives to perform servo operations such as track following on the basis of the data signals being read from the track. A particularly useful source of the absolute value observable variable is a read channel chip that performs decoding of data recovered from the disk. Error measures are developed as the data signals from the disk are processed and decoded, including error measures from the slicer used in an adaptive equalization process and from the data decoder, which may be a Viterbi decoder. One or more of these error measures is provided to an output terminal of the read channel chip for use with an absolute value control system and method.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.