Method and apparatus for switching between data and servo modes
US5642244A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 7, 1994 |
| Grant date | Jun 24, 1997 |
| Priority date | — |
| Expiry date | Jul 7, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2020/1282
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A servo gate method and apparatus to allow switching between a servo mode and a data mode in the read channel of a disk drive. The present invention uses a servo gate signal to select components and parameters in the read channel of a disk drive. The servo gate signal, when enabled, preloads appropriate registers with new values and preloads the programmable filter with new values. The servo gate signal is not limited to preloading the above values, but may be used to control many characteristics of a disk drive read channel. For example, the servo gate signal may be used to control a pulse detector amplitude voltage threshold, to select between a window comparator and a hysteresis comparator, to control a pulse detector qualification mode for either a window comparator or a hysteresis comparator, to set a hysteresis threshold time constant, to adjust the cut-off frequency and high-frequency boost of a programmable filter, to switch a raw data output, to set an AGC amplifier gain setting, to provide fast recovery from changes in offset or DC operating point changes and to set an AGC amplifier target voltage level. The servo gate signal is designed to override read gate and write ga…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.