Asynchronous digital demodulator and method for a null-type servo pattern
US6243224A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 15, 1999 |
| Grant date | Jun 5, 2001 |
| Priority date | — |
| Expiry date | Mar 15, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B5/59688
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An asynchronous demodulator and method is provided which determines a position error of a read head relative to a position on a medium in a storage device. The read head generates a read signal as the read head passes over a servo area on the medium. The demodulator generates a normal demodulating signal that is asynchronous with the read signal and a quadrature demodulating signal that is ninety degrees out of phase with the normal demodulating signal. The read signal is sampled to produce a series of digital read values which are multiplied by the normal demodulating signal and the quadrature demodulating signal to produce a plurality of normal and quadrature sample values. The demodulator produces the a position error magnitude and a position error direction based on the plurality of normal and quadrature sample values.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.