Decimation DC offset control in a sampled amplitude read channel
US5583706A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 17, 1994 |
| Grant date | Dec 10, 1996 |
| Priority date | — |
| Expiry date | Nov 17, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B19/04
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In a sampled amplitude read channel for magnetic recording, a nonlinear discrete time decimation filter in a negative feed back loop adjusts a DC offset in an analog read signal from a magnetic read head without distorting the read signal. In sampled amplitude recording, adding the samples of an isolated positive pulse to the samples of an isolated negative pulse generates the DC offset of the discrete time sample values. A decimation filter adds the sample values from a positive pulse to the sample values of a negative pulse in order to detect and pass the DC offset in the read signal. The detected discrete time DC offset from the discrete time decimation filter is converted into an analog DC offset signal and subtracted from the analog read signal in a negative feedback loop. A running average decimation filter removes the DC offset during acquisition, and a decision-directed decimation filter removes the DC offset during tracking.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.