Equalization for sample value estimation and sequence detection in a sampled amplitude read channel
US5585975A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 17, 1994 |
| Grant date | Dec 17, 1996 |
| Priority date | — |
| Expiry date | Nov 17, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B20/10074
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In a sampled amplitude magnetic read channel, pulses in an analog signal corresponding to flux transitions on a magnetic medium are sampled and equalized into a first equalization for estimating sample values and into a second equalization for sequence detection of digital data. A gain and phase error detector generate respective error signals corresponding to the difference between estimated and actual sample values. Gain control and timing recovery use the error signals to adjust the amplitude and sampling frequency/phase of the analog read signal. A pair of programmable discrete time filters equalize the signal samples into the desired equalization. In a first embodiment, the signal samples are equalized to PR4 for estimating sample values and to EPR4 for sequence detection. A slicer processes the PR4 equalized sample values to generate the estimated sample values. The gain and phase error detectors generate the corresponding error signals according to a minimum mean squared error stochastic gradient algorithm. In a second embodiment, the signal samples are equalized to EPR4 for estimating sample values and to EEPR4 for sequence detection. A pulse detector processes the EPR4 equ…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.