Method and apparatus for data detection for PRML data channels
US5949831A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 21, 1997 |
| Grant date | Sep 7, 1999 |
| Priority date | — |
| Expiry date | May 21, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L2025/03369
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method and apparatus are provided for data detection for a partial-response maximum-likelihood (PRML) data detection channel in a direct access storage device. A class-IV partial response (PR4) signal is applied to a PR4 Viterbi detector to provide a PR4 Viterbi output and is applied to a first matching delay circuit to provide a delayed PR4 signal. The PR4 Viterbi output is subtracted from the delayed PR4 signal and a resulting signal is applied to a first filter having a frequency response of 1/(1-.alpha.D.sup.2). The filtered output signal is applied to a second filter providing a second filtered output signal. The PR4 Viterbi output is applied to a second matching delay circuit to provide a delayed PR4 Viterbi output signal. The delayed PR4 Viterbi output is corrected responsive to the second filtered output signal. The first filter is an infinite impulse response (IIR) filter and the filtered output signal represents whitened noise and modified PRML error events. The second filter is a matched filter used to identify dominant error events.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.