Noise predictive maximum likelihood (NPML) detection methods and apparatus based thereon
US6104766A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 17, 1996 |
| Grant date | Aug 15, 2000 |
| Priority date | — |
| Expiry date | Sep 17, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L25/497
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The invention is family of noise predictive maximum liklihood (NPML) symbol detectors that are particularly useful in direct access storage devices. Various embodiments representative of the family of detectors are described. In general, the NPML detectors include a sequence detector with imbedded feedback which may be preceded by a filter, e.g., a prediction error filter. The sequence of detectors, which may be Viterbi detectors, have an imbedded filter whose coefficients are determined by the convolution of the partial response (PR) or generalized PR function with the predictor coefficients and do not require multiplications and, thus, allows a simple RAM look-up for intersymbol-interference ISI cancelation. In one class of embodiments, the NPML detector comprises a prediction error filter of length N, cascaded with a sequence detector having 2.sup.K states, and a feedback filter imbedded in the sequence detector, having a length N+P-K, where P is length of the generalized PR shaping polynomial (P=2 yields PR4), and 0.ltoreq.K.ltoreq.N+P.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.