Simplified branch metric for reducing the cost of a trellis sequence detector in a sampled amplitude read channel
US6216249A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 3, 1999 |
| Grant date | Apr 10, 2001 |
| Priority date | — |
| Expiry date | Mar 3, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M13/6502
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A sampled amplitude read channel for use in disk storage systems (magnetic or optical) is disclosed comprising a simplified branch metric calculator for use in a trellis sequence detector. Instead of computing the traditional Euclidean branch metric as the squared difference between the actual signal sample and the expected signal sample of the target partial response, the present invention computes a simplified branch metric which is then saturated in order to reduce the number of bits required to calculate and store the branch metrics, thereby simplifying the branch metric calculators as well as reducing the add-compare-select (ACS) circuitry for each state in the trellis. Furthermore, the saturation technique of the present invention is substantially data independent meaning that the saturation threshold is essentially independent from the signal samples used to compute the branch metric.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.