Adaptive equalization in a sub-sampled read channel for a disk storage system
US5966415A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 13, 1997 |
| Grant date | Oct 12, 1999 |
| Priority date | — |
| Expiry date | Jun 13, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L2025/03617
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A sampled amplitude read channel for disk storage systems is disclosed which asynchronously sub-samples an analog read signal significantly below the Nyquist rate (the baud rate) in order to increase the effective data rate without increasing the frequency of the sampling device. Interpolated timing recovery up-samples the asynchronous samples to generate sample values synchronized to the baud rate, and a Viterbi sequence detector detects the recorded digital data from the synchronous sample values. To compensate for the time-varying characteristics of the recording device, a discrete-time equalizer adaptively equalizes the asynchronous sample values using a least mean square (LMS) adaptive algorithm, EQU W.sub.k+1 =W.sub.k -.mu..multidot.e.sub.k .multidot.X.sub.k, where W.sub.k is a vector of FIR filter coefficients, .mu. is a programmable gain, e.sub.k is a sample error between the FIR filter's actual output and a desired output, and X.sub.k is a vector of samples values from the FIR filter input.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.