Sequence (Viterbi-equivalent) decoding

Author

Schneider, Richard C.

Author_Institution

IBM Corp., Tucson, AZ, USA

Volume

24

Issue

6

fYear

1988

fDate

11/1/1988 12:00:00 AM

Firstpage

2539

Lastpage

2541

Abstract

A decoder for magnetic recording that is applicable to both a (0,3) code equalized and dicode channel and a (1,7) code equalized to a class-IV partial response channel is described. The decoder makes a decision after examining samples from a finite number of bits rather than one bit at a time. It is functionally equivalent to a specific type of Viterbi decoder. The decoder algorithm is significantly simplified by using knowledge of the run-length code constraints. Hardware sharing further reduces implementation complexity. A detailed description of the sequence-decoder algorithm and hardware implementation is given. Test results for both the (0,3) and (1,7) modulation codes at recorder densities of 24690 and 30480 fci (21946 and 40640 bpi) are included. Comparisons are made between the sequence-decoder and peak and threshold detection (bit-by-bit hard decision) for both the actual recording channels and a linear-filter channel simulator

Keywords

decoding; magnetic recording; (0,3) code; (1,7) code; Viterbi decoder; actual recording channels; bit-by-bit hard decision; decoder algorithm; hardware implementation; implementation complexity; linear-filter channel simulator; magnetic recording; modulation codes; peak detection; recorder densities; run-length code constraints; sequence decoder detection; sequence-decoder algorithm; threshold detection; Decoding; Equations; Hardware; Intersymbol interference; Logic; Magnetic recording; Modulation coding; Signal to noise ratio; Testing; Viterbi algorithm;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/20.92167

Filename

92167