Non-Linear Digitization for a Viterbi Detector
Original Publication Date: 1985-Jul-01
Included in the Prior Art Database: 2005-Feb-18
In a detector which digitizes samples taken from a two-level PR4 magnetic channel, and which uses a Viterbi algorithm to resolve ambiguity, the cost of the analog-to-digital converter and the complexity of the logic supporting the Viterbi algorithm can be reduced by making the converter non-linear and of limited range. The proposed converter divides the signal range into L+1 intervals, separated by L reference levels which are not evenly spaced apart. L is a measure of the cost of the converter, and Log(L) a measure of the cost of the logic supporting the Viterbi algorithm. The idea can be extended to other types of channel. A detector which digitizes the samples before decoding introduces a digitization error. The minimum precision needed in the digitization requires two thresholds, Å0.