US 6,889,154 B2 · Method and apparatus for calibrating data-dependent noise prediction

Abstract

Disclosed herein is an apparatus and method of calibrating the parameters of a Viterbi detector 138 in which each branch metric is calculated based on noise statistics that depend on the signal hypothesis corresponding to the branch. An offline algorithm for calculating the parameters of data-dependent noise predictive filters 304A-D is presented which has two phases: a noise statistics estimation or training phase, and a filter calculation phase. During the training phase, products of pairs of noise samples are accumulated in order to estimate the noise correlations. Further, the results of the training phase are used to estimate how wide (in bits) the noise correlation accumulation registers need to be. The taps [t2[k], t1[k], t0[k]] of each FIR filter are calculated based on estimates of the entries of a 3-by-3 conditional noise correlation matrix C[k] defined by Cij[k]=E(ni−3nj−3|NRZ condition k).

Claims6

Dependent claims

A method of calibrating a Viterbi detector, said Viterbi detector comprising at least one noise predictive filter, said method comprising:

(a) obtaining noise samples in a training phase;
(b) averaging said noise samples;
(c) estimating entries of a 3-by-3 conditional noise matrix C[k] defined by
C
ij
[
k
]
=
E
(
n
i
-
3
⁢
n
j
-
3
|
NRZ
⁢
⁢
condition
⁢
⁢
k
)
;
and
(d) calculating at least one tap of said at least one noise predictive filter based on said estimated entries.

29 more elements

Dependencies are inferred from the claim text.

Facts

Application

10/402,033Filed 28 Mar 2003 · us provisional application

Priority

18 Apr 2002

Published

US 2004/0032683 A119 Feb 2004

Granted

3 May 2005

Term ends

Not estimatedThe source records don’t support an estimate.

Classification11 codes

H03M 13/6343
Joint error correction and other techniques: error control coding in combination with techniques for partial response channels, e.g. recording
G11B 20/10009
Digital recording or reproducing: improvement or modification of read or write signals
G11B 20/10046
Improvement or modification of read or write signals: filtering or equalising, e.g. setting the tap weights of an FIR filter
G11B 20/10055
Filtering or equalising, e.g. setting the tap weights of an FIR filter: using partial response filtering when writing the signal to the medium or…

Method and apparatus for calibrating data-dependent noise prediction

Life of this patent

Method and apparatus for calibrating data-dependent noise prediction

Life of this patent

Abstract

Claims6