US 5,493,454 A · Write precompensation optimization in a PRML channel using a selected PRML signal level

Abstract

Write precompensation optimization for a partial response maximum likelihood ("PRML") magnetic recording channel adapted to a mass production environment. Optimal write precompensation may be determined by writing a tribit data pattern known to produce worst case nonlinear transition shift ("NLTS") onto a magnetic recording medium; reading back the recorded data pattern; and calculating the mean-squared error ("MSE") for one or more of the equalized data sample levels associated with the PRML channel to be optimized. The writing and reading back process is repeated with varying amounts of precompensation applied to the written pattern. The optimal amount of write precompensation is determined either by minimizing the MSE for a selected sample level or by minimizing MSE between the middle and the upper or lower of the ternary PRML sample levels.

Claims17

Dependent claims

A method of optimizing write precompensation in a PRML magnetic recording channel comprising the steps of:

(a) applying a value of write precompensation to a predetermined data pattern thereby creating a precompensated data pattern;
(b) writing said precompensated data pattern onto a magnetic recording medium;
(c) reading said precompensated data pattern from said magnetic recording medium and generating therefrom a read signal;
(d) inputing said read signal into said PRML channel, said PRML channel having an output providing a plurality of PRML signal levels;
(e) sampling said read signal to obtain a series of read signal samples;
(f) selecting one of said plurality of PRML signal levels;
(g) calculating a mean-squared error value of read signal samples from said selected one of said PRML signal levels;
and
(h) repeating said steps of applying, writing, reading, inputing, sampling and calculating for said selected PRML signal level using a new value of write precompensation for each repetition until a minimum mean-squared error value of read signal samples from said selected PRML signal level is obtained.

6 more elements

A method of optimizing write precompensation in a PRML magnetic recording channel comprising the steps of:

(a) applying a value of write precompensation to a predetermined data pattern thereby creating a precompensated data pattern;
(b) writing said precompensated data pattern onto a magnetic recording medium;
(c) reading said precompensated data pattern from said magnetic recording medium and generating therefrom a read signal;
(d) inputing said read signal into said PRML channel, said PRML channel having an output providing a plurality of PRML signal levels;
(e) sampling said read signal to obtain a series of read signal samples;
(f) selecting a first of said plurality of PRML signal levels;
(g) calculating a mean-squared error value of said read signal samples from said first selected PRML signal level;
(h) selecting a second of said plurality of PRML signal levels;
(i) repeating said steps of reading, inputing, sampling, and calculating to obtain a mean-squared error value of said read signal samples from said second selected PRML signal level;
and
(j) repeating said steps of applying, writing, reading, inputing, sampling and calculating a mean-squared error value of said read signal samples from said first selected PRML signal level, and said steps of reading, inputing, sampling and calculating a mean-squared error value of read signal samples from said second selected PRML signal level using a new value of write precompensation for each repetition until a difference between said mean-squared error value of read signal samples from said first selected PRML signal level and said mean-squared error value of read signal samples from said second PRML signal level is minimized.

8 more elements

Dependencies are inferred from the claim text.

Write precompensation optimization in a PRML channel using a selected PRML signal level

Life of this patent

Write precompensation optimization in a PRML channel using a selected PRML signal level

Life of this patent

Abstract

Claims17