Systems and methods for media defect detection utilizing correlated DFIR and LLR data
AssigneeAgere Systems Inc.
InventorsWeijun Tan, Hongwei Song, Shaohua Yang
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Abstract
The present invention provides systems and methods for detecting a media defect. A circuit providing a hard output and a soft output is used with the hard output and the soft output being combined and the product compared with a threshold. Based at least in part on the comparison, a media defect may be identified.
Claims23
A method for detecting a media defect, the method comprising:
- deriving a data input from a medium;
- performing a maximum a posteriori detection on the data input, wherein a non-return to zero output and an log-likelihood ratio output are produced;
- correlating a product of the non-return to zero output with a product of the log-likelihood ratio output, wherein a correlated output is produced;
- comparing the correlated output with a threshold value;
- and
- asserting a media defect output based at least in part on the comparison of the correlated output with the threshold value.
A media defect detection system, wherein the media defect detection system comprises:
- a data signal;
- a maximum a posteriori detector, wherein the maximum a posteriori detector provides an non-return to zero output and an log-likelihood ratio output based at least in part on the data signal;
- a correlation circuit, wherein the correlation circuit correlates the non-return to zero output with the log-likelihood ratio output and provides a correlated output;
- and
- a comparator, wherein the comparator receives the correlated output and compares the correlated output with a threshold value.
A data processing system, the data processing system comprising:
- a medium;
- an analog signal derived from the medium;
- an analog to digital converter, wherein the analog to digital converter creates a digital signal from the analog signal;
- a media defect detector, wherein the media defect detector includes:
- a maximum a posteriori, wherein the maximum a posteriori detector provides a non-return to zero output and an log-likelihood ratio output based at least in part on the digital signal;
- a correlation circuit, wherein the correlation circuit correlates the non-return to zero output with the log-likelihood ratio output and provides a correlated output;
- and
- a comparator, wherein the comparator receives the correlated output and compares the correlated output with a threshold value, and
- a defect signal generator, wherein the defect signal generator outputs a media defect flag based at least in part on the output of the comparator and indicating a defective portion of the medium.
A method for detecting a media defect, the method comprising:
- receiving a data input from a medium;
- performing a data detection on the data input, wherein a hard output and a soft output are provided by one data processing circuit;
- correlating a product of the hard output with a product of the soft output to yield a correlated output;
- comparing the correlated output with a threshold value;
- and
- asserting a media defect output based at least in part on the comparison of the correlated output with the threshold value.
A media defect detection system, wherein the media defect detection system comprises:
- a data signal;
- a detector circuit operable to provide both a hard output and a soft output based at least in part on the data signal;
- a correlation circuit, wherein the correlation circuit is operable to correlate the hard output with the soft output to yield a correlated output;
- and
- a comparator, wherein the comparator is operable to receive the correlated output and to compare the correlated output with a threshold value.
Dependencies are inferred from the claim text.