Disk drive margining read channel by biasing log-likelihood ratios of an iterative decoder
AssigneeWestern Digital Technologies, Inc.
InventorsAlvin J. Wang, Patrick J. Lee, Manmohan K. Sharma
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Abstract
A disk drive is disclosed comprising a head actuated over a disk comprising a plurality of data tracks. A read signal emanating from the head is sampled to generate read samples, and first log-likelihood ratios (LLRs) are generated in response to the read samples. The first LLRs are biased to generate biased LLRs, and the biased LLRs are decoded into a data sequence, wherein the biased LLRs increase an error rate of the data sequence.
Claims22
A disk drive comprising:
- a disk comprising a plurality of data tracks;
- a head actuated over the disk;
- and
- control circuitry operable to:
- sample a read signal emanating from the head to generate read samples;
- generate first log-likelihood ratios (LLRs) in response to the read samples;
- bias the first LLRs to generate biased LLRs;
- and
- decode the biased LLRs into a data sequence, wherein the biased LLRs increase an error rate of the data sequence.
A method of operating a disk drive comprising a head actuated over a disk comprising a plurality of data tracks, the method comprising:
- sampling a read signal emanating from the head to generate read samples;
- generating first log-likelihood ratios (LLRs) in response to the read samples;
- biasing the first LLRs to generate biased LLRs;
- and
- decoding the biased LLRs into a data sequence, wherein the biased LLRs increase an error rate of the data sequence.
Dependencies are inferred from the claim text.