Adaptive data detection on a nonlinear channel
AssigneeInternational Business Machines Corporation
InventorsRoy Cideciyan, Simeon Furrer, Mark Alfred Lantz
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Abstract
A data storage system comprises: a head configured to produce a signal representing data stored on a storage medium; an estimator configured to determine an estimated signal comprising a superposition of an estimated linear portion of a partial-response equalizer output and an estimated nonlinear portion of the signal; a bank of noise whitening filters configured for filtering a difference between the signal and the estimated signal; a branch metric calculator configured to calculate branch metrics based on the filtered signal; and an adaptive data-dependent noise-predictive maximum likelihood sequence detector configured to generate an output stream representing the data based on the one or more branch metrics.
Claims18
A data storage system, comprising:
- a head configured to produce a signal representing data stored on a storage medium;
- an estimator configured to determine an estimated signal from the signal, the estimated signal comprising a superposition of an estimated linear portion of a partial-response equalizer output and an estimated nonlinear portion of the signal;
- a bank of noise whitening filters configured to apply one or more noise whitening filters to a difference between the signal and the estimated signal to produce a filtered signal;
- a branch metric calculator configured to perform one or more branch metric calculations on a metric input signal based on the filtered signal to generate one or more branch metrics;
- and
- an adaptive data-dependent noise-predictive maximum likelihood sequence detector configured to generate an output stream representing the data based on the one or more branch metrics.
A method comprising:
- receiving, from a head, a signal representing data stored on a storage medium;
- receiving, from an estimator, an estimated signal comprising a superposition of an estimated linear portion of a partial-response equalizer output and an estimated nonlinear portion of the signal;
- applying one or more noise whitening filters to a difference between the signal and the estimated signal to produce a filtered signal;
- performing one or more branch metric calculations on a metric input signal based on the filtered signal to produce one or more branch metrics;
- generating an output stream representing the data based on the one or more branch metrics;
- and
- based on the signal and the output stream, updating the estimated signal.
A computer program product comprising a computer readable storage medium having program instructions embodied therewith, the program instructions being executable by a processing circuit to cause the processing circuit to:
- receive, from a head, a signal representing data stored on a storage medium;
- receive, from an estimator, an estimated signal comprising a superposition of an estimated linear portion of a partial-response equalizer output and an estimated nonlinear portion of the signal;
- apply one or more noise whitening filters to a difference between the signal and the estimated signal to produce a filtered signal;
- perform one or more branch metric calculations on a metric input signal based on the filtered signal to produce one or more branch metrics;
- generate an output stream representing the data based on the one or more branch metrics;
- and
- based on the signal and the output stream, update the estimated signal.
Dependencies are inferred from the claim text.