ITERATIVE DATA STORAGE READ CHANNEL ARCHITECTURE HAVING DROPOUT MITIGATION

摘要

According to one embodiment, a magnetic medium's readback signal samples are processed iteratively to provide dropout mitigation for a read channel by feeding the decoder output decisions back to the read channel front end where they are used to drive the decision-aided digital signal processing functions and control loops. Since data decisions provided by the decoder are typically more reliable than those provided by the detector, a significant performance improvement is obtained. A more reliable operation of the digital front-end signal processing functions in turn allows improvements to the reliability of the decoded data. Usage of Error Correcting Code (ECC) schemes that are soft decodable makes the read channel technique, described according to various embodiments herein, particularly efficient.

主权项

1. A system for dropout mitigation in an iterative read channel, the system comprising a processor and logic integrated with and/or executable by the processor, the logic being configured to:
execute dropout detection on a block of signal samples to detect one or more dropout events employing a set of decisions provided by a detector executing a detection algorithm; execute one or more additional digital front-end (DFE) functions on the block of signal samples employing the set of decisions provided by the detector executing the detection algorithm; execute a decoding algorithm of an error correcting code (ECC) on the signal samples using a decoder employing the set of decisions provided by the detector to generate a set of decisions provided by the decoder; store the signal samples, the set of decisions provided by the detector, and the set of decisions provided by the decoder; and in an iterative process until a maximum number of iterations has been reached or a valid codeword is produced:
execute dropout detection on the signal samples to detect one or more dropout events employing the set of decisions provided by the decoder;selectively filter the signal samples during a duration of each of the detected dropout events;execute the one or more DFE functions on the signal samples employing the set of decisions provided by the decoder;execute the detection algorithm on the signal samples using the detector employing the set of decisions provided by the decoder to regenerate the set of decisions provided by the detector;execute the decoding algorithm of the ECC using the set of decisions provided by the detector to regenerate the set of decisions provided by the decoder;output decoding information relating to the signal samples when the decoding algorithm produces a valid codeword, wherein the decoding information relating to the signal samples includes a pointer to each of the one or more detected dropout events and a duration of each of the one or more detected dropout events; andstore the signal samples, the set of decisions provided by the detector, the set of decisions provided by the decoder, and the decoding information relating to the signal samples when the decoding algorithm does not produce a valid codeword.