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US 8,015,499 B2Granted
Decoder and reproducing device
AssigneeFujitsu Limited
InventorToshikazu Kanaoka
Life of this patent
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Abstract
A reproducing device performs decoding by propagating the reliability, and detects micro medium defects to correct the reliability information. The decoder has an internal decoder, external decoder and a defect detector which calculates a moving average value of a soft-input signal, acquires a scaling factor from this, and manipulates the reliability information of the internal decoder. Since micro-defects can be detected accurately and the reliability information of the internal decoder is manipulated, error propagation due to micro defects can be suppressed.
Claims18
A decoder, comprising:
- a soft-input soft-output decoder for decoding channel reproducing signals which have inter-symbol interference;
- a soft-input decoder for decoding a soft output of the soft-input soft-output decoder;
- and
- a weighting computing unit for detecting both sided amplitude fluctuation of a soft-input signal of the soft-input soft-output decoder, and outputting a weight value according to a drop in amplitude,
- wherein a soft output value of the soft-input soft-output decoder decreases the soft output value by the weight value, and a decoding process is performed by propagating reliability information between the soft-input soft-output decoder and the soft-input decoder, and
- wherein the weighting computing unit comprises:
- an absolute value encoding section for reflecting the soft-input signal at an amplitude center value;
- a moving average computing section for computing a moving average value in a predetermined range;
- a normalization computing section for dividing the moving average value by an average value of all the absolute value signals;
- and
- a weighting generation section for generating the weight value as “1” when the normalization computing value is “1” or more, and as the normalization computing value when the normalization computing value does not exceed “1”.
8 more elements
A reproducing device, comprising:
- a waveform equalizer for equalizing a reproducing waveform into channel reproducing signals which have inter-symbol interference;
- a soft-input soft-output decoder for decoding the channel reproducing signals;
- a soft-input decoder for decoding external encoding;
- and
- a weighting computing unit for detecting both sided amplitude fluctuation of a soft-input signal of the soft-input soft-output decoder, and outputting a weight value according to a drop in amplitude,
- wherein a soft output value of the soft-input soft-output decoder is decreased by the weight value, and a decoding process is performed by propagating reliability information between the soft-input soft-output decoder and the soft-input decoder,
- and wherein the weighting computing unit comprises:
- an absolute value encoding section for reflecting the soft-input signal at an amplitude center value;
- a moving average computing section for computing a moving average value in a predetermined range;
- a normalization computing section for dividing the moving average value by an average value of all the absolute value signals;
- and
- a weighting generation section for generating the weight value as “1” when the normalization computing value is “1” or more, and as the normalization computing value when the normalization computing value does not exceed “1”.
9 more elements
Dependencies are inferred from the claim text.