Magnetic disk apparatus, method for reproducing magnetic recording, and method for read retry
AssigneeFujitsu Limited
InventorHiroaki Ueno
Life of this patent
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Abstract
In the case that perpendicular magnetic recording is used, when a cut-off frequency fc of a high-pass filter of a head output is small, an error rate can be improved more when a PR target having a DC component is used and, when the cut-off frequency fc is large, an error rate can be improved more when a PR target not having a DC component is used. With this fact as a logical ground, in the present invention, when TA does not occur, PR equalization is performed using the PR target having a DC component and, when TA occurs, the cut-off frequency fc is increased to cut a low frequency component of a head reproduction signal and, additionally, PR equalization is performed using the PR target not having a DC component.
Claims15
A method for reproducing magnetic recording executed in a magnetic disk apparatus, the method comprising:
- using a plurality of partial response targets.
A method for reproducing magnetic recording executed in a magnetic disk apparatus for perpendicular magnetic recording, the method comprising:
- detecting whether thermal asperity occurs;
- and
- changing, in a case that the thermal asperity occurs, a characteristic of a partial response target to a characteristic different from that used in a case that the thermal asperity does not occur.
A semiconductor integrated circuit device for reproducing magnetic recording and mounted on a magnetic disk apparatus, the semiconductor integrated circuit device comprising:
- a plurality of partial response targets.
A semiconductor integrated circuit device for reproducing magnetic recording and mounted on a magnetic disk apparatus for perpendicular magnetic recording, the semiconductor integrated circuit device comprising:
- a detecting unit for detecting whether thermal asperity occurs;
- and
- a changing unit for changing a characteristic of a partial response target to a characteristic different from that used in a case that the thermal asperity does not occur.
A method for read retry executed in a magnetic disk apparatus, the method comprising:
- changing, in a case that it is necessary to perform read retry because of occurrence of thermal asperity, a characteristic of a partial response target to execute the read retry.
A magnetic disk apparatus comprising:
- a read retry executing unit for changing, in a case that it is necessary to perform read retry because of occurrence of thermal asperity, a characteristic of a partial response target to execute the read retry.
Dependencies are inferred from the claim text.