Dynamic magnetic information storage or retrieval – General recording or reproducing – Specifics of equalizing
Reexamination Certificate
2007-04-25
2010-12-14
Mercedes, Dismery E (Department: 2627)
Dynamic magnetic information storage or retrieval
General recording or reproducing
Specifics of equalizing
C360S029000, C360S031000, C360S039000
Reexamination Certificate
active
07852589
ABSTRACT:
Embodiments in accordance with the present invention provide a magnetic disk drive capable of achieving error recovery stably in a simple configuration in the event of thermal asperity (TA) and minimizing the error recovery time required, and a method for controlling the disk drive. According to one embodiment, if TA occurs, a cutoff frequency of a high-pass filter to which a data read signal is input is first increased and a loop gain of a low-order finite impulse response (FIR) filter connected in series to an FIR filter is also increased as high as possible. Next, a Viterbi decoder to which a signal is input from the low-order FIR filter provides feedback to the low-order FIR filter so that an input signal error becomes a minimum. Tap coefficients of the low-order FIR filter are thus optimized.
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Ikeda Masaomi
Koizumi Masahiko
Maeda Hideaki
Matsui Takao
Nakao Kohji
Hitachi Global Storage Technologies - Netherlands B.V.
Mercedes Dismery E
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