Dynamic magnetic information storage or retrieval – Automatic control of a recorder mechanism – Controlling the head
Reexamination Certificate
2008-01-01
2008-01-01
Wong, K. (Department: 2627)
Dynamic magnetic information storage or retrieval
Automatic control of a recorder mechanism
Controlling the head
Reexamination Certificate
active
07315430
ABSTRACT:
Embodiment of the invention inhibit an effect of repeatable runout errors without expanding servo data areas of the magnetic disk. With regard to low frequency components of positional information read by a magnetic head, which are substantially equivalent to a rotational frequency of a magnetic disk, a servo controller according to one embodiment includes: a peak filter for removing such low frequency components from the positional information; a correction module for correcting the positional information by using repeatable runout compensation data; a phase correction circuit for calculating the amount of control based on an output of the correction module; and an adding circuit for adding an output of the peak filter and an output of the phase correction circuit. The servo controller controls positioning of the magnetic head by calculating an amount of positioning control of the magnetic head based on the positional information and adding it to the amount of control calculated based on the positional information and the repeatable runout compensation data.
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Duncan Patrick
Hitachi Global Storage Technologies - Netherlands B.V.
Townsend and Townsend / and Crew LLP
Wong K.
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