Hitachi Global Storage Technologies Netherlands B.v.

Christopher A Gimenez

Jr-Yi Shen

Jen-Yuan Chang

Robert P Harshberger, Jr

A system for reducing written-in high-frequency repeatable run-out track mis-registration occurring during writing of servo information onto a hard disk implementable in a hard disk drive is described. The system includes an excitation frequency adjuster enabled to adjust excitation frequencies away from mechanical modes to provide desired rotation speed of a servo track writer. The mechanical modes are present in said hard disk drive. The system also includes an excitation level adjuster enabled to adjust excitation level to provide a desired DC gain level associated with a motor controller of the servo track writer. The system further includes an excitation frequency content adjuster enabled to adjust excitation frequency content to provide desired current profile of the motor controller, such that a reduction of written-in high frequency repeatable run-out track mis-registration is realized.

Method and system for optimized servo track writing motor current profile to reduce written-in high-frequency repeatable runout track mis-registration

A method for reducing written-in high frequency repeatable run out track mis-registration of a hard disk is described. The method includes adjusting the excitation frequencies away from mechanical modes to provide desired rotating speed of a servo track writer. The mechanical modes are relative to said hard disk drive. The method further includes adjusting excitation levels to provide desired DC gain level associated with a motor controller of the servo track writer, wherein instances of the written-in high frequency repeatable run out track mis-registration are reduced.

Method and system for optimizing servo track writing motor current profile to reduce written-in high-frequency repeatable runout track mis-registration

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San Jose, CA, United States of America

Christopher A Gimenez