Lan Duc Ngo

US Patent:

6937423, Aug 30, 2005

Filed:

Feb 6, 2004

Appl. No.:

10/773526

Inventors:

Lan V. Ngo - Garden Grove CA, US
Raffi Codilian - Irvine CA, US

Assignee:

Western Digital Technologies, Inc. - Lake Forest CA

International Classification:

G11B005/596

US Classification:

360 7702, 360 7703, 360 7707

Abstract:

A method of reducing rotational vibration effects in a disk drive by sensing vibration in a sensor and generating corresponding sensor data; deriving a statistical sensor (SS) value based on the sensor data; deriving a statistical position error signal (SPES) value from servo sectors read by the head; comparing the SS value to a SS-threshold value; comparing SPES value to a SPES-threshold value; and generating a feed-forward command effort signal for reducing rotational vibration effects if the SS value exceeds the SS-threshold value and if SPES value exceeds the SPES-threshold value.

US Patent:

6952318, Oct 4, 2005

Filed:

Jan 30, 2004

Appl. No.:

10/769444

Inventors:

Lan V. Ngo - Garden Grove CA, US

Assignee:

Western Digital Technologies, Inc. - Lake Forest

International Classification:

G11B019/02

US Classification:

360 69

Abstract:

A method for reducing the effects of rotational vibration in a disk drive comprising generating a self-induced vibration in the disk drive, and sensing the self-induced vibration in the first and second sensors and generating a corresponding first and second sensor data. The method further comprises comparing the first and second sensor data to determine a gain-differential, and scaling at least one of the first and second sensor data to reduce the gain-differential between the first and second sensors.