Morrison & Foerster LLP
Method for measuring PES noise of servo patterned media
A method for measuring servo pattern irregularity and other servo information of pre-patterned servo media mounted on a spindle with the center of the pre-pattern tracks off center from the axis rotation of the spindle. An actuator is stepped radially while measuring the PES signals from the servo sectors of at least one highly eccentric track to form a cross track profile of the PES signals for each sector. A mathematical algorithm removes step measurement error from the data. A second mathematical algorithm removes non-repeatable random noise from the data. The amount of phase-in that radially aligns the respective cross track profiles is computed. Servo pattern written-in repeatable runout is determined by unwrapping the phase-in values to form a periodic curve.
Seagate Technology LLC
G G
G11B G11B
inventional inventional
Koichi Xinwei David Shiao-Min
Wago Li Kuo