Disk drive to characterize misaligned servo wedges

In a disk drive including an actuator arm and a head connected to a distal end of the actuator arm, the actuator arm being rotatable about a pivot to move the head radially over a disk, the disk having a plurality of tracks in which a substantial majority of the tracks include a plurality of servo wedges spaced sequentially around a circumference of the track for use in track following, a method to characterize misaligned servo wedges comprising:

• commanding the head to track follow on a track;
• measuring wedge to wedge time (WTWT) values corresponding to time intervals between identified servo wedges;
• calculating wedge to wedge time (WTWT) variations for the measured WTWT values;
• and
• characterizing the calculated WTWT variations, wherein characterizing the calculated WTWT variations for the track includes utilizing a WTWT variation modeling function to model the WTWT variations.

A disk drive to characterize misaligned servo wedges comprising:

• means for moving a head radially over a disk having a plurality of tracks, a substantial majority of the tracks including a plurality of servo wedges spaced sequentially around a circumference of the track for use in track following;
• means for commanding the head to track follow on a track;
• means for measuring wedge to wedge time (WTWT) values corresponding to time intervals between identified servo wedges;
• means for calculating wedge to wedge time (WTWT) variations for the measured WTWT values;
• and
• means for characterizing the calculated WTWT variations, wherein the means for characterizing the calculated WTWT variations for the track includes utilizing a WTWT variation modeling function to model the WTWT variations.