A method for dynamic in-situ characterization of in-plane and out-plane thermal
drift of a hard disk drive head suspension is provided. A first data track is written.
Amplitude and amplitude modulation of the write data signal are measured and track
center is determined. Data tracks are then written for a selected time period.
Amplitude and amplitude modulation of the write data signal is measured and a new
track center of a last data track is determined. Any difference between the track
center of the first data track and the track center of the last data track represents
in-plane drift. The amplitude and amplitude modulation of the two write data signals
is compared and any difference between the measured values is proportional to out-plane drift.
