Embodiments of the present invention provide a data recording device
capable of achieving desired performance while increasing the convergence
rate. According to one embodiment, in a data recording device, an
update-width determination unit included in a setting updating unit
determines an update-width of a set frequency f in a digital filter
according to the size of a position error signal PES, and an update-width
adjuster included in the setting updating unit changes the update-width
of the set frequency f determined by the update-width determination unit
according to the size of the set frequency f. Thus, while the convergence
rate being kept properly, the set frequency f can precisely be converged
on a frequency of a disturbance component.