An apparatus and method are provided for quickly and finely compensating
for non-repeatable run out (NPRO) of a disc drive. The NPRO compensation
control apparatus in a run out compensation apparatus of a system
includes: a frequency estimator directly estimating a trigonometric
function value of an NRRO frequency from a predetermined signal
responding to the system using a correlation between a filter coefficient
of a notch filter and a notch frequency; and an NRRO compensator
canceling NRRO of the system using the trigonometric function value of
the NRRO frequency estimated by the frequency estimator.