Patent ID: 6950273
Filing Date: 2005-09-27
Classification: G11B

Abstract:
1. A magnetic disk drive comprising: position error signal calculating means for calculating, according to information reproduced from said magnetic head, a position error signal as a difference between a position signal and a target position of said magnetic head, said position signal showing relative position data of said magnetic head to record or reproduce information to or from a magnetic disk with respect to position information previously recorded on said magnetic disk; control input calculating means for calculating a control input based on said position error signal; positioning control means for positioning said magnetic head to a target position according to said control input; filtering process means for filtering said position error signal; and synchronous vibration learned value calculating means for averaging a filtered position error signal, and calculating, as a synchronous vibration learned value, a synchronous vibration estimate representing an estimate of a synchronous vibration component synchronous with the rotation of said magnetic disk, based on said signal averaged.