Patent ID: 6414812
Filing Date: 2002-07-02
Classification: G11B

Abstract:
A medium replacement type disc apparatus comprising:a spindle for rotating a disc; a head facing a track on the disc; a frequency rectification filter constituted by a sinusoidal wave model increasing a gain of a particular frequency component of a position error signal produced by the head; a phase compensation filter for generating a control input for the head to follow the track according to the output of the frequency rectification filter; a power amplifier for amplifying an output of the phase compensation filter; an actuator for moving the head with respect to the disc in its radial direction according to a drive signal amplified by the power amplifier; a main controller for performing drive control of the spindle and seek control of the head by the actuator according to an external access instruction; and a memory used for processing by this main controller, wherein the main controller has a rotation angle detection function for detecting a rotation angle of the spindle, and before reducing rotation speed of the spindle, stores in the memory the state amount of the frequency rectification filter together with the rotation angle of the spindle at that moment, and accelerates the spindle and, after the spindle speed has reached a predetermined constant speed, monitors the rotation angle of the spindle, and when the spindle rotation angle becomes equal to the rotation angle stored in the memory, sets in the frequency rectification filter the state amount of the frequency rectification filter stored in the memory.