Patent ID: 6222336
Filing Date: 2001-04-24
Classification: G11B

Abstract:
A method for detecting application of rotational vibration to a disc drive having a spindle motor with a driver coil and a driver magnet, the spindle motor rotating a data storage disc through controlled application of current to the driver coil to establish a magnetic field which interacts with a magnetic field generated by the permanent magnet, the method comprising steps of:(a) immersing a velocity sense coil in a magnetic field generated by a permanent magnet of the spindle motor;(b) generating a motor velocity signal indicative of a rotational velocity of the disc in relation to a voltage induced across the velocity sense coil by relative movement between the velocity sense coil and the magnetic field of the immersing step (a); and(c) detecting application of rotational vibration to the disc drive in relation to the motor velocity signal.