Patent ID: 7522480

Claim:
A method of multi-track seeking to move an optical pick up unit to a desired track, comprising: receiving, at a digital signal processor, digitized optical signals from the optical pick-up unit; within the digital signal processor, selecting whether to calculate a focus error signal or a tacking error signal from the digitized optical signals; calculating a current track crossing velocity from a derivative of the tracking error signal; calculating the number of tracks that must be crossed by the optical pick up unit to reach the desired track; calculating a reference track crossing velocity from the number of tracks that must be crossed; calculating a velocity error based upon the difference between the reference track crossing velocity and the current track crossing velocity; clamping the velocity error to a predetermined value if the velocity error exceeds the predetermined value; accelerating the optical pick up unit to the reference track crossing velocity based upon the velocity error, the acceleration being clamped according to the clamping of the velocity error; after the optical pick up unit has reached the reference track crossing velocity, maintaining the optical pick up unit at the reference track crossing velocity based upon the velocity error until the vicinity of the desired track has been reached; and when the optical pick up unit has reached the vicinity of the desired track, deacclerating the optical pick up unit to reach the desired track.