Patent ID: 8432774
Filing Date: 2013-04-30
Classification: G11B

Abstract:
1. A tracking servo for driving an optical head to move with respect to an optical disc, the optical head emitting lights for reading data from or writing data to the optical disc, the optical disc comprising a plurality of tracks, the tracking servo comprising: a storing unit storing a table for listing a plurality of track classes and tracking errors associating with the corresponding track classes, the plurality of track classes are defined based on track amount; a counting unit counting the number of tracks between a current track in which the optical head is currently positioned and a target track from or to which the optical head reads or writes data; a first determining unit determining whether the number of the tracks between the current track and the target track reaches a predetermined value; a long tracking unit calculating first jumping tracks when the number of the tracks between the current track and the target track reaches the predetermined value; and a searching unit searching the table for the tracking error associating with one of the track classes which corresponds to the number of the tracks between the current track and the target track; wherein the long tracking unit calculates second jumping tracks based on the first jumping tracks and the found tracking errors, and drives the optical head to move to the second jumping tracks for tracking.