Patent ID: 6433952
Filing Date: 2002-08-13
Classification: G11B

Abstract:
Method for tracking control of a head unit with respect to data tracks on a data medium, which data tracks are arranged essentially parallel to the movement direction of the data medium relative to the head unit, wherein the data tracks are divided into successive data sections, which are each subdivided into an initial region and a useful region, wherein the method comprises the following steps:a) determining primary measured values from a first control track extending within the initial region and the useful region while a data section is moving past the head unit; b) determining secondary measured values from a second control track extending within the initial region while the initial region of a data section is moving past the head unit; c) determining a first tracking signal from the primary measured values; d) determining a second tracking signal from both the primary measured values and the secondary measured values, e) generating a difference signal based on the comparison of the first and the second tracking signal; f) storing the difference signal; g) generating a tracking control signal from the second tracking signal while the initial region is moving past the head unit; and h) generating a tracking control signal from the first tracking signal and the stored difference signal while the data region is moving past the head unit.