Patent ID: 7301863

Claim:
A method for canceling a land-groove offset component of a focusing error signal in an optical storage system, the optical storage system including an optical pickup for providing the focusing error signal, a radio (or wobble) frequency ripple signal, and a tracking error signal, and a focusing device responsive to the focusing error signal for focusing a light spot in position on an optical disc, said method comprising the steps of: a) processing the radio (or wobble) frequency ripple signal to obtain a first processed signal that is multiplied by a first gain value (G 1 ) so as to result in a first signal; b) processing the tracking error signal to obtain a second processed signal that is multiplied by a second gain value (G 2 ) so as to result in a second signal; c) adding the first and second signals to produce a compensative land-groove offset component; and d) feeding the compensative land-groove offset component into the focusing device to enable the focusing device to cancel out the land-groove offset component of the focusing error signal.