Patent ID: 7023767
Filing Date: 2006-04-04
Classification: G11B

Abstract:
1. A gain calibration method for DPP (differential push-pull) tracking error signals in an optical storage system for correcting a ratio of an amplifier gain of a sub beam to an amplifier gain of a main beam, the gain calibration method comprising the steps of: powering on a laser light source and focusing laser beams; enabling a spindle motor; controlling a first state of an objective lens relative to a disc; measuring an eigenvalue of the push-pull signal of the main beam, with respect to an objective lens-shift, as a first main beam eigenvalue; measuring an eigenvalue of the push-pull signal of the sub beam, with respect to the objective lens-shift, as a first sub beam eigenvalue; controlling a second state of the objective lens relative to the disc; measuring an eigenvalue of the push-pull signal of the main beam, with respect to an objective lens-shift, as a second main beam eigenvalue; measuring an eigenvalue of the push-pull signal of the sub beam, with respect to the objective lens-shift, as a second sub beam eigenvalue; and computing the gain ratio of the sub beam to the main beam according to the first main beam eigenvalue, first sub beam eigenvalue, second main beam eigenvalue, and second sub beam eigenvalue.