HIGH FREQUENCY CENTRAL APERTURE TRACKING

摘要

The present invention relates to an optical system for performing radial tracking on an associated optical record carrier. The optical system contains at least one radiation-emitting device capable of emitting at least three beams: a first beam for reading and/or recording information, and at least a second beam and a third beam for tracking. The optical system is adapted for radial tracking of the first spot from a tracking error signal generated based on the high-frequency component of the central-aperture signal of the second and third beams. The tracking error signal may be generated based on a difference signal of a DC-level of the power of the high-frequency components of the central-aperture signal.