Abstract: A method for enhancing the optical initializing operation comprises: sending a radial error signal from an optical pick-up unit to a radial error signal calibration unit; sending the radial error signal from the optical pick-up unit to an offset adjuster; sending a calibrated radial error signal from the radial error signal calibration unit to the offset adjuster and a gain adjuster; sending a radial actuator (RA) signal from the radial error signal calibration unit to activate a radial actuator during an initialization or a period for calculating RE signal calibrating parameters.

Abstract: A signal-processing device (301) for controlling a focus actuator (309) in an optical disc system (30), wherein the signal processing device (309) generates a focus actuator control signal (CS) to be supplied to the focus actuator (309). The focus actuator control signal (CS) is based on a focus error signal (FE) and a central aperture signal (CA). If the central aperture signal (CA) is equal to or above a certain threshold value the focus actuator control signal will correspond to the focus error signal (FE). However, when the central aperture signal is below the threshold value the focus actuator control signal will have a predefined level. By providing a focus actuator control signal (CS) in accordance herewith it is possible to extend the regions of the focus error signal (FE) in which the relative distance between the focus point and the data layer of the record medium (304) is not correctly represented.

Abstract: A method of determining a size of an optical disc inserted into an optical disc drive is disclosed. The method includes driving a turntable motor of the optical disc drive to rotate the optical disc at a predetermined rotation frequency for reading data stored on the optical disc, measuring a rotation frequency of the turntable motor, applying a kick-pulse voltage to the turntable motor of the optical disc drive for a predetermined period of time, measuring a change in the rotation frequency of the turntable motor after applying the kick-pulse voltage, comparing the change in the rotation frequency of the turntable motor to a threshold value, and determining that the optical disc is an 8 cm disc when the change in the rotation frequency of the turntable motor is above the threshold value.

Abstract: A method for enhancing the optical initializing operation comprises: sending a radial error signal from an optical pick-up unit to a radial error signal calibration unit; sending the radial error signal from the optical pick-up unit to an offset adjuster; sending a calibrated radial error signal from the radial error signal calibration unit to the offset adjuster and a gain adjuster; sending a radial actuator (RA) signal from the radial error signal calibration unit to activate a radial actuator during an initialization or a period for calculating RE signal calibrating parameters.

Abstract: A method of determining a size of an optical disc inserted into an optical disc drive is disclosed. The method includes driving a turntable motor of the optical disc drive to rotate the optical disc at a predetermined rotation frequency for reading data stored on the optical disc, measuring a rotation frequency of the turntable motor, applying a kick-pulse voltage to the turntable motor of the optical disc drive for a predetermined period of time, measuring a change in the rotation frequency of the turntable motor after applying the kick-pulse voltage, comparing the change in the rotation frequency of the turntable motor to a threshold value, and determining that the optical disc is an 8 cm disc when the change in the rotation frequency of the turntable motor is above the threshold value.

Abstract: A signal-processing device (301) for controlling a focus actuator (309) in an optical disc system (30), wherein the signal processing device (309) generates a focus actuator control signal (CS) to be supplied to the focus actuator (309). The focus actuator control signal (CS) is based on a focus error signal (FE) and a central aperture signal (CA). If the central aperture signal (CA) is equal to or above a certain threshold value the focus actuator control signal will correspond to the focus error signal (FE). However, when the central aperture signal is below the threshold value the focus actuator control signal will have a predefined level. By providing a focus actuator control signal (CS) in accordance herewith it is possible to extend the regions of the focus error signal (FE) in which the relative distance between the focus point and the data layer of the record medium (304) is not correctly represented.

Abstract: In a scanning apparatus, a scanning spot is moved along a path from one track to another track of the information carrier, the scanning spot is accelerated in a first stage of the movement and decelerating in a second stage of the movement. Initially during the movement a displacement of the scanning spot is derived from a first and a second position signal. The velocity of the scanning spot is estimated during movement along the path. After the estimated velocity of the scanning spot exceeds a first predetermined value during the first stage of the movement, the displacement of the scanning spot is derived from the first position signal and independent from the second position signal, during movement along the path. After the estimated velocity has decreased below a second predetermined value during the second stage of the movement, the displacement of the scanning spot is again derived from both the first and the second position signal, during movement along the path.

Abstract: A device according to the invention is suitable for scanning an information carrier with tracks around an axis. The device has means for transferring information to/from a scanning spot on the information carrier. The device has tangential displacement means for moving the scanning spot in a tangential direction and radial displacement means for moving the scanning spot in a radial direction. The device has control means for controlling the radial displacement means and radial position measurement means for generating a radial position signal (cos(9&bgr;r), sin(9&bgr;r)) which is a measure of the instantaneous radial position of the scanning spot. The device has a scanning mode in which the scanning spot follows a track and a displacement mode in which tracks are crossed. The device according to the invention is characterized by tangential position detection means for generating a tangential position signal (S&agr;) which is indicative of the tangential position (&agr;) of the scanning spot.