Abstract: The present disclosure describes techniques for DVD-RAM header or land/groove detection. In some aspects, a wobble signal is integrated, an offset is removed from the integrated wobble signal, and a header is detected in the non-offset integrated wobble signal. In some aspects, a threshold value is adjusted based on a comparison of the received wobble signal and the threshold value, and a header is detected based on the adjusted threshold value.

Abstract: An optical disk drive and a method for scanning an optical disk that includes a substantially circular track with a scanning velocity is provided. A servo control signal (SCS) is determined based on a servo error signal (SES). A first performance indicator (IND1) of the servo actuator is determined from at least one of the SES and SCS. IND1 is compared against a first pre-determined threshold (ITHR1), determining a first servo margin (MAR1). The scanning velocity is set in dependence on at least MAR1. In particular, scanning velocity is reduced when the first performance indicator exceeds the first pre-determined threshold. Additionally or alternatively, a bandwidth of control of the servo actuator can be adjusted in dependence on at least one of a second servo margin, determined from at least one of SES and SCS, and a third servo margin, associated with a mark quality determined from a central aperture signal.

Abstract: In a tracking control method for use in an optical disk drive to read/write an optical disk, an open-loop tracking control operation of the optical disk drive is first performed according to an input tracking error signal and a predetermined periodical offset to generate a dynamic offset. Afterwards, a closed-loop tracking control operation of the optical disk drive is performed according to the input tracking error signal calibrated with the dynamic offset.

Abstract: An optical disk drive and a method for scanning an optical disk that includes a substantially circular track with a scanning velocity is provided. A servo control signal (SCS) is determined based on a servo error signal (SES). A first performance indicator (IND1) of the servo actuator is determined from at least one of the SES and SCS. IND1 is compared against a first pre-determined threshold (ITHR1), determining a first servo margin (MAR1). The scanning velocity is set in dependence on at least MAR1. In particular, scanning velocity is reduced when the first performance indicator exceeds the first pre-determined threshold. Additionally or alternatively, a bandwidth of control of the servo actuator can be adjusted in dependence on at least one of a second servo margin, determined from at least one of SES and SCS, and a third servo margin, associated with a mark quality determined from a central aperture signal.

Abstract: In a tracking control method for use in an optical disk drive to read/write an optical disk, an open-loop tracking control operation of the optical disk drive is first performed according to an input tracking error signal and a predetermined periodical offset to generate a dynamic offset. Afterwards, a closed-loop tracking control operation of the optical disk drive is performed according to the input tracking error signal calibrated with the dynamic offset.