Patent ID: 8009525
Filing Date: 2011-08-30
Classification: G11B

Abstract:
1. An optical disc signal processing device comprising: a drive means which changes the physical position or angle of an optical pickup; an error detection means which detects the physical positional relation between the optical pickup and a recording medium from an electric signal generated by the optical pickup; a control target value change means which changes a control target value in the optical disc signal processing device; a control means which controls the drive means according to the outputs from the error detection means and the control target value change means; an adjustment reference signal generation means which generates an adjustment reference signal for adjusting the control target value; a control target value adjustment means which adjusts the control target value changed by the control target value change means, on the basis of the output from the adjustment reference signal generation means; a margin measurement means which obtains a range of the control target value from its minimum value to its maximum value, said control target value being changed by the control target value change means, within which range the optical disc signal processing device can perform normal operation; a condition setting means which sets a threshold value of the adjustment reference signal when measuring the range using the margin measurement means; a utilization rate measurement means which measures the utilization rate of the optical disc signal processing device; a nonvolatile memory which stores the range of the control target value from its minimum value to its maximum value, which is obtained by the margin measurement means, together with the utilization rate outputted from the utilization rate measurement means; a comparison means which compares the range of the control target value from its minimum value to its maximum value, which is stored in the nonvolatile memory, with the control target value which is adjusted by the control target value adjustment means; and an adjustment method switching means which changes the change amount of the control target value to be changed by the control target value change means, on the basis of the number of measurements for the adjustment reference signal that is used for adjusting the control target value by the control target value adjustment means or the output from the control target value adjustment means, and switches the control target value adjustment method according to the output from the comparison means; wherein the adjustment method of the control target value adjustment means, or the number of measurements for the adjustment reference signal, or the change amount of the control target value is optimized so that the control target value to be adjusted by the control target value adjustment means is included in the range of the control target value from its minimum value to its maximum value, which range is obtained by the margin measurement means and stored in the nonvolatile memory.