Tracking and focus servo system with automatic media type detector
View Patent ↗A media type detector in a tracking and focus servo system is presented. Operating parameters for a first media type are loaded and a peak-to-peak value of a tracking error signal is calculated. Whether the media type is the first media or a second media can then be determined by comparing the peak-to-peak value with a threshold value.
1. An optical disk drive, comprising:
an optical pick-up unit;
an analog processor coupled to receive signals from detectors in the optical pick-up unit and provide digital signals;
at least one processor coupled to receive the digital signals, the at least one processor calculating a control signal; and
a driver coupled to control a position of the optical pick-up unit in response to the control signal,
wherein the at least one processor executes an algorithm that
loads operating parameters of the optical disk drive appropriate for a first media type of an optical media,
calculates a tracking error signal from the digital signals with a tracking servo system open,
calculates a peak-to-peak value of the tracking error signal,
compares the peak-to-peak value with a threshold value to determine a media type of the optical media, and
loads operating parameters of the optical disk appropriate for a second media type if the media type is determined to be the second media type.
2. The drive of claim 1 , wherein the at least one processor positions the optical pick-up of the optical disk drive over an area of an optical media with tracks.
3. The drive of claim 1 , wherein the operating parameters includes at least one parameter from the set consisting of a focus error signal gain, a focus error signal offset, a focus loop gain, a tracking error signal gain, a tracking error signal offset, a tracking loop gain, and a cross-talk parameter.
4. The drive of claim 1 , wherein the first media is a writeable media.
5. The drive of claim 4 , wherein the media type is determined to be writeable if the peak-to-peak value exceeds the threshold value and determined to be premastered if the peak-to-peak value is less than the threshold value.
6. The drive of claim 5 , wherein the threshold value is greater than half an expected peak-to-peak value for writeable media and less than the expected peak-to-peak value.