Track-following method in optical disc apparatus and optical disc apparatus adopting this method

摘要

In a track-following method in a DVD-RAM disc, CAPA detection is avoided during the track-following process, and a track-following operation is stably made from a high-speed state using adaptive deceleration pulses. In order to avoid CAPA detection during the track-following process, a CAPA is detected from a tracking error signal using a high-pass filter, and the track-following start timing is set within 0.4 ms after the detection of the CAPA. The pulse width of the adaptive deceleration pulses to a lens actuator is variable so that the tracking error signal follows a standard tracking error signal. The zero-crossing point of the tracking error signal after the detection of the CAPA is set as the track-following start timing, and tracking-servo is started after an adaptive brake process for varying the deceleration pulse width based on the difference between the tracking error signal and standard tracking error (TE) signal.