Method and apparatus for disc rotation control in an optical storage system based on detected extent of disc warping

摘要

An apparatus is provided for disc rotation control in an optical storage system, which is capable of generating a focusing error signal from light that was reflected by a loaded optical disc. The apparatus includes a focus controller for processing the focusing error signal to obtain a focus output signal, a low pass filter unit for processing the focus output signal by low pass filtering to obtain a filtered signal, a direct current level remover for removing a direct current component of the filtered signal to obtain a warp-indicating signal, and a speed controller for comparing the warp-indicating signal with a predetermined threshold value to determine extent of warping of the optical disc. The speed controller is operable to control the optical storage system so as to limit maximum rotation speed of the optical disc according to result of the comparison made by the speed controller.