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

摘要

A digital signal processing device 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 an optical disc loaded in the optical storage system. The digital signal processing device includes a low pass filter for removing a high-frequency component of the focusing error signal 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 controller for comparing the warp-indicating signal with a predetermined threshold value to determine extent of warping of the optical disc. The controller functions 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 controller.