Method and apparatus for judging blank area and data recorded-area of optical disc

摘要

An apparatus for judging an optical disc includes a gain controller, an amplitude detecting unit and an amplitude comparing unit. The gain controller is used for receiving a radio frequency signal from an optical pickup head; and processing the radio frequency signal into an amplified radio frequency signal with a target amplitude according to an amplitude feedback signal. The amplitude detecting unit is used for receiving the amplified radio frequency signal, generating the amplitude feedback signal to the gain controller, and outputting a top envelope amplitude according to an top envelope signal of the amplified radio frequency signal. The amplitude comparing unit is used for comparing the top envelope amplitude with a threshold value to generate a resulting signal, and judging whether the laser beams emitted from the optical pickup head are irradiated on a blank area or a data-recorded area according to the resulting signal.