Patent ID: 8130615
Filing Date: 2012-03-06
Classification: G11B

Abstract:
1. A track-crossing signal generator for use in an optical disc drive, comprising: a bottom envelope detecting unit for receiving a radio frequency signal, and outputting a bottom envelope signal; a defect detector electrically connected to the bottom envelope detecting unit for receiving the bottom envelope signal, and generating a defect signal when a defect area is formed on a disc track; an auto gain control unit electrically connected to the bottom envelope detecting unit for receiving the bottom envelope signal and dynamically adjusting a gain value according to an amplitude of the bottom envelope signal; an amplifier electrically connected to the bottom envelope detecting unit and the auto gain control unit for receiving the bottom envelope signal; and a bias tracking unit electrically connected to the defect detector and the amplifier for generating a bias to the amplifier according to the radio frequency signal or the bottom envelope signal and a reference level; wherein the amplifier subtracts the bias from the bottom envelope signal and dynamically adjusts the bottom envelope signal according to the gain value when the bias is received by the amplifier, thereby amplifying the bottom envelope signal and outputting the amplified bottom envelope signal as a track-crossing signal.