Patent ID: 8159917

Claim:
A wobble detector for an optical disk drive, the wobble detector comprising: an operational amplifier configured to receive first and second signals comprising position information of data on an optical disk, sum the received first and second signals to generate a summed signal, and amplify the summed signal based on an amplification control signal to generate an output signal; a buffer configured to buffer the output signal and output a result of the buffering as first and second differential signals, wherein a first output of the buffer outputs the first differential signal and a second output of the buffer outputs the second differential signal, wherein the first and second outputs of the buffer are distinct from one another; an automatic gain amplifier configured to perform an automatic gain amplification on the first and second differential signals to output a single ended signal; a level shifter configured to shift a level of the single ended signal including an offset voltage and output a level shifted signal as first and second level shifted differential signals by increasing a voltage level of the first differential signal by the offset voltage and decreasing a voltage level of the second differential signal by the offset voltage; an A/D converter configured to A/D convert a difference between the first and second level shifted differential signals to output a digital signal; and a controller configured to detect the offset voltage based on the digital signal and output the amplification control signal to the operational amplifier in response to the detected offset voltage.