Patent ID: 7729214
Filing Date: 2010-06-01
Classification: G11B

Abstract:
1. An apparatus in an optical disc drive for obtaining a push-pull signal according to a first fluctuating signal and a second fluctuating signal, the first fluctuating signal being generated according to detecting signals generated from one side of a photo detector, the second fluctuating signal being generated according to detecting signals generated from the other side of the photo detector, the apparatus comprising: a first amplifier coupled to the first fluctuating signal for utilizing a first gain value to amplify the first fluctuating signal and then outputting a first amplified fluctuating signal; a second amplifier coupled to the second fluctuating signal for utilizing a second gain value to amplify the second fluctuating signal and then outputting a second amplified fluctuating signal; a subtractor electrically connected to the first and second amplifiers for subtracting the second amplified fluctuating signal from the first amplified fluctuating signal to generate the push-pull signal; and a level decision unit electrically connected to the first and second amplifiers for adjusting amplitudes of signals amplified by the first and second amplifiers; wherein when the optical disk drive is switched from a read or write mode to a blank mode, the level decision unit adjusts the amplitudes of the signals amplified by the first and second amplifiers to be lower.