Patent ID: 7266076

Claim:
A land pre-pits signal level automatic detecting device, which employs a digital processor to recognize the practical position of the land pre-pits (LPP) signal, employing a automatic slice level, which is composed by level automatic detection of the RC circuit and a fixed slice level, as the basis for detecting the land pre-pits, the device comprising: a bottom signal generator, which is coupled to an optical pickup circuit, for receiving a land pre-pits (LPP) signal and a land pre-pits window to generate a land pre-pits bottom hold signal; a sample signal generator, which is coupled to the bottom signal generator, for receiving the LPP bottom signal and a sample and hold signal to generate a hold level signal; an analog computer, which is coupled to the sample signal generator, for receiving the hold level signal and a fixed slice level to generate a sliced level signal after analog addition; a comparator, which is coupled to the analog computer and the optical pickup circuit, for receiving the LPP signal and the sliced level signal thereby generating a LPP sliced signal; and a digital processor, which is coupled to the comparator, for receiving the LPP sliced signal and a wobble clock to generate the LPP window and the sample and hold signal.