METHOD FOR GENERATING STABLE FOCUS OK SIGNAL

摘要

PURPOSE: A method for generating a stable focus OK signal is provided. CONSTITUTION: A method for generating a stable OK signal comprises a step(S1) for outputting an RF amplification signal by adding a beam signal; a step(S2) for receiving the RF amplification signal, and outputting its upper limit envelop signal; a step(S3) for receiving the RF amplification signal, and outputting its lower limit envelop signal; a step(S4) for outputting an addition signal by adding the upper and lower limit envelop signals; a step for(S5) generating a focus error signal from the beam signal; a step(S6) for detecting a maximum value of the focus error signal; a step(S7) for detecting a zero cross time of the focus error signal; a step(S8) for passing the addition signal by connecting a switch at the zero cross time detection point; a step(S9) for comparing the addition signal with a predetermined slide voltage according to a size of the disc; a step(S10) for outputting a high potential level focus OK signal when the addition signal is greater than the slide voltage; and a step(S11) for outputting a low potential level focus OK signal when the addition signal is smaller than the slide voltage.