Patent ID: 6049513
Filing Date: 2000-04-11
Classification: G11B

Abstract:
A method for adjusting a focus bias in an optical disc player, said method comprising the steps of:(a) reading out data recorded on an optical disc to generate an RF signal corresponding to a reproduction signal and generating a focus servo control signal;(b) detecting a focus error signal while inputting the focus servo control signal generated in step (a), and generating a focus control signal in response to a detected focus error signal;(c) setting a plurality of focus biases of different signal levels and generating a focus bias having a predetermined signal level;(d) equalizing a waveform of the RF signal generated in step (a) and generating a waveform-equalized RF signal;(e) converting the waveform-equalized RF signal generated in step (d) into a train of pulses and generating a pulse train signal;(f) detecting a pulse corresponding to a synchronizing signal among the pulse train signal generated in step (e) and generating a detected synchronizing signal;(g) holding a peak value of the synchronizing signal detected in step (f) and generating a held peak signal;(h) detecting leading edges of the synchronizing signal detected in step (f) and generating a leading edge detection signal corresponding to a train of pulses in response to detected leading edges;(i) delaying the held peak signal generated in step (g) for a predetermined time interval and generating a delayed peak hold signal in response to a first leading edge detection signal generated in step (h) until a second leading edge detection signal provided just after the first leading edge detection signal is applied;(j) comparing the peak hold signal delayed in step (i) with the peak signal held in step (g) and generating a comparison signal; and(k) adjusting the focus bias generated in step (c) in order for a magnitude of the peak signal held in step (g) to be greater than a magnitude of the peak hold signal delayed in step (i).