Patent ID: 6259664
Filing Date: 2001-07-10
Classification: G11B

Abstract:
A defect detection circuit in an optical disc data reproduction system including an optical pick up unit for generating an analog RF signal, the defect detection circuit for detecting defects in the RF signal comprising:a comparator for comparing the RF signal voltage level with a first compare voltage having a predetermined voltage level and with a second compare voltage having a predetermined voltage level lower than the first compare voltage, and in response to the RF signal voltage level being greater than that of the first compare voltage generating a first comparison signal, and in response to the RF signal voltage level being less than that of the second compare voltage generating a second comparison signal; anda defect detector for receiving the first and second comparison signals and a channel bit clock signal, and for generating a defect detecting signal when both the first and second comparison signals are deactivated for a time period that is greater in length than a first time duration and when the first or the second comparison signal is deactivated for a time period that is greater in length than a second time duration.