DEFECT DETECTING DEVICE, OPTICAL DISK DEVICE, AND DEFECT DETECTING METHOD

摘要

PROBLEM TO BE SOLVED: To improve detection accuracy of defect in which attenuation quantity of signal amplitude due to an attached finger print or the like is comparatively small and an amplitude level in a defective area is varied. SOLUTION: A defect detecting device 1 compares a bottom hold signal S2 obtained by detecting a bottom level of a peak hold signal S1 in which a peak level of an input RF signal is detected with a voltage threshold value Vth in a comparing circuit 12, and outputs a defect detection signal. Also attenuation properties of a high speed peak hold circuit 10 generating the signal S1 and a low speed bottom hold circuit generating the signal S2 are decided so that attenuation speed of a signal level of the bottom hold signal S2 is made smaller than attenuation speed of a signal level of the peak hold signal S1. COPYRIGHT: (C)2007,JPO&INPIT