| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical disk unit capable of correctly discriminating a recorded/unrecorded region even when noise is on a reproduction RF signal. SOLUTION: The optical disk unit is provided with a comparator circuit 6 which discriminates a recorded/unrecorded region on an optical disk by comparing a level difference between the peak level of the RF signal and a bottom level which are obtained by playing back the optical disk with a threshold value, a recorded/unrecorded threshold value setting circuit 8 which outputs the threshold value used by the comparator circuit 6 for judging the recorded/ unrecorded region, a threshold value correction setting circuit 7 which detects a deviation caused by the noise of the RF signal from the peak level and the bottom level of the RF signal obtained while playing back the unrecorded region of the optical disk and outputs an amount of correction to the threshold value, and an adder circuit 9 which adds the threshold value and the amount of correction to set an adding result to the comparator circuit 6 as a threshold value to be used for judging the recorded/unrecorded region. |
