| 摘要 |
<p>PROBLEM TO BE SOLVED: To detect writing of a pick-up data considering a noise level by determining a provisional threshold level based on a magnetic reading output in a magnetic recording layer where the pick-up data cannot be recorded. SOLUTION: A noise level is obtained from an output of magnetic reading in an area of a magnetic recording layer where pick-up data cannot be recorded, and a provisional reading threshold level is calculated based on the noise level (S107). The difference between the maximum and minimum levels of the magnetic reading output in a magnetic recording layer where the pick-up data are recorded is obtained, and writing of the pick-up data is detected when it is judged prescribed times successively that the level difference is larger than the provisional reading threshold level (S114). From the magnetic reading output in the area of the magnetic recording layer where the pick-up data are recorded and the noise level, a reading threshold level is calculated only when the difference between the two is a certain reference value or larger, and the provisional reading threshold level is altered.</p> |
