| 摘要 |
PURPOSE:To accurately detect the abnormality of focus servo in a short time by reading data pre-formatted on a recording medium, and judging a case where the data is impossible to be discriminated within a prescribed time as the abnormality of the focus servo. CONSTITUTION:An SMD signal reproduced by a head in a recording are reproducing mechanism 16 is read, and the value SMD1 is stored in a RAM15. Next, a timer with a time (t) to detect the abnormality of the focus servo is started, and the SMD signal is read again, and the value SMD2 is stored in the RAM15, then, the values SMD1 is compared with the SMD2. Thus, the data pre-formatted on the recording medium is read, and the case where the data is impossible to be discriminated within the prescribed time is judged as the abnormality of the focus servo. In such a way, it is possible to detect the abnormality of the focus servo in a short time and accurately in spite of the eccentricity of the recording medium or the ON/OFF of tracking servo. |
