| 摘要 |
PURPOSE: To accurately recognize a positioning address without diverging or omitting a binary pulse even when servo signal waveforms of outer and inner peripheral sides are different, or even when excess peak waveform exists mixedly by the use of a thin film head, in the case of reading servo data recorded in the writing period of a predetermined frequency. CONSTITUTION: The filter characteristics of a characteristic variable type low- pass filter 23 are variably set to a low cut-off frequency fc and a small boosting amount at the outer peripheral zone based on table data stored previously in an EEPROM 27 or a high cut-off frequency and a large boosting amount on the high band side at the inner peripheral zone, thereby making servo signal waveforms on the outer and inner peripheral sides uniform. Further, a threshold level (x) at a binarizer 24 is variably set to be higher on the outer peripheral side or lower on the inner peripheral side. |
