| 摘要 |
PURPOSE:To substantially dissolve a defect even if the defect due to a defect of a face plate exists in servo information written on a disk type recording medium, by modulating the write time width of servo information to be written on the detected defective position and writing it again. CONSTITUTION:If the read waveform amplification level in a certain position on the disk type recording medium where servo information is written with a time width Tc is not satisfactory because of the presence of defects of the face plate in accordance with the characteristic of waveform amplification level V of read servo information corresponding to write time width T of servo information, the time width is modulated to Tc+DELTAT only in this position to rewrite servo information. Thus, the read waveform amplitude level in this position is increased to reach a reference level Vp regardless of existence of the defect of the face plate. If the read waveform amplitude level is excessive, the time width is modulated to Tc-DELTAT to rewrite servo information. Thus, the read waveform amplitude level coincides with the reference level similarly. |
