| 摘要 |
PURPOSE:To measure an off-track amount in one rotation of a disk due to eccentricity of a disk device, as well, by setting a relative level ratio of each adjacent data block as an off-track amount, when a read-out head of the disk device reproduces a data block in a prescribed track of the disk. CONSTITUTION:Data blocks which are recorded alternately and at almost equal intervals, respectively, in the inside circumferential and the outside circumferential directions of a disk beginning with a base point (index signal position) 12 of a track by setting a locus 11 of a sensor position of the track (head width) in a prescribed track as a boundary are provided like O1, E1, O2, E2...On, En extending over one round of the track. The more the number of these data blocks on one round of the track becomes, the more the resolution is improved, but a value which does not become a problem in practical use is >=10, and actually the number is set to about 100 blocks as a range in which the read-out waveform can be measured visually by an oscilloscope, etc. Also, a magnetic flux inversion number (data number) in one data block is about 320. |
