| 摘要 |
PURPOSE:To correctly and continuously measure a jitter by dislocating suitably the relative rotary position of a spindle and a center core with a mark provided at a spindle as a standard. CONSTITUTION:After the spindle 16 and the center core 14 are adsorbed at an optional position, a signal for measuring a jitter is recorded to a rotary magnetic sheet 13 and the jitter is measured by the self-recording and reproducing that without removing the center core 14 from the spindle 16, reproducing is executed as it is. Next, the relative rotational position of the spindle 16 and the center core 14 is dislocated with an arrow 34 as a standard, re-loading is executed in the condition shown in a figure (a) and the jitter is measured. Continuously, while the spindle 16 is rotated to 120 deg. and 240 deg. as shown in figures (b) and (c), the re-loading is successively executed and the jitter is measured. Based upon the jitter measured in such way, the core dislocation of the spindle 16 and the center core 14, and the surface vibration of the magnetic sheet 13 can be correctly recognized.
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