| 摘要 |
PURPOSE:To correct the irregularity of the characteristic of a magnet and the influence due to an external force by measuring the influence of the distortion and the external force to the magnetic characteristic before starting an operation, obtaining the difference from an ideal value and storing it as a correction value in a memory. CONSTITUTION:An output A of a constant-voltage generator 1 is supplied through a power amplifier 4 to a voice coil motor VCM before starting the operation. On the other hand, a position signal PS fed back from a head is differentiated by differentiators 2, 3, converted into an acceleration C, and added to the output A. A current signal CRS flowed to the VCM at this time is converted by an A/D converter 11 into a digital signal, and a memory 12 stores the digital signal and a cylinder position signal CAR. The magnification of a multiplier 10 is corrected by the correction value F stored in the memory 12 at the operation time. |
