| 摘要 |
PURPOSE:To suppress vibrations generated at the time of positioning of a head and to position the head at high speed by detecting said vibrations by a capacitive detector and using this detecting signal to give the rotary control to a stepping motor serving as a drive source. CONSTITUTION:When a stepping motor 1 is driven to produce vibrations in a positioning mode of a head 6, the capacity limited between a slant shaft 11 and an electrode 12 varies by the rotary displacement of a shaft 2. This change of capacity is converted into the voltage by a capacity converter 13 connected electrically to the electrode 12 and amplified by an amplifier 14. This amplified signal contains also such noises undesired for suppression of said vibrations. These noises are deleted by a band pass filter 15. The center of the filter 15 is tuned to the frequency of vibrations and therefore only the twist vibration component of the shaft 2 is extracted with high efficiency. This extracted vibration component is inputted to a driving circuit 16 for motor 1. Thus the head 6 is moved onto a designated track position according to the track command signal received from a connected computer and at the same time the generation of vibrations is suppressed. |
