| 摘要 |
PURPOSE:To obtain an index pulse signal with less jitter even at the time of a low speed rotation by providing any one of a Hall element, a Hall IC and a magneto-resistance element to detect a magnetic flux from a metallic rod. CONSTITUTION:A magnet 5 to fix a disk 1 having a hub penetrated with the metallic rod 4 to a spindle 6, any of a Hall element, a Hall IC and a magneto- resistance element to detect a magnetic flux from the metallic rod 4 magnetized by the magnet 5 and a means pulsizing and forming an index signal from an output signal from the Hall element, the Hall IC or the magneto-resistance element are provided. Since the magnetic flux is detected by, e.g., a Hall IC, a detection signal of the same level independently of the rotational speed is obtained. Thus, an index pulse with less jitter even at a low speed drive is obtained.
|
