| 摘要 |
PURPOSE:To shorten the access time regardless of the degree of eccentricity by having the follow-up of a laser beam to a desired track on the basis of a tracking error signal. CONSTITUTION:The information is recorded and reproduced spirally or concentrically to a disk recording medium 2. A pickup is positioned every track, and an access is given again to a laser beam following on a track contained in a track group of microwidth to a followed-up track. In this case, the tracking error signal is previously held at the head position of a desired track. Then a track servo loop is opened to impress the holding signal to a tracking driving circuit 5. The track servo loop is closed at an instant when the head position of the desired track is shifted to perform the track servo control. Thus the laser beam is shifted to the desired followed-up track for the next follow-up. |
