公开(公告)号：CA2013058C

公开(公告)日：1995-02-14

申请号：CA2013058

申请日：1990-03-26

Applicant: IBM

Inventor： BELSER KARL A ,  DOUNN PAUL J ,  HENDERSON IAN E ,  KADLEC RONALD J ,  ROBERTS SPENCER D

IPC: G05B19/23 ,  G11B7/085 ,  G11B7/09 ,  G11B21/08 ,  G11B7/00

Abstract: ?U9-88-008 A track-seeking system for an optical disk using a velocity control loop with partially-digitized velocity measurement. A quadrature signal is generated based on summing the halves of a position error signal to give directionality to track-crossing counts. A so-called piggy-back construction, wherein a fine positioner is carried by a coarse positioner, is employed. Feed-forward controls are provided from the fine to the coarse positioner. At track-capture time, the dynamic range of the fine positioner is momentarily increased.