公开(公告)号：HK1032657A1

公开(公告)日：2001-07-27

申请号：HK01101506

申请日：2001-03-01

Applicant: IBM

Inventor： BUI NHAN XUAN ,  FUKUDA JUNICHI ,  JAOETTE GLEN ALAN ,  KOSKI JOHN ALEXANDER ,  TSURUTA KAZUHIRO

IPC: G11B5/008 ,  G11B5/584 ,  G11B20/10 ,  G11B20/12 ,  G11B21/10 ,  G11B27/13 ,  G11B

Abstract: Disclosed are a method and a detector for adaptively detecting servo gaps in a timing based servo pattern (50) prerecorded on a variable velocity media. The timing based servo pattern has groups of repeated pairs of non-parallel transition stripes arranged in bursts (52,54,55), the bursts separated by servo gaps whose (70-75) length is variable. A servo system sensor (26) senses the transition stripes in the longitudinal direction of the media. A group interval detector coupled to the sensor detects the timing interval between the same slope transition stripes of two sequential groups of bursts (BX,BY). A divider (170) divides the detected group timing interval by a predetermined divisor to provide a divided timing interval gap detection threshold (181). A sequential stripe interval detector coupled to the sensor measures the timing interval between stripes, and a comparator (110) compares the divided timing interval and the timing interval, identifying a servo gap upon the measured timing interval at least equaling the gap threshold. The detector responds to "valid" signals (BXOK,BYOK) which indicate the validity of the detected group timing interval, repeating operation of the divider to update the gap threshold, and repeating operation of the comparator with the updated gap threshold to continue to identify the servo gaps.