Patent ID: 6278571
Filing Date: 2001-08-21
Classification: G11B

Abstract:
A detector for adaptively detecting servo gaps in a timing based servo pattern prerecorded on a media, said timing based servo pattern having groups of repeated pairs of non-parallel transition stripes arranged in two bursts, one of each of said pairs in one of said bursts and separated by an ""A"" interval, said bursts each separated by servo gaps whose length is variable in the longitudinal direction of said media based on the lateral position on said servo pattern, intervals between said transition stripes in said longitudinal direction within a burst of said group being substantially identical and less than the minimum said servo gap, said media subject to velocity variations, in a servo system having a sensor which senses said transition stripes in said longitudinal direction of said media during relative motion with respect to said media, and a group interval detector coupled to said sensor detecting a ""B"" timing interval between parallel said transition stripes of two sequential said groups of bursts and spanning two said servo gaps, said detector comprising:a divider coupled to said group interval detector and having an output, said divider dividing said detected group ""B"" timing interval by a predetermined divisor to provide a divided timing interval gap detection threshold at said output;a sequential stripe interval detector coupled to said sensor measuring the timing interval between sequential said sensed transition stripes; anda comparator coupled to said sequential stripe interval detector and to said divider output, and having a gap detect output, said comparator comparing said divided timing interval and said sequential timing interval, said comparator providing a servo gap identification signal at said gap detect output upon said measured sequential timing interval at least equaling said divided timing interval gap detection threshold.