Patent ID: 6239939
Filing Date: 2001-05-29
Classification: G11B

Abstract:
Method for detection of data modulated into a timing based servo pattern prerecorded on a media, said timing based servo pattern having frames of repeated pairs of non-parallel transition stripes arranged in two bursts, one of each of said pairs in one of said bursts, said bursts separated by servo gaps, ones of said frames having said modulated data comprising shifts of at least one of said pairs of transition stripes in the longitudinal direction of said media relative to the other of said pairs of transitions stripes, said shifts of ones of said pairs in first directions representing a binary ""0"", and said shifts of ones of said pairs in second directions, opposite to said first directions, representing a binary ""1"", said method in a servo system which senses said transition stripes in said longitudinal direction of said media during relative motion with respect to said media, and detects the timing intervals between sequential said transition stripes within said bursts in said ones of said frames, comprising the steps of:comparing selected ones of said detected timing intervals to other selected ones of said detected timing intervals;determining whether said compared selected timing intervals identify a shift of said detected transition stripes representing a ""0"", or a ""1"";incrementing the number of said compared selected timing intervals representing a ""0"" in each said detected frame, resetting said incremented number to zero at the beginning of each said detected frame;incrementing the number of said compared selected timing intervals representing a ""1"" in each said detected frame, resetting said incremented number to zero at the beginning of each said detected frame;at the end of each said detected frame, comparing said incremented numbers representing a ""0"" and representing a ""1"" to a predetermined criteria, determining which of said incremented numbers meets said criteria; andresponding to said determined one of said ""0"" or ""1"" incremented numbers meeting said criteria, identifying the corresponding ""0"" or ""1"" as the bit value for said detected frame.