Patent ID: 6462899
Filing Date: 2002-10-08
Classification: G11B

Abstract:
A method in a servo system for initializing and calibrating at least one index servo position of at least one servo head with respect to at least one servo track prerecorded on a recording medium; said prerecorded servo track having at least two edges, each said edge comprising an interface between two dissimilar recorded servo signals, said edges on opposite lateral sides of an inner said recorded servo signal, said edges separated by a predetermined separation distance; said at least one index servo position substantially parallel to said edges and displaced a predetermined displacement distance in a lateral direction from one of said edges; said servo head moveable in said lateral direction with respect to said recording medium; said servo system having a servo detector for determining a ratio related to said two dissimilar recorded servo signals as read by said servo head, said ratio representing said lateral position of said servo head with respect to one of said edges, said servo system moving said servo head laterally to achieve an index ratio of said two dissimilar recorded servo signals representing said index servo position; and said servo system having an independent position sensor for determining the mechanical lateral position of said servo head with respect to said recording medium; said method comprising the steps of:nominally aligning said servo head at a lateral position at which said servo detector provided ratio represents one of said edges; measuring said mechanical lateral position of said independent position sensor at said nominal alignment of said servo head; repositioning said servo head laterally said predetermined displacement distance from said nominal alignment as determined by said independent position sensor; measuring said servo detector provided repositioned ratio of said servo signals; and initializing and calibrating said servo system to employ said provided repositioned ratio as said index ratio.