METHOD FOR DETECTING ECCENTRICITY OF DISCRETE TRACK MEDIA

摘要

A method for especially detecting high order eccentricity and eccentric direction of a track of DTM without referring to a servo pattern. The method for detecting eccentricity comprises a step for writing predetermined data in a predetermined region while moving a head stepwise in the radial direction for the DTM; a step for acquiring a plurality of envelop data by reading out the data written in the predetermined region while moving the magnetic head on an eccentric track by a plurality of amplitudes and phases, and searching a primary eccentricity follow-up track capable of eccentricity detection in the next stage by judging the smoothness of the waveforms of the plurality of envelop data thus acquired; and a step for acquiring polyphase envelop data by reading out the data from the predetermined region while moving the magnetic head position stepwise in the radial direction under a state following up the primary eccentricity based on the primary eccentricity follow-up track, operating the track decimal value of each sector from the polyphase envelop data thus acquired and reconstituting the eccentric shape by connecting them in sequence for every sector.