Patent ID: 6025970
Filing Date: 2000-02-15
Classification: G11B

Abstract:
A servo control system that positions a magnetic head relative to multiple tracks of a magnetic storage medium, the system comprising:a head assembly having at least one read head for reading servo information interspersedly recorded in the multiple tracks between customer data areas and for generating a head readback signal;a servo signal filter that receives a head readback signal produced from one or more servo burst sets of the servo information, the servo burst sets comprising a repeating sequence of magnetic transitions extending across the width of servo tracks that define a servo burst A1 and a servo burst B1, both having transitions at a first frequency f1 and being located in adjacent servo tracks in a complementary arrangement, and a servo burst A2 and, a servo burst B2, both having transitions at a second frequency f2 different from f1 and being located in adjacent servo tracks in a complementary arrangement, wherein the filter includes an f1-filter and an f2-filter, such that the f1-filter produces filtered servo signal data samples with f2 frequency components removed, and the f2-filter produces filtered servo signal data samples with f1 frequency components removed;a demodulation processor that receives the filtered readback signal from the f1-filter and from the f2-filter, and produces a position error signal that indicates the read head position relative to a track, the position error signal being based on a difference between amplitudes of the servo bursts A1 and B1 and a difference between amplitudes of the servo bursts A2 and B2;a servo assembly that is activated to position the head assembly relative to the magnetic storage medium; anda servo controller that receives the position error signal and controls the servo assembly in accordance with the position error signal to maintain the magnetic head centered relative to the track.