International Business Machines Corporation

Karl Heinz Schaller

Volker W Zimmermann

Arno Matla

Helmut P Louis

Volker Zimmerman

To compensate for drops in the amplitude of signals read from magnetic records, in particular servo signals, a complementary correction signal is produced from the signal drops by rectifying, low-pass filtering, differentiating, integrating and forming the absolute value. This complementary correction signal is added to the defective signal to obtain a signal which has roughly been corrected to the original magnitude prior to evaluating and forming the position error signal (PES).

Magnetic disk track following servo burst amplitude drop compensation

The surface of a magnetic disk (23) is divided into servo sectors (S.sub.1) and data sectors (S.sub.2). A selectively positionable magnetic head (24) effects, in predetermined time intervals controlled by clock signals of a clock sensor (26), the transfer of servo and data signals. The servo signals sensed in the servo sectors are used for the track following control of the magnetic head. The servo markings (Ma) recorded in the servo sectors (S.sub.1) are arranged, with twice the width (2d) of the data tracks in radial distances of one respective track width (d), one beside the other in a row along a disk radius. In each servo sector at least three rows (A, B, C) of servo markings (Ma) are provided. The servo markings are arranged in track direction one behind the other in such a manner that between each of the rows (A, B, C) a distance (g) is formed, and that each servo marking of one row overlaps a servo marking of the following row by one track width (d).

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Herrenberg, Germany

Karl Heinz Schaller