International Business Machines Corporation

Martin H Dost

Constantin Michael Melas

Lionel D Provazek

Francis Edward Mueller

Emil Hopner

Chung Chuan Liu

A pulse signal conditioner filters and equalizes signal pulses representing digital data whether or not obtained from a magnetic recording device. Modified low pass filters filter the pulse signals and also derive and feed forward the second time derivative of the filtered pulse signals. The filtered pulse and the second time derivative thereof are combined to slim the pulse. Further slimming is provided by delay line equalizers having three paths. A first path for attenuating the pulse signals, a second path for delaying the pulse signals for a first delay, and a third path for delaying the pulse signals for a second delay and attenuation. Pulse signals from the three paths are combined to further slim the pulse.

Compound pulse dimming circuitry for conditioning readback signals

A track-seeking and track-following servo encodement and detection system employs a servo pattern using a reference signal and control signals, the control signals having an orthogonal phase relationship to each other by cyclically revolving in phase by 90.degree., 180.degree., 270.degree., and repeating this pattern every four tracks.

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Los Gatos, CA, United States of America

Martin H Dost