Dc track edge interactions

Includes bibliographical references.We have developed an experimental method for investigating the interaction between two dc track edges by studying the track edge noise. We conclude that two edges do not interact when they are several micrometers apart, but the noise reduces nearly to zero when their separation is less than about half a micrometer. There is a transition region that exists between these two limits. The net track edge noise power from two dc edges is quantized, implying that in our experiment track edges interact around the complete revolution of the disk or not at all.This work was supported in part by NSF Grant No. ECS-880470 and NSF Presidential Young Investigator Award (Indeck) ECS-89-5714

Signal Precompensation For Multiplicative Noise In Magnetic Recording

Magnetic recording system design based on optimizing the write signal to account for multiplicative medium noise is described. The design involves placing three heads along the recorded track and is dubbed a write-read-write scheme. Medium noise has a repeatable spatial dependence, allowing compensation for local eects in addition to global average effects. A block diagram level system design is given that is capable of real-time implementation. 1 Introduction Magnetic media may be viewed as signal processing systems in the sense that the magnetic eld applied to the medium is transformed into a magnetic pattern on the surface of the medium. At a macroscopic level, for physically large distances between magnetic transitions (which correspond to recorded bits), the medium processing may be modeled as recording the applied magnetic eld directly (there are other assumptions that enter into this having to do with the saturation of the medium and the use of applied magnetic elds with am..

II. Physical Sources of Medium Noise

Abstract-- A physically based model for a magnetic recording medium is augmented by the simulation of reading with a standard head model. The medium noise generated by this model comprises a repeatable component and a non-repeatable component. The repeatable component of medium noise is partially statistically characterized. The non-repeatable component of medium noise is shown to depend on the intrinsic properties of the recording medium in a manner consistent with the medium's computed storage capacity bound