The dependence of overwrite on proximity effects

Abstract

The widely held theories of overwrite (OW) on thin film media predict very little sensitivity to the low frequency used In the measurement. Here experimental data is shown with,% variation of more than 15 dB as the low frequency is changed from 112 to 1/14 of the high frequency pattern. Tang and Tsang's work on interpattern interactions is used to explain the sensitivity of OW to the specific frequencies used In the measurement

Nonlinear transition shift and overwrite frequency dependence

“…Phenomenological models were suggested [1], [2], but the results were not conclusive. The present report is a recording physics analysis using a Williams and Comstock [5], [6] approximation and complex variable notation [7] for simple, analytic results for thin recording films.…”

“…In general for , old transitions are so far away they have no influence. That limit is which is twice the value given in [1] when proximity effects were omitted.…”

“…C HANGES in overwrite of several decibels are observed [1]- [4] when the frequencies of the background recording and of the overwriting data are varied. Phenomenological models were suggested [1], [2], but the results were not conclusive.…”

Write bubble measurement under realistic recording conditions

“…If a series of overwrite measurements are made as a function of with a fixed , the overwrite ratio should decrease as the initial frequency increases [4]. But under certain conditions we will observe a series of minima and maxima superimposed on the descending curve as illustrated by curve (a) in Fig.…”