An off-track capability model including noise

Abstract

An analytical model for off-track capability (OTC) is developed. The model is built on the assumption that, for a given channel, the overall signal to noise ratio (SNR) determines the bit-error-rate (BER). Written magnetization consists of a data track, adjacent tracks and attendant erase bands, and previously written "old information." SNR is determined by the position of the read-back sensor over the medium, and by the characteristic signal, electronic noise, and media noise powers. These parameters are presumed constant for a particular head, disc, and linear density. OTC is determined as the off-track distance beyond which the SNR falls below a given threshold value, which can be correlated to a threshold BER. We compare OTC as predicted by the model to experimental measures of OTC as the track pitch is varied.