Bitshift errors due to wideband noise in digital magnetic recording

An expression is derived for the PDF (probability density function) of the bitshift due to additive noise which assumes that the replay signal and the noise have comparable bandwidths. The error rate against signal-to-noise ratio characteristic is computed and it is shown that the effect of noise bitshift is more severe than is suggested by the usual error function expression for the error rate. Characteristics are compared for white and coloured noise at the differentiator input, and it is shown that at low packing densities the modified PDF for noise induced bitshift give error rates which more closely follow experimental results