Optimizing the bit aspect ratio of a recording system using an information-theoretic criterion

The objective of this work is to find the optimal symbol separation T and track width TW so as to maximize the inlormation density D in bits/inch´. Here D is defined as the information density per unit area of the recording medium where Cid is the i.u.d. channel capacity, i.e., the information rate (in bitslchannel-use) between the channel input and the channel output, assuming that the channel input is a sequence of independent and uniformly distributed (i.u.d.) binary random variables, We fit the datadependent autoregressive (AR) noise model in [I] to the recording channel, and then estimate the i.u.d. channel capacity C,u by computing the i.u.d. capacity ofthe model. The method used to compute the i.u.d. capacity of the data-dependent AR noise model was proposed in.