Upper bounds on the capacity of the digital magnetic recording channel

Upper bounds are derived for the channel capacity of a model for a digital magnetic disk storage device. The model is similar to that of C.A. French and J.K. Wolf (1988) in that it contains a linear filter to represent the Lorentzian step response and two additive Gaussian noise processes to represent the electronic and media noises. It differs in that both the lineal bit density and the track density are parameters that may be varied, as opposed to just track density. Using typical media parameters, it is estimated that, for this model, the channel capacity (in bits per unit area) may be increased up to a factor of approximately 20 by appropriately increasing the lineal and track densities