A class of partial response systems for increasing storage density in magnetic recording

A class of partial response systems of the form Pn(D) = (1 - D)(1 + D)ⁿ, where D is the delay operator and n is a non-negative integer, is described for the spectral shaping of the readback signal to achieve higher recording densities. The properties of the desired response at the detector input are examined. It is shown that the use of higher values of n can result in higher recording densities without excessive noise enhancement, or, equivalently, pulse slimming. The cost for increased density is higher complexity in the required maximum likelihood detector.