Signal processing for perpendicular recording

In order to use a magnetic recording system to store data many issues must be addressed. Inter-symbol interference, media noise, head and electronics noise and various nonlinear distortions all compromise reliable detector performance. The set of issues is the same regardless of whether the medium is magnetized in a longitudinal or a perpendicular direction. Likewise the same basic partial-response maximum-likelihood detector architecture is appropriate for both longitudinal and perpendicular recording. Details of the recording system such as the transition response, the noise power spectral density and the nature of the nonlinearities do differ greatly between longitudinal and perpendicular recording. The details of the signal processing implementation must change to accommodate these differences.