Nonlinear channel models for digital magnetic recording

Methods for identifying the digital magnetic recording channel in which data dependent nonlinear effects are present are described. The models used include the finite state machine (FSM), Volterra series, and channel state dependent transition shifting. Procedures to compute the model parameters are described, and the models are compared with a view to their accuracy and use for studying receiver performance. Results are included from prototype channels with various recording densities with significant nonlinear distortion