A nonlinear model for magnetic recording channel with an MR head

We propose a model for a magnetic recording channel to estimate the influences of the nonlinear distortion of an MR head on the performance of the PRML system, using a superposition of a magnetic field and a transfer curve obtained by a micro-magnetic model. A readback signal was simulated using a nonlinear model. The simulated signal was compared with an actual readback signal in the analysis of the isolated pulse, frequency response, and extracted dipulse response. We found that the nonlinear model represents actual MR head output satisfactorily, and that the performance of the PR4ML system was affected by the nonlinear distortion of the MR head for a 5% loss of the amplitude margin when the asymmetry was within 10%