Margin evaluation of PRML channels: non-linear distortions, misequalization and off-track noise performance

We present a margin-type procedure for predicting the error rate of PRML channels. Experimental error margin plots which demonstrate the influence of misequalization, non-linear distortions and off-track noise on system performance are presented. Pulse shape distortions caused by misequalization and non-linearities produce a distinct shift of the error margin plots, without changing the slope. However, off-track measurements introduce additional noise into the system changing the slope of the plots. Interpretation of experimental results is presented. It is demonstrated that error margin analysis is an effective tool for evaluating performance of PRML channels, heads and media.