Effects of timing information for a magnetic recording channel in the presence of non-linearities

Nonlinear effects arise in the high-density magnetic recording, which causes a performance degradation of the corresponding detector. Design of the timing recovery is crucial for the detector, and it becomes complicated in the presence of the nonlinear effects. In this article, we examine the effects of the Muller & Mueller´s phase detector for a nonlinear magnetic recording channel. For simplicity, computer simulations are used to demonstrate the nonlinear effects for a partial response class IV equalized channel. The nonlinear effects, transition shift and partial erasure, are simulated. The results show that a transition shift causes a non-uniform shift of the S-curve with a different timing error, and the partial erasure effect decreases the slope of the S-curve.