Extended Kalman Filter Based Acquisition Timing Recovery for Magnetic Recording Read Channels

In synchronous timing recovery approaches often employed in magnetic recording readback channels, the timing error detector (TED) output is assumed to be linearly related to the underlying phase offset. However, the noisy readback signal samples in high-density magnetic recording systems are nonlinearly related to the underlying timing disturbances. Thus, a nonlinear state space models may describe such systems more accurately and an improved timing recovery solution may be obtained via an extended Kalman filter (EKF) approach. In this paper, EKF based timing recovery is investigated for the acquisition stage. Numerical simulations indicate that the EKF based timing recovery scheme yields smaller root mean square (RMS) error in timing estimates, which enables it to handle larger timing errors more reliably. In addition, the proposed method converges faster than the conventional timing recovery schemes, which may allow us to reduce the length of the preamble pattern used for the acquisition.