R&D: Simple Skew Angle Detection and Suppression Method for bon Method for Bit-Patterned Magnetic Recordingit-Patterned Magnetic Recording

AIP Advances has published an article written by Santi Koonkarnkhai, Advanced Signal Processing for Disruptive Innovation Research Center, Nakhon Pathom Rajabhat University, Nakhon Pathom 73000, Thailand, Chanon Warisarn, College of Advanced Manufacturing Innovation, King Mongkut’s Institute of Technology Ladkrabang, Bangkok 10520, Thailand, and Piya Kovintavewat, Advanced Signal Processing for Disruptive Innovation Research Center, Nakhon Pathom Rajabhat University, Nakhon Pathom 73000, Thailand.

Abstract: “An achievement of an areal density (AD) up to 4 Tb/in² in hard disk drives (HDDs) is expected under a bit-patterned magnetic recording (BPMR) system. One of major problems in HDDs is a skew angle (SA), which depends on a read/write head position on a disk platter. Practically, if precaution is not taken, the SA can easily deteriorate the overall system performance. To maintain an acceptable system performance; therefore, we present a simple SA detection and suppression method for BPMR systems. Here, one readback sequence is used to compute a specific target coefficient before employing it to estimate the SA amount. To mitigate the SA effect, a couple of suitable two-dimensional (2D) target and its compatible one-dimensional equalizer associated with the estimated SA is utilized in the data detection process. We also propose the flipped-cross-track symmetric 2D target to reduce the complexity of the detector. Simulation results reveal that the utilization of our proposed SA method can improve the bit-error rate performance when compares with the conventional system that does not use the SA detection and suppression method, particularly when SA or AD is high.“