New data detection method for a HDD with patterned media

Abstract

New bit array pattern and detection algorithm for hard disk drive (HDD) with patterned media are proposed. The width of the reader is larger than a bit width, of which the fabrication cost is lower than a bit-size compatible reader. It can read several sub-tracks simultaneously, in which the bits are patterned with different phase. The readback signal is superposed by each bit response and we can extract the bit information easily because of its phase difference.I.

An MLP-based skew angle mitigation method for bit-patterned magnetic recording

“…where 𝑧 is the across-track direction, 𝑥 is the along-track direction, 𝑥 𝑟 = 𝑥 cos(𝜃) − 𝑧 sin(𝜃), 𝑧 𝑟 = 𝑥 sin(𝜃) + 𝑧 cos(𝜃), 𝐴 = 1 is a normalized peak amplitude, 𝑐 = 1/2.3548 is a constant for the relationship between the 𝑃𝑊 50 and the standard deviation of the 2D Gaussian pulse, 𝑃𝑊 𝑥 = 19.4 nanometer (nm) and 𝑃𝑊 𝑧 = 24.8 nm are the 𝑃𝑊 50 of the pulse in the along-and cross-track, respectively, and 𝜃 is the angle of the SA in degree [22]. In a conventional receiver, one read head is employed to acquire the readback signal 𝑟 𝑗,𝑘 , which will be fed to an equalizer to shape the overall channel response into a target response, where a pair of the target and its compatible equalizer is designed based on a minimum mean-squared error approach [20].…”