Title :
An alternating DC track servo pattern for perpendicular recording
Author :
Hamaguchi, Takehiko ; Maeda, Hideaki ; Usui, Kazuaki ; Shishida, Kazuhisa
Author_Institution :
Res. & Dev. Group, Hitachi Ltd., Kanagawa, Japan
Abstract :
We describe an alternating dc track servo pattern as a way to avoid magnetization imbalances within the position error signal (PES) regions of the media in perpendicular recording systems. A spin-stand was used to compare signal amplitude and medium noise between the alternating dc track servo pattern and a conventional dc-track servo pattern. The alternating dc track servo pattern improves the signal amplitude and decreases the residual noise. Therefore, the new servo pattern exhibits a superior signal-to-noise ratio of the PES regions.
Keywords :
hard discs; magnetic recording noise; perpendicular magnetic recording; servomechanisms; PES region; alternating DC track servo pattern; hard disks; perpendicular magnetic recording; position error signal; servosystems; signal amplitude; signal-to-noise ratio; Clocks; Giant magnetoresistance; Magnetic heads; Magnetic noise; Magnetization; Noise level; Perpendicular magnetic recording; Servomechanisms; Signal to noise ratio; Writing; Hard disks; perpendicular magnetic recording; servosystems;
Journal_Title :
Magnetics, IEEE Transactions on
DOI :
10.1109/TMAG.2005.855300
