Implementation of a servo positioning system on spin stand

To achieve an ultra-high track density in magnetic recording systems, high precision and efficient servomechanism is needed to position the head on the desired track. In this paper, a multiple-frequency servo encoding and modified discrete Fourier transform (DFT)-based decoding scheme is used to detect the position error signal (PES) as the feedback signal for reader servo control on a spin stand. A personal computer (PC) is used to perform the DFT and generates the PES at 8 kHz speed. A modified PZT head cartridge base is used as the positioning device on the spin stand. A closed-loop bandwidth of 300 Hz has been achieved, resulting in an 18% improvement of the tracking accuracy.