An Improved Digital Servo Burst Signal Sampling Model for Disk Drives

Abstract

In order to calculate the servo position error signal (PES) in the servo system, it is necessary to make high precision sampling and FFT calculation for the burst signal. Most designer s adopt 8bits ADC converter in the read write channel servo system of hard drive controller chip 88i6310 to cost down, and both servo system and signal system share the sampling circuit. Because of the quantitative noise disturbing during the sampling process, it is not enough to use 6bits ADC converter for the serve burst signal, and significant error exist for t he burst signal with the FFT calculation. This paper analyzed the existing servo over-sampling model via quantitative error model firstly, and provided the enhanced servo system sampling model. The simulation shows that, the enhanced solution reduces the average quantitative error from 0. 38 LSB to 0.14LSB, and improves the resolution of ADC converter from 9.5 bits to 10.8 bits.