Gain control for a dual burst, dual frequency PES servo pattern

摘要

Real-time gain control calibration is provided for each frequency of a disk drive storage system using dual-frequency, dual-burst position error sensing (PES) signals. Automatic and independent gain control for each PES servo burst frequency component is achieved with an automatic gain control (AGC) mapping that determines the approximate head position and performs an appropriate gain calibration for each servo burst frequency or with sector by sector normalization performed for each PES signal sample. For the AGC mapping, calibration is performed either with calibration tracks or with an in situ method. Both mapping and normalization methods provide accurate automatic gain calibration during signal readback.