Digital multi-rate notch filter for sampled servo digital control system

摘要

A digital servo control loop for a disk drive head position actuator implements a multi-rate notch filter in order to eliminate actuator resonances at frequencies above the sampling rate Nyquist frequency. The control loop includes circuitry responsive to the periodic digital position values sampled from embedded servo sectors which generates and puts out digital control values at the predetermined sampling rate for controlling the position of the actuator means. A digital multi-rate notch filter receives and filters the digital control values, and generates and puts out notch filtered digital control values to the actuator means at a rate comprising an integral multiple of the predetermined sampling rate.