An adaptive filter for the processing of position error signal in disk drives

A novel circuit used to process analog position error information in a disk drive head-positioning servo system drastically reduces noise in the signal and compensates for effects due to insufficient position sample rate at high carriage velocities. The processed signal does not suffer from envelope droop at high carriage velocities, and lends itself well to track counting algorithms. Because the filter's bandwidth and low-frequency gain are controlled by carriage velocity information, the filter characteristics adapt to environmental conditions for near optimal reduction of noise.