Head selectable servo notch filter and method for improving servo system performance

摘要

A notch filter for a disk drive servo system is disclosed having selectable filtering capability. Different servo notch filters for different heads in the actuator head stack are provided. The notch filters may be selected to remove different resonant modes associated with the different disk drive heads. Each of the plurality of notch filters is tuned to remove a resonant frequency associated with at least one magnetic head of the disk drive. In operation, a notch filter is selected to remove a resonant frequency associated with a magnetic head commanded to write or read data to or from the disk drive. The notch filter system includes a multiplexor for controlling the selection of the notch filters. The multiplexor receives commands from a servo processor to control the selection of a notch filter. Different notch filters can be utilized, including series tapped notch filters or parallel notch filters. The notch filters are run continuously to avoid transients resulting from initialization of the notch filters.