Patent ID: 8213105

Claim:
A method for addressing time-varying periodic disturbances in a servo control system, comprising: continuously updating, in real-time, each of a plurality of coefficients based on at least estimating a varying disturbance frequency generated by a varying radius of a magnetic tape reel, the disturbance frequency varying as the radius varies in size; providing, in real-time, the continuously updated plurality of coefficients in real time to at least one peak filter; continuously modifying, in real-time, an input signal of the servo control system in response to receiving the continuously updated plurality of coefficients, wherein the peak filter is operable in view of the continuously updated plurality of coefficients to cancel the varying disturbance frequency generated by the varying radius; and continuously adjusting, in real-time, a position of a magnetic tape track following device in response to receiving the continuously modified input signal, wherein the continuously updating each of the plurality of coefficients is performed both when the magnetic tape reel is moving in a forward direction and moving in a backward direction.