TRACK FOLLOWING SERVO SYSTEM FOR A DISK FILE

摘要

Functions of the head position error signal from a demodulator (21) and of input (30) to the head position actuator (26) during at least one revoltuion of the disc are combined into an eccentricity-related function. This is stored in a first-in first-out buffer (37) for addition (24) during the next revolution to output from a closed-loop track-following system compensator (23). The eccentricity function may be a track shape position signal obtd. by subtraction (34) of position error signal from the double integral(31) of actuator current; or a current profile obtd. from the difference between the second derivative of position error signal and the actual current.