Information storage disk transducer position control.

摘要

The radial position of a transducer (72) used to read and/or write information into or from a spinning optical or magnetic information storage disk (66) is servo controlled by an optical doppler interferometer (80) mounted at least in part for common movement with the transducer (72). The optical doppler interferometer (80) measures the instantaneous linear velocity (V) of the information storage disk (66) at the position of the transducer (72) or at a fixed relative position with respect to the transducer (72), and the position of the transducer (72) is controlled so as to make the measured instantaneous linear velocity (V) follow a reference signal appropriate for the desired information storage track. A servo pattern is not required on the storage disk (66).