Radial separation distance determination for a data storage medium

Abstract

An apparatus and method for determining a separation distance between radial locations on a data storage medium, such as an optical disc. A first number of channel bits are detected at a first radial location of the medium, and a second number of channel bits are detected at a second radial location. The radial separation distance therebetween is determined in relation to the respective first and second numbers. Preferably, the first radial location is a first track on the medium, and the second radial location is a second track on the medium. Preferably, a motor rotates the medium, a data transducer transduces readback signals from the first and second locations, and a processor determines the respective numbers of bits from the readback signals. The radial separation distance is preferably used to authenticate the medium.

Dependencies are inferred from the claim text.