Optically readable record carrier for recording information, apparatus for manufacturing such a record carrier, apparatus for recording information on such a record carrier, and apparatus for reading information recorded on such a record carrier

摘要

An optical disc record carrier having a radiation-sensitive surface and a spiral or concentric pattern of information tracks thereon. The radial displacement of each track is modulated to produce a periodic radial wobble, the frequency of such periodic displacement being modulated by a position-information signal identifying the relative positions of the tracks. During recording or reading of information on the tracks the track modulation is read by a scanning beam. A clock signal for controlling scanning velocity is recovered from the track displacement modulation, and an FM demodulator recovers the position- information signal from the frequency modulation of such displacement.