Patent ID: 7400569

Claim:
An optical disc on which wobbled grooves are concentrically or spirally formed, and physical address information is recorded by modulating groove wobbles, wherein address information is formed by M wobbles per bit as a basic unit, and the address information is NRZ-recorded, where integer M is the number of wobble waves, a sync signal used in sync detection of the address information is formed by N wobbles per bit as a basic unit, and the sync signal with that configuration is recorded on the head side of the address information, where integer N is the number of wobble waves and M=2N, and the sync signal is formed using a pattern, which is selected from signal patterns, and has a largest or second largest minimum Hamming distance to all address information symbols and an out-of-phase sync signal among the defined signal patterns and has a smallest number of phase changes in the sync signal.