Patent ID: 7184505

Claim:
A disk having stored thereon a data sync signal pattern for use in comparing a data bit string output from a data discriminator with the data sync signal pattern to perform a data sync detection, wherein a detection unit when detecting data sync using said data sync signal pattern performs the steps of: outputting the data bit string from the data discriminator, comparing said data bit string from said data discriminator with said data sync signal pattern, and outputting a data sync signal indicating data sync has occurred when said comparing succeeds, the data sync signal pattern including: a bit string having only consecutive even-numbered “1” bits wedged between “0” bit strings, and at least one bit string having consecutive odd-numbered “0” bits wedged between “1” bit strings, wherein both end portions of the data sync signal pattern are a bit string of “0” bits or “1” bits, respectively, and a PLOSYNC pattern for a bit clock synchronization which is preceding the data sync signal pattern expresses a bit string of consecutive “1” bits.