| 摘要 |
<p>There is provided an optical disc recording apparatus for generating a modulation signal having a signal level switched at a period which is an integral multiple of a basic period based on main information and controlling an optical beam applied to an optical disc based on said modulation signal to successively form, on said optical disc, pits and lands or marks and spaces having lengths which are represented by integral multiples of a basic length corresponding to said basic period. A sequence of data based on auxiliary information is modulated by a signal represented by a combination of a sequence of pseudo-random numbers and a predetermined periodic signal, and recorded traces of said pits or said marks are changed depending on the modulated sequence of data, thereby recording said auxiliary information on said optical disc. Accordingly, even if a pseudo-random number sequence is used for recording auxiliary information, by making it difficult to estimate the structure of the sequence of pseudo-random numbers, anyone who attempts to produce an illegal copy finds it difficult to duplicate an optical disc which has auxiliary information recorded thereon.</p> |
