| 摘要 |
PURPOSE:To decrease the length of a servo area or to increase number of tracks corresponding to the period of a change in an access code by providing a pit having two functions or over such as those of a tracking pit and a clock pit of an access code. CONSTITUTION:First and 2nd pits 4A, 4B with an offset and a 3rd pit 5 in the vicinity of them are formed to a servo area and the 1st and 2nd pits 4A, 4B detect a tracking error. Moreover, a timing of a reproduction signal of a pit is detected by one of the 1st, 2nd and 3rd pits 4A, 4B and 5 and two of the 1st, 2nd and 3rd pits 4A, 4B, 5 constitute an access code. That is, since two tracking pits have a function of a clock pit or an access code pit, the length of the servo area is decreased. Thus, the data quantity to be recorded is increased and number of tracks to be identified by the access code is increased, then the seek operation is quickened. |
