| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical disk in which the reliability of demodulation of recorded data is improved, and its demodulation circuit. <P>SOLUTION: One channel bit of sub-information recorded in an optical disk is recorded with 8 periods of wobble. A channel bit "0" is recorded with 8 periods of not phase shifted wobble, while a channel bit "1" is recorded so that the phase of wobble of the initial first period is shifted by 180 degrees, further, the phase of wobble of the second period is shifted by 180 degrees again as shown by a code A of figure. Thereby, pulse width of a demodulated waveform is widened as shown in a figure (H), and the reliability of demodulation can be improved. <P>COPYRIGHT: (C)2004,JPO |
