| 摘要 |
PROBLEM TO BE SOLVED: To provide a code modulating method, a code modulating apparatus, a demodulating method and a demodulating apparatus which are used in recording or reproducing digital data on/from an optical disk. SOLUTION: A run length in a channel bit train has an encoding rate of 2/3 which is equal to that of (1, 7) modulation. A data bit train is converted into the channel bit train so that the run length has a minimum value 1 and a maximum value 10. Further, upon modulating any data bit train, the channel bit train does not include a pattern in which the run length 1 is continuously repeated six times or more. In addition, the channel bit train has a DSV control bit which can select the "0" bit or "1" bit in accordance with a DSV. The channel bit train obtained by using random data for the data bit train is NRZI converted into a signal. A frequency component of the signal is reduced from a maximum value of the frequency component by 20 dB or less as an amplitude ratio at a frequency of 1/10,000 or less of a channel clock frequency. COPYRIGHT: (C)2004,JPO&NCIPI
|
