| 摘要 |
An 11T single signal and a 3T single signal are recorded on a DVD-RW at the optimum recording power P1 and a recording power P2 of an intensity of 85 % with relative to the optimum recording power P1, and then these signals are reproduced to calculate asymmetry values A1 and A2. If a difference (A1-A2) between both asymmetry values is equal to or greater than a reference value of 0.05, it is judged that a method using the asymmetry value is available for the OPC, and if the difference is less than a reference value of 0.05, it is judged that the method is not available. Then, the judgment result is recorded on the DVD-RW as a flag. A DVD drive judges whether or not the asymmetry value is used for the OPC (optimum power control) on the basis of the flag. Information can thereby be properly recorded irrespective of recording speed. <IMAGE> |
