| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve the problem that improvements on recording signal quality and stability at the time of repeating overwrite and improvements on reliability and versatility can not be attained. <P>SOLUTION: In PWM (pulse width modulation) recording, a recording wave in recording and re-writing a 0-signal of a modulated signal width nT is a continuous wave at a power level(e) and a recording pulse train in recording and re-writing a 1-signal of the modulated signal width nT is constituted of a pulse part (fp) of a time width (x) and a value (a), a multi pulse part (mp) in which a value (b) and a value (c) having a time T in total alternately continue (n-n') times at a duty ratio of (y) and a pulse part (op) of a time width (z) and a value (d). The time width (x), the duty ratio (y) and the time width (z) are values satisfying 0.5T≤(x)≤2T, 0.4≤(y)≤0.6 and 0.5T≤(z)≤1T, respectively, n' is a positive integer of n'≤n, and (a and c)>e>(b and d) is satisfied. <P>COPYRIGHT: (C)2007,JPO&INPIT |
