| 摘要 |
<p>A disk evaluation device capable of making a highly reliable disk evaluation even of a recording disk recorded at high density. A read sample value sequence is generated by sampling a read signal read from a recording disk at a timing of a clock of the same frequency as that of the channel clock, and an amplitude-limited read sample value sequence is obtained which is generated by limiting the read sample value sequence to a predetermined amplitude limit value. When the interval between the maximum sample value and the minimum sample value of the amplitude-limited read sample value sequence corresponds to a predetermined high-band wavelength interval, the maximum sample value and the minimum sample value are increased to create a high-band-enhanced read sample value sequence in which the high-band signals are enhanced. The high-band-enhanced read sample value sequence is converted to an analog high-band-enhanced read signal at a timing of a clock of the same frequency as that of the channel clock and, from this high-band-enhanced read signal, only the components whose frequency is equal to or lower than a predetermined cutoff frequency are obtained as the evaluation read signal. Then, the jitter of the binary signal, generated by converting this evaluation read signal to binary signals using a predetermined threshold value, is output as the disk evaluation value.</p> |
