| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical disc device which enables laser power adjustment to be smoothly performed without requiring special hardware configuration such as a peakhold circuit. <P>SOLUTION: A mark level (a wave height value) is obtained from an RF signal during recording. This is divided by a linear value in proportion to recording power, and a normalized wave height value is calculated. The calculated normalized wave height value is compared with a target value and a set value for the recording power is adjusted. The figure shows the calculated result when a measured value for the mark level (the wave height value) is divided by the linear value and normalized. In the figure, the normalized wave height value decreases monotonically in accordance with increase of laser power. This enables deviation direction of the recording power to be detected based on the normalized wave height value. Around 21 mW which is a power margin range, variation of the normalized wave height value level is comparatively large. Thereby, the amount of the deviation for the recording power can be smoothly detected based on the wave height value level after the normalization. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
