| 摘要 |
PROBLEM TO BE SOLVED: To easily set erasing power and to optimize laser power by storing each power when a reproduced signal mark level exceeds or does not exceed a threshold value respectively, and setting the erasing power by using the stored value. SOLUTION: After a mark is recorded in a track (a), a value obtained by experiment is defined as an initial value of erasing power Pe, then a laser is emitted, a signal is reproduced from a track (a), it is compared with a reference value by a discriminating circuit 3, and the result is latched by a latch circuit 4, sent to a system control circuit 5 to discriminate whether a level is H (high level) or L (low level). Then respective values of erasing power Pe when an output of the discriminating circuit 3 is changed from L to H and from H to L increasing minute quantity of erasing power Pe are stored, and erasing power Pe to be set is calculated. When the range between both values is divided and erasing power Pe is set, a weighted average value by division ratio of α/β is defined as the erasing power Pe value, so that an optimum value can be obtained by selecting α and β adequately. |
