| 摘要 |
Through a provision of a level holding circuit in a focus servo mechanism for an optical disk reproducing device, a detection signal level with regard to a focusing position error, when a detection signal corresponding to a received optical beam amount shows a maximum value under a condition when not being changed over to an automatic focus loop, is sampled as an offset amount and, is held in advance in the level holding circuit, and the thus held level is utilized for effecting an automatic focusing under a just focusing servo condition.
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