| 摘要 |
PURPOSE:To regenerate a signal recorded in a recording medium as an image having high quality by adjusting an objective position based upon a prescribed function found by an arithmetic means. CONSTITUTION:After detecting a direction increasing the amplitude of a regenerative signal, a focus position is moved in the direction like steps to find out a reference point for function approximation. The reference point is a point on which the amplitude of the regenerative signal is almost maximized, and in order to find out the point, the focus position is moved on regenerative signal characteristics like steps C1 to C5 and the point C4 preceding a point C5 reducing the amplitude is detected and decided as the reference point P. Namely, the regenerative signal characteristics are approximated to a function and the automatic adjustment of the focus position to be the objective converging point of a focus control system can be highly accurately executed bases upon the function. Consequently, the signal having high quality can be recorded and reproduced. |
