| 摘要 |
<p>PURPOSE:To shorten a time for converging on an optimum tracking position by predicting the optimum tracking position at the time of special reproducing from deviation between the actual optimum tracking position and a theoretical position at the time of ordinary reproducing. CONSTITUTION:A microcomputer 10 outputs the initial value of tracking data from an output terminal TRD to a tracking servo means at the time of starting an ordinary reproducing action. Thereafter, tracking control in an ordinary reproducing mode is started and the initial value of the tracking data is shifted so that the detection output of a envelope detection circuit 12 may be maximum and outputted to the tracking servo means, and the control is completed by judging that the optimum tracking position is obtained when the output becomes maximum. Next, the deviation between the actual optimum tracking position and the theoretical position at the time of the ordinary reproducing is converted into a difference between the theoretical optimum position and the actual position at the time of the special reproducing so as to predict the optimum tracking position at the time of special reproducing. When the predicted data is outputted from the microcomputer 10 when the ordinary reproducing mode is changed to the special reproducing mode. Thus, the convergence on the optimum tracking position in the special reproducing mode is accomplished in a short time.</p> |
