| 摘要 |
PURPOSE:To suppress the influence due to the eccentricity of a magnetic sheet and the drop-out of a reproducing RF signal to the minimum by sampling and adding a reproducing RF signal obtained in the vertical synchronizing period at an unequal time interval so as to come to be a high frequency at the circumference and the center of a screen and detecting envelope data used for a tracking control. CONSTITUTION:A CPU7 fetches plural reproducing signals obtained during the vertical synchronizing period specified by a vertical synchronizing signal VD from a synchronizing separating circuit 9 by the action of an A/D converter 6 due to a sampling pulse P1 of the unequal interval which is the output of a pulse generating means 71, adds the sampling data from the A/D converter 6 over the vertical synchronizing period by an adding means 72, thereby detecting the envelope data used for the tracking control. The CPU7, first, after the CPU7 shifts a reproducing head 2 to the vicinity of a designating track and stops, executes the tracking control so that the head shifts to the position where the peak value of envelope detecting data can be obtained and the best reproducing screen can be obtained. Thus, the influence to the sampling data due to the drop-out can be suppressed to the minimum.
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