| 摘要 |
<p>PURPOSE:To execute exact tracking operation by executing tracking control based on a value for which all sample values corresponding to reproducing outputs from four heads are summed up. CONSTITUTION:A first memory means 9 is provided to store the plural sample values corresponding to the reproducing output from one head, at least, and a second memory means 13 is provided to store the total value of the sample values stored in this first memory means 9. The levels of the reproducing outputs from four heads 1-4 are sampled and the plural sampling values, which are obtained by sampling, concerning the four heads 1-4 are added 12. A comparing block 14 compares the newest arithmetic value with the maximum arithmetic value out of the four head output sample values in the past and tracking data are changed so that the arithmetic value to be obtained can be maximum. Thus, the exact tracking operation can be executed.</p> |
