| 摘要 |
PURPOSE:To position the magnetic head of a magnetic recording and reproducing device with a high accuracy. CONSTITUTION:The value of a differential signal E obtained from two servo track reproducing heads 21a and 21b is compared with the threshold of a differential signal level discrimination circuit 4, then when the differential signal E is within the threshold, a stepping motor driving circuit 7 is not operated. When the differential signal E exceeds the threshold, the magnetic head is positioned by rotating a stepping motor 8 in the direction chosen by a polarity detector 6. |
