| 摘要 |
PURPOSE:To detect a track shift with improved accuracy, by using the number of servo bits of a servo track which contains a servo signal region of a parallelogram having two sides parallel to the lengthwise direction of a tape and a demagnetizing region formed alternately. CONSTITUTION:A servo signal region 12 of a parallelogram and a demagnetizing region 13 of the same shape as the region 12 are formed alternately and with each track pitch to a servo track 2A provided to a magnetic tape. A servo bit 14 of a certain frequency is recorded to the region 12, and at the same time a sink bit 15 of a different frequency from the bit 14 is recorded at the area close to the center of the region 12. A rotary head 5 scans across the track 2A to obtain the number of bits 14 having levels higher than the slice levels obtained before and after the bit 15 as well as the number of bits 14 having levels higher than the slice levels obtained before and after a blank. As a result, it is possible to obtain a shift from a scan position A as well as a shift extent of a track. |
