| 摘要 |
<p>A virtual edge of magnetic tape (22) is located by successively moving a head unit (28) toward a physical edge (22EB) of tape and, at each of a plurality of transverse locations, recording a pattern P of digital information. By either successive read-back or rewind followed by reading, sensing of a read-back or acquisition signal is attempted at each location. In connection with the reading operation, a pattern is acquired from the acquisition signal using a method of amplitude invariant data recovery such as peak detection, the pattern acquired being invariant regardless of any overall amplitude envelope variations. A virtual edge of tape is determined when an acquired pattern derived from the acquisition signal does not match a predetermined pattern of information which was recorded as a corresponding pattern of flux directional transitions.</p> |
