| 摘要 |
<p>An apparatus for sensing the position of a tape edge of a magnetic tape sliding against a magnetic head which includes a light transmitter positioned on one side of the magnetic tape and a light receiver arranged on the same side, and a reflective surface arranged on an opposite side of the tape for receiving light from the light transmitter and for reflecting light back to the light receiver. The amount of light reflected from the transmitter to the receiver depends on the amount of interference by the interposition of the magnetic tape so as to sense the edge of the tape. A light signal from the receiver is used to control the relative position of the head to the tape to correct for tape wander. One pair of light transmitters/receivers can be used, or more than one pair such as four pairs of light transmitters/receivers and corresponding reflective surfaces, to accurately position a tape head with respect to a magnetic tape, by determining a dynamic position of the tape edge. <IMAGE></p> |
