MAGNETIC TAPE POSITION SENSING

摘要

A length of magnetic tape extending along a tape path in a cartridge shell and having its ends wound one on each of a pair of reel hubs is formed adjacent each end with a repetitive pattern of holes. The patterns of holes at the two ends of the tape are different to distinguish the ends from each other and two additional sets of holes located more centrally of the length of tape than and distinguishable from the repetitive patterns demark the ends of the desired recording area on the length of magnetic tape. A plurality of photocells are used to detect the holes and to distinguish the repetitive patterns of holes from each other and from the additional sets of holes to provide unambiguous sensing of the beginning of tape, the end of tape and the desired recording area.