| 摘要 |
<p>A magnetic token (1) bears a stripe (6, 7) incorporating a magnetic data recording medium of high coercivity having region (1 and -1) which are magnetised and separated by unmagnetised (0) regions (20). The sequences 1, 0, -1 and 1, 0, 1 define a magnetic fuse (21) which can be removed by magnetising the unmagnetised (1) region (20). The magnetic fuses (21) can either be used as a direct measure of the unexpired units on the token (1) or recorded in a read/write strip (8). Once a magnetic fuse (21) has been removed , any fraudulent attempt to 'refresh' the token by demagnetising region (20) to its former unmagnetised state is frustrated due to the hysteresis of the magnetic recording medium.</p> |
