| 摘要 |
<p>PCT No. PCT/GB92/00014 Sec. 371 Date Jun. 15, 1993 Sec. 102(e) Date Jun. 15, 1993 PCT Filed Jan. 3, 1992 PCT Pub. No. WO92/12402 PCT Pub. Date Jul. 23, 1992.A magnetostrictive element, which may be of rectangular shape, is positioned next to a hard magnetic biasing element field with patterns recorded therein which bias the magnetostrictive element to resonate at selected frequencies, particularly harmonics of the fundamental frequency, in response to an alternating interrogating magnetic field at the same frequencies. Data may thus be encoded by selecting the frequencies at which the element will resonate. In addition to resonance at different harmonics, resonance in different modes, particularly longitudinal, transverse or flexural modes may be produced. The device may be applied to article identity systems, such as security systems but also has many other applications.</p> |
