| 摘要 |
1,156,333. Magnetostrictive apparatus; gramophone pick-ups. STANDARD TELEPHONES & CABLES Ltd. 10 Feb., 1967, No. 6512/67. Headings H3U and H4J. A magnetostriction device comprises, Fig. 2, a T-shaped substrate, e.g. of glass, coated on one surface with a film 6 of magnetostrictive material, e.g. iron or nickel, to form a reed member. The film 6 is cut away by strips 7, 8, 9 and has contact areas 10, 11 deposited thereupon connected to terminals, whereby an electric current passing between the terminals is caused to take a meandering path 12. The current induces a strain in the film 6 causing the reed to vibrate in flexure at the frequency of the electric signal. In an alternative use of the reed member as a strain gauge, a static bias current is applied between the terminals or remanence may be used. The reed member may be caused to vibrate in the longitudinal mode by exciting it at the longitudinal frequency or by applying a cut-away film, similar to the film 6, on the other surface of the substrate, the electric signal being passed through both films. In another embodiment (not shown), a cylindrical substrate is provided with a helical film of magnetostrictive material to induce torsional vibrations. To reduce skin effect at high frequencies the magnetostrictive film may be coated with low resistance material, e.g. copper or gold. A further magnetostrictive film may be deposited on the low resistance coating. In another embodiment, Fig. 4A, relating to an electromechanical bandpass ladder filter, the magnetostrictive film 16 is coated on a rectangular flexible insulating substrate. Six windows 19 and two windows 20 are cut out from this assembly to form a coupling element 39 and four resonator elements 40 and to provide locations for input and output magnetostriction devices 41, 42 similar to the device shown in Fig. 2. Each device is formed by the removal of strips 23 ... 26 of the film 16 to provide two isolated film regions 21, 22 to which input and output terminals 27, 28 are connected. The resonator elements 40 form two rows, the two elements of each row being coupled to each other and to the device 41 or 42 of that row by the element 39. In another embodiment of a filter (Fig. 5, not shown), twelve windows are cut out from the film and substrate assembly to provide two transmission paths between the input and output magnetostriction devices and the filter has attenuation peaks in the upper and lower stop bands.
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