| 摘要 |
1,262,987. Impedance networks including electromechanical resonators. COLLINS RADIO CO. 10 Nov., 1969 [18 Nov., 1968], No. 54832/69. Heading H3U. A lattice filter, Fig. 2A, has its series and cross arm impedances Z 1 , Z 2 formed by a discwire structure 40 driven by a coil 39 surrounding a magnetostrictive rod 38. In an alternative arrangement (not shown) the rod 38 is replaced by a piezoelectric transducer. The filter may be designed to have a wide pass band response, Fig. 5, or a narrow pass band response, Fig. 6, where the poles are represented by X and the zeros by 0. In another embodiment, Fig. 10, the two cross arm impedances Z 2 are formed by a common disc-wire structure 70 and the two series arm impedances Z 1 are formed by a common disc-wire structure 71, the input and output terminals being designated W, X and Y, Z, respectively. A delay equalizer having a lattice network including a disc-wire structure is described with reference to Figs. 17-21 (not shown). In another embodiment, Fig. 22, the disc-wire structure of the lattice filter is replaced by a monolithic crystal plate 100 having pairs of electrodes 101 ... 105, each series arm impedance and each cross arm impedance consisting of such a plate. In a modification, Fig. 23, both series arm impedances Z A are formed by a single monolithic crystal structure 114 and, similarly, the two cross arm impedances Z B are formed by another single structure. According to a further embodiment a lattice-type delay equalizer may be constructed using a monolithic crystal impedance. |
