摘要 |
An acoustic surface wave device using apodized interdigital transducers 32, 33, of the kind disclosed in DE 28 54 072 in which the ungrounded bus-bar 44 is inclined towards the transducer axis and a velocity compensation section 36 is provided formed by grounded dummy electrodes 37 arranged parallel to the array electrodes. The improvement comprises locating a grounded bus-bar portion 38 adjacent the inwardly inclined bus-bar portion 44' so that the facing boundary edges are uniformly spaced in the axial direction, the inclination being such that either a minimum or a side-lobe of substantially reduced magnitude of the sin x/x response is directed axially.
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