| 摘要 |
A surface acoustic wave bandpass filter has a piezoelectric substrate for propagating a surface acoustic wave. An input transducer is formed on the substrate, with a pair of interdigital electrodes, for exciting a surface acoustic wave in response to an electrical signal. An output transducer is also formed on the substrate, with essentially the same structure for developing a filtered electrical signal from the surface acoustic wave propagated in the substrate. The input and output transducers are arranged so that the distance between them (L) satisfies the relationship: lambda /2 n<L< lambda /2 (n+1) (n is a positive integer), and lambda /2 represents the distance between the centers of adjacent electrode fingers.
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