| 摘要 |
PURPOSE:To facilitate the titled device to match with an external circuit by providing input output electrodes having filter function and trap function onto an elastic substrate, simplifying and miniaturizing the circuit constitution and making the impedance a desired value. CONSTITUTION:The input electrode 2 and the output electrode 3 are provided on the surface of the elastic body 1. The electrode 2 is provided with an input electrode tap 5 in a direction orthogonal to the comb line electrode of an input electrode filter 4 and the electrode 3 is provided with an output electrode trap 7 in a direction orthogonal to the comb line electrode of an output filter 6. Then the center frequency of the trap of the electrodes 2, 3 is made coincident with the center frequency of the filter part. Thus, the trap is provided at a desired frequency of the filter characteristic and it is not required to constitute trap by an external circuit, the circuit constitution is simplified and no adjust ment is required. Further, in selecting the crossing width of the comb line elec trode of the trap to a length to obtain a desired capacity, the input/output impedance of the surface acoustic wave device is selected to a desired value to facilitate the titled device to match with the external circuit.
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