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US 2004/0164820 A1Published application
Transversal filter comprising an improved notch characteristic curve
AssigneeEpcos AG
InventorMichael Schemies
Life of this patent
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Abstract
The invention proposes a surface wave transversal filter having an input transducer and an output transducer (Aw), in which the input transducer has a primary weighting which determines the transfer function and in which the output transducer is provided with a low secondary weighting in order to improve the trap characteristic.
Claims7
A SAW transversal filter,
- comprising a piezoelectrical substrate having a respective interdigital transducer in the form of an input transducer (B) and an output transducer (A),
- in which the input transducer has a primary weighting (W1, W2) for shaping the transfer function,
- in which the aperture ApB of the input transducer is smaller than the aperture ApA of the output transducer,
- in which the output transducer (Aw) has a secondary weighting, which is much lower than the primary weighting, for improving the trap characteristic.
1 more element
The use of the transversal filter as claimed in one of the preceding claims as an intermediate frequency filter in consumer electronics or for precise-frequency applications.
Dependencies are inferred from the claim text.