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US 2011/0084780 A1Published application
Transversal Filter
AssigneeEpcos AG
InventorsJacques Antoine Damy, Raphael Lardat, Michel Peracchia
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Abstract
The filter includes at least one acoustic track formed on a piezoelectric substrate. At least one SAW input transducer and at least one SAW output transducer are arranged in each track. Each track has a RSPUDT structure and thus a distributed excitation. The excitation function includes sources arranged in a main lobe and a tail function including at least one tail lobe. A fine and precise approximation to the desired continuous excitation function is obtained by decreasing the excitation strength in the tail function by a factor of at least 2.
Claims18
A transversal filter, comprising
- a piezoelectric substrate;
- at least one acoustic track formed on the piezoelectric substrate;
- and
- at least one SAW input transducer and at least one SAW output transducer arranged in each track;
- wherein at least one input transducer and at least one output transducer has a distributed excitation comprising
- a continuous excitation function having a main lobe and at least one tail lobe with a sign of excitation different than the main lobe;
- and
- an excitation strength S in the main lobe being greater than an excitation strength G of the at least one tail lobe by a factor of x, where 8≧x≧2, x and x is a real number.
5 more elements
Dependencies are inferred from the claim text.