ELASTIC SURFACE WAVE RECURSIVE FILTER USING A PASSIVE RESONATOR

摘要

An elastic surface wave filter is described and comprises a substrate adapted to propagate elastic surface waves; a first tuned transducer and a second tuned transducer having a coefficient of transmission are both disposed on a substrate to form a passive resonator for the elastic surface waves; an extra transducer is disposed on the substrate between the two transducers and connected to an input of the filter to thereby introduce an elastic surface wave into the resonator whereby a resonator elastic surface wave is obtained in the resonator, partly transmitted through the second transducer and a transmitted elastic surface wave propagates on the output side of the second transducer; a transversal filter having a predetermined transfer function without poles is disposed on the substrate on the output side of the second transducer for receiving the transmitted elastic surface wave.