Patent ID: 6906602
Filing Date: 2005-06-14
Classification: H03H

Abstract:
1. A surface acoustic wave filter comprising: a first acoustic channel including a first input transducer and a first output transducer, the first acoustic channel being weighted so as to define a first transfer function by the first input transducer and the first output transducer; and a second acoustic channel including a second input transducer and a second output transducer, the second acoustic channel being weighted so as to define a second transfer function by the second input transducer and the second output transducer; wherein the first and second input transducers are electrically connected in parallel and the first and second output transducers are electrically connected in parallel; the first and second transfer functions are substantially in phase within a pass band and have substantially opposite phases outside the pass band; and the bandwidth of the second acoustic channel is narrower than that of the first acoustic channel, and a first side lobe of the second transfer function of the second acoustic channel has a phase opposite to that of a main lobe of the first transfer function of the first acoustic channel.