| 摘要 |
A manufacturing method of a balance filter comprises preparing a balance filter that includes a first filter (40), a second filter (60), a first terminal (42) and second terminals (44). The first filter (40) has first multimode surface acoustic wave, SAW, filters (40a,40b) connected parallel. The second filter (60) that is connected to the first filter (40) includes one second multimode SAW filter (60b). A first terminal (42) is connected to the first filter (40) through a connection line (54) that runs in a direction in which connections lines between the first and the second filters (40,60) run. Second terminals (44) are connected to the second filter (60). An input terminal of the balance filter is one of the first and second terminals (42,44), and an output terminal thereof is the other. Electric signals transmitted from the first to second filters (40,60) or vice versa are in opposite phase and electric signals being input or output via the second terminals (44) are in opposite phase. An interdigital transducer, IDT (IDT14), located in the center of the second filter (60) has two electrodes; one of the two electrodes is divided into two; one of two divided electrodes is connected to one of the second terminals (44), and the other is connected to another one of the second terminals (44). The phase of the electric signals output via the second terminals (44) is adjusted by separately adjusting the first multimode SAW filters (40a,40b).
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