| 摘要 |
PROBLEM TO BE SOLVED: To decrease the number of switches to select a passband and reduce loss when signals in a required frequency band are acquired. SOLUTION: In a 2-frequency band filter, a first SAW filter 3 that has a passband of 1.4 GHz band and a second SAW filter 4 that has a passband of 1.6 GHz band are arranged parallel, and a phase circuit 5 is provided between the first SAW filter 3 and output terminals 6a and 6b. In the 1.6 GHz band that is a passband of the second SAW filter 4, the first SAW filter 3 functions as a capacitor to allow the phase circuit 5 to parallel resonate and make it as an open impedance. On the other hand, in the 1.4 GHz band that is a passband of the first SAW filter 3, the second SAW filter 4 functions as a capacitor to make a structure that a low-pass filter is connected to the phase circuit 5. COPYRIGHT: (C)2008,JPO&INPIT
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