| 摘要 |
PURPOSE: A duplexer and communication machine equipment is provided, which is suitable for the communication system of a wide band and narrow separation, while achieving a satisfactory characteristic. CONSTITUTION: A duplexer includes a first filter containing a frequency variable filter formed by connecting an impedance variable element to dielectric resonators(R1,R2), a plurality of surface acoustic wave filters(SF) having different frequency pass band, and a second filter containing a switching circuit(SW) for selecting one of SAW filters. The first filter is used as a transmission filter and the second filter is used as a receiving filter. The first filter acts as a band elmination filter and the second filter acts as a band pass filter.
|
