| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a band rejection filter which can flexibly respond to an addition and a change of specifications in a frequency band for a mobile communication. <P>SOLUTION: A filter unit has a first variable filter (102) and a second variable filter (103) mutually connected in series respectively, respectively having a YIG element and making a tuning frequency variable, and attenuating a desired signal within predetermined bandwidths (ΔBW1, ΔBW2) with each tuning frequencies (f1, f2) as a center. When the desired signal is at a low frequency band side, the tuning frequency (f1) and the tuning frequency (f2) are controlled to be set the same or in a vicinity mutually, and when the desired signal is at a high frequency band side, the predetermined bandwidth (ΔBW1) and the predetermined bandwidth (ΔBW2) are connected so as to become wider than either one frequency bandwidth, and the tuning frequency (f1) and the tuning frequency (f2) are controlled so that the connected band may include the desired signal. <P>COPYRIGHT: (C)2011,JPO&INPIT |
