| 摘要 |
A filter device includes a super-conducting type filters connected in series with each other and is accommodated in a vacuum chamber. Operating temperatures of the filters are controlled to different temperatures from the outside of the vacuum chamber independently of each other. Each filter varies its filtering characteristics, particularly its central frequency of pass-band, in correspondence with the operating temperature, while maintaining the same pass-band width. As the filters operated at the different operating temperatures provide different filtering characteristics, the combined or resulting filtering characteristics of the filtering device can be adjusted as desired even after the filtering device is installed at a mobile telecommunication base station.
|
