| 摘要 |
Narrow-band bandpass filter with electronic tuning within a frequency range predetermined by signals emitted by an electronic control, comprising: a body 2 delimiting a tuned cavity 3 and including two opposing walls 4, 5, one 4 of which possesses a series of emergent openings 6; a series of resonators 7 each extending from the other of the opposing walls towards one of the emergent openings 6 and each having an extension 9 exiting from the tuned cavity 3 through the corresponding opening; a set of tuning capacitors for each of the resonators including capacitor plates 17 arranged around the respective extension 9 outside the tuned cavity 3; and means selectively exciting and blocking the capacitor plates 17 as a function of the said signals in order thus to integrate the respective tuning capacitors of the respective sets into, or exclude them from the electrical circuit of respective resonators and hence vary the filter's tuning frequency band. <IMAGE>
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