| 摘要 |
The filter according to the invention relates to helical resonators, in which the part located between a resonator coil 12, 13 and a conductive casing located at a distance from the latter consists at least partially of a ceramic piece 11, the surface of which is lined with conductive coupling spots 14, which constitute capacitances with one another and the conductive casing. The coupling spots offer selective capacitances for adjusting the load capacitance and hence the resonance frequency of the resonator. It is possible to use the coupling spots also in a capacitive coupling between the resonators or as coupling capacitances in a coupling to those parts of the circuit situated outside the resonator. <IMAGE>
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