| 摘要 |
A cavity notch filter (1) for series connection in a transmission line is disclosed which comprises a high Q cavity (2) containing therein an inductively coupled L-C series circuit (19). The notch filter (1) acts as a high series impedance at the resonant frequency of the cavity. At frequencies off resonance, the filter is characterized by low impedance so as to produce broad lateral pass bands. A multicoupler (18) for connection of a plurality of signaling devices (15) to a single antenna (16) may be assembled to comprise two or more of the filters (1) inserted into the transmission line (17); each being tuned to resonate so as to produce a notch at the respective frequency of the signaling device (15). A different signaling device (15) is connected to each of the series connected notch filters (1) at a junction (7). Energy at all frequencies is then permitted to propagate down the line except the energy at the frequency of the respective signaling device (15). This frequency is blocked by the series notch filter (1) at the junction (7) and is diverted to the respective signaling devices (15).
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