Notch Filter

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PY5FT
Posts: 41
Joined: Wed Dec 22, 2004 1:51 pm
What radios do you own?: Kenwoods...

Notch Filter

Post by PY5FT »

Dear OM's

I like to know how work the Series Notch Filters. If u can help-me with diagrams or a source where i can learn about, I thanks. The major dubs are in the loop section, the heart if this filter type.

Best Regards, Antonio
Actual PY5AB
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Bruce1807
Posts: 1203
Joined: Mon Jan 16, 2006 7:18 am

Post by Bruce1807 »

a series notch filter is designed to suppress close
frequency interference signals. A particular frequency
response can achieve by cascading a few notch filters.



now the technical explanation

A cavity notch filter for series connection in a transmission line is disclosed which comprises a high Q cavity containing therein an inductively coupled L-C series circuit. The notch filter 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 for connection of a plurality of signaling devices to a single antenna may be assembled to comprise two or more of the filters inserted into the transmission line ; each being tuned to resonate so as to produce a notch at the respective frequency of the signaling device. A different signaling device is connected to each of the series connected notch filters at a junction . Energy at all frequencies is then permitted to propagate down the line except the energy at the frequency of the respective signaling device. This frequency is blocked by the series notch filter at the junction and is diverted to the respective signaling devices.
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