Re: Improving Selectivity In Vintage Receivers
"Two-pole resonators" There are two resonant structures, with a controlled amount of mechanical coupling between them. There are two electrodes for each resonator, but often one on each is taken to a common ground pin, making a 3-terminal package. This saves the cost of a whole pin! but it limits ultimate attenuation. Accountancy shoots, and scores again!
These structures are done also at 10.7MHz as the common FM IF filter elements.
You can get narrower band ones done on quartz.
A double-tuned IFT is another 2-pole coupled resonator device. Mathmatically they are all similar.
DAvid
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Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done
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