Electronics > Projects, Designs, and Technical Stuff
OpAmp for high-Q inductor in ultra-narrow band notch filter in controller applic
Kleinstein:
The OP based filters usually need an OP GBW well higher than frequency times Q value. So a high Q at 200 kHz is not very practical with an active filter. Here an LC filter is probably better. If needed one could tune it with vari-cap or so.
There could be an option to use a kind of synchronous notch. Some AZ OPs use this method internally, so the corresponding literature could help here.
Is a really narrow notch really needed ? If it is only about getting a deep notch one could use 2 in series.
thm_w:
Are you talking about a bandpass filter or a notch filter?
https://www.ti.com/lit/an/slyt235/slyt235.pdf
nctnico:
What does the circuit do? Why do you need to filter the 200kHz signal?
T3sl4co1l:
Also, a PLL, which can be analyzed in terms of a bandpass filter.
Tim
ricko_uk:
Thank you T3sl4co1l,
that sounds interesting. How? Where can I find infos on how to do that?
Thanks
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