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OpAmp for high-Q inductor in ultra-narrow band notch filter in controller applic

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ricko_uk:
Hi all,
I'm trying to filter out a "single" frequency (200 KHz). i.e. a ultra narrow band pass filter. It works quite well using a simple high-Q LC filter but with the inductor and capacitor tolerances it is hard to tune it to that exact frequency and I need it to be very precise. I have a microcontroller on the board so ideally I want to be able to tune it for the highest amplitude.
I know that op-amps can replace inductors. So I think I should be able to adjust (through a digital pot) the resistor in the op-amp circuit that simulates/replaces the inductor.
Would such solution work?
Can I get a very high-Q response by replacing the inductor with a op-amp circuit?
If yes, how?

Many thanks :) :)

awallin:
the notch center frequency might help here... kHz, MHz, GHz ??

dzseki:
Also if you exactly know what you are looking for consider lock-in amplification instead of high-Q filtering.

ricko_uk:
Hi Awalling,
200 KHz is the Frequency.
Thank you

ricko_uk:
Thank you Dzseki,
I googled for hours to find a lock-in amplifier IC or schematic but couldn't. Do you have any pointers for a simple solution?
As I mentioned in the reply above the carrier freq is 200KHz and I do have the original clock available on the board as sinewave (I can also make it square wave).
Many thanks :)

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