Author Topic: Band Pass Filter, shift gain down?  (Read 857 times)

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Offline ANTALIFE

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Band Pass Filter, shift gain down?
« on: September 10, 2016, 03:31:49 am »
Hello

I made up a BPF for with the attached circuit [RoboArm-Output.png].
I then fed in a 5mV sinusoidal waveform at various frequencies and measured the output waveform amplitude with my analog oscilloscope (rough measurement), this gave me the attached BPF response [BPF response - actual.png].
Now my question is, is there anyway to "shift the curve down"? As in I would like to have a gain of say +10dB @ 100Hz so that below 25Hz or above 300Hz I would start attenuating the waveform [BPF response - desired.png]
« Last Edit: September 10, 2016, 03:42:00 am by ANTALIFE »
 

Offline ANTALIFE

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Re: Band Pass Filter, shift gain down?
« Reply #1 on: September 10, 2016, 04:50:55 am »
I think I figured it out, with this circuit the only way to do it is by changing the gain of the instrumentation amplifier.
The next revision of the circuit will need to have the instrumentation amplifier gain constant and then have an opamp after the BPF for adjustable gain.


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