Hi,
My recommendation:
Transform the current into voltage. Limit the value to your desired range
Then use an ADC to convert it to digital.
Now you may use software to decide what values are valid and what values are not.
And you may process the valid data as you like.
I think it's easier to "adjust" software than to adjust hardware amplifiers, limits.. and so on.
Maybe you should first specify your signals and do some simulations.
*****
Btw: noise is not DC nor a specific frequency. It is random. So it's about impossible to eliminate it.
You may attenuate all unwanted, unnecessary frequencies and this way improving signal quality.
You may use fourier analysis or correlation to find the signals of desire.
Klaus