I am trying to extract a small AC signal (~50mV Pk - Pk) from an Instrumentation Amplifier using a Single Supply voltage (+5V) and I want to get rid of the DC Offset (+2.5V) so I can amplify and filter the AC part (1kHz mid frequency). I want to produce a clean signal of around 700mV Pk - Pk.

Is it possible to remove the DC Part and then filter the AC signal? I can do this with a dual rail supply but this adds further noise.

The circuit is attached.

 

hi dm,
Welcome to AAC.
It is possible to AC couple the output from the IA amplifier.
What are the range of frequencies required.?
E
EDIT:
This similar circuit shows the method to remove the DC offset.

 

I think I'm going to have to reduce the frequency range to 30Hz to 250Hz. Interesting circuit, applying the mid point to the positive input terminal.
I am not getting the same output yet but I am doubling checking my circuit now.
Thank you.

 

hi dm.
When ready, post your final circuit and we can run a LTSpice simulation to check it out.
E

 

Thanks, I'm currently using Tina-Ti. I will have to check LTSpice out.

 

What's wrong with simply using a capacitor to AC couple the signal?