We have designed and tested a 16 Bit precise Data Acquisition system. In the signal path we have used the circuit as given in the attachment.
With respect to attachment, VBias is connected to system ground.
The observation is that the noise from ground couples to the signal chain through the opamp which generates the reference for the IA(Instrumentation amplifier).
In order to avoid the noise coupling we have placed an RC filter at the +ve terminal of that particular opamp. This is given in the second attached image.
Please validate this technique and suggest other techniques to avoid this noise coupling.