I am trying to read two analogue input data (Electromyogram signals (bipolar signal in nature)) using arduino mega at 1000 Hz sampling frequency. The analogue inputs are coming from the device called Biopac MP150 module(https://www.biopac.com/product/mp150-data-acquisition-systems/), which can give two channels of analogue inputs sampled at 1000Hz. These two analogue signals are then passed through two voltage divider circuit for giving a dc shift to it and the output of the voltage divider circuit is fed to the A0 and A1 pins of Arduino ( The circuit is given and the code is given).
But I not getting clean signal values at A0 and A1. I find an interference between these two channels like one channel affecting the out put of other.
So I tried to use two different arduino mega for reading two analogue channels separately at two different COM ports. While I am reading one channel( one arduino) at a time the arduino serial monitor gives correct values. But when I am using two different arduino mega to read two different channels, I observe the interference between the channels like both are reading similar values.
Kindly suggests something. I am unable to understand that how can the two analogue interfere wile they are connected to two different arduinos.