Hi Folks,
I am wokirng on a project where I have do design a multi channel analouge measurment for bilogical signals. I found a tipical analog input stage in this paper (please check figure 5)
In my project there is no possibility to install differential electrodes onto the body. Instead I have to measures potentials between electrodes and one dedicated COM electrode. Somewhere I have read that connecting negative input of 3 op amp designed instrumental amplifiers together and use it as COM signal decraese the CMRR.
On the other hand, I found a multichannel topology, like this:
where the 2 op amp design is used as instrumental amplifier, that has much lower CMRR.
Can somebody help me to decide pro or cons, which topology is better in which circumstances?
Regards,
Norbert
