Hi,
I am doing some measurements with the AFE4490. I'm seeing a strange behavior. When the TIA resistor is set to 1M I can see a good pleth signal. However when I introduce a lot of ambient light, like in the sun, I can adjust the ambient cancellation current to prevent the ADC from saturating, but I no longer see the pleth - the signal looks like it flatlines at the ambient DC level. It's like the signal chain saturated in the signal chain prior to the ADC.
Any ideas?
thanks
Rob
