this might be a little silly question, but please advise me. I am trying to use two photodiodes (one for the absorbance measurement and one for the source of the light as a reference) and the voltage from the transimpedance amplifier from each photodiode connected output pin of OpAmps will be connected to the differential amplifier input to improve the SNR.
Here is my question. Let's say the output voltage from the 1st PD is V1 and the voltage output from the 2nd PD is V2. VD is V2 - V1. I want to measure VD and V2 simultaneously. So VD is the voltage difference between V2 - V1 and V2 is simply single end measurement (relative to the ground reference).
If I use two ADC (microcontroller) channels to measure those two voltages, can I connect 1) V1 - V2 as inputs to one differential amplifier and 2) V1 - ground as inputs to the other differential amplifier?
Say figure below is a dual differential ADC IC from Analogdevices.
Can I use that IC to measure those voltages without any problems? Thank you in advance for your advice.