Hi,
We are in the process of calculating the SPO2 from the AFE4900EVM.
we have used the equation SPO2% = 110 - 25*r
But we observed it is not accurate and gives us different r values for the same SPO2% in different subjects.
Following is the method used to calculate the r value in the case of a negative offset cancellation at the amplifier input
Red AC signal : Red local maxima - Red local minima
Red DC signal : (Red local maxima + Red local minima )/2 + (Red offset cancellation current x Gain)
Similarly,
IR AC signal : IR local maxima - IR local minima
IR DC signal : ( IR local maxima + IR local minima )/2 + (IR offset cancellation current x Gain)
r = ((Red AC signal)/(Red DC signal))/((IR AC signal)/(IR DC signal ))
Can someone please pinpoint if any fault in the calculations or guide on acquiring a better SP02 value?
Thank you
