#### melkord

##### Full Member level 2

I need to find the range where the curve (red) is still considered linear.

For this I ploted the first (yellow) and second (green) derivative.

I also marked when the second derivative drops 60% (arbitrarily chosen) from its peak.

But I am not sure, whether this is a fair way to define the range (in this case: 20.59 - 186.91 ns).

Is there any formal criterion/procedure for this?

I know what is linearity, but a bit confuse in this situation.