I've been struggling for the past few days to achieve a curve fit (or any other analysis) for this measured data (attached), from which I can obtain values of the highlighted points. There are always 2 peaks. The log axis of course complicates things, but this can be treated as linear for the sake of getting a solution, if that helps. I have access to MATLAB curve fitting toolbox, but had no luck yet (no success using a low order polynomial fit).
I would really appreciate some pointers for the right approach to solving this problem.