MIF is calculated using this formula:

In this formula, TF is the transfer function of a response point. Usually, MIF is calculated without the "1 -", but in DEWESoft we added this so the peaks can be seen more easily.The sum goes through every transfer function in the modal test. If I can give an example, we have a setup with one excitation point and two response points, this means that we get two transfer functions as a result -> TF_1Z-/1Z+ and TF_2Z-/1Z+.The formula for MIF will look like this: