measure of the phase purity of the measured mode shapes using a multiple reference
NOTE 1 The MMIF is given as a frequency dependent eigenvalue problem:
is the real part of the FRF
is the imaginary part of the FRF
is the force eigenvector
is the mass matrix
l is an eigenvalue.
NOTE 2 The MMIF comprises the eigenvalues resulting from the solution of the eigenvalue problem for each frequency
NOTE 4 MMIF >> 0 indicates either no resonances in the frequency range or inappropriately excited modes.
NOTE 5 The MMIF yields a set of exciter force patterns that can best excite the real normal modes. It is therefore a simple but effective method to check the adequacy of the selected exciter locations.