Modal coordinates time history

Hi All,

I have a query regarding the calculation of the so called “Modal Participation Factor time signal” from a combination of

a) transfer functions (amplitude and phase for each eigenmode) obtained from "unit" accel loading in an FEM model

and

b) real accel-time test data.

I would like to somehow combine the above 2 to obtain the so called "modal participation factor time history" using suitable matlab functions.

Can somehone point me in the right direction?

Best Regards

D