Hello,

I need to calculate the FRF for a mechanical system where the exitation has its origin from a gearbox. I generated simulation data while the mechanical systems rotates under operating conditions. I generated data of velocity an acceleration. For my acoustical analysis I need the frequency response function. So I wanted to calculate them by using the function modalfrf. But I am not sure if I can use this function due to the fact that I do not have a hammer or shaker exitation. So is it possible to calculate the FRF with this function or do I need to use another function?

Thank you very much in advance.

## Best Answer