Trigger signals

[Elisabet_Blom]

I have time signals from a bumptest and have to recalculat the signals to new FRFs.  I have a few bumps and want to do averaging . Have anybody a suggestion of how to do this?

[DanC12]

In the Analsis tab, you have Signal Analysis => FFT , but I don't know how FRF relates to FFT. It doesn't look like theres a specific function. 

Whats the calculation for FRF? Maybe you could look at defining your own calculation, or use the DIAdem Script?

[Brad_Turpin]

Hi Elisabet,

If your'e looking for the frequency-based transfer function, then the "FFT with Two Time Signals" in the Signal Analysis palette will do that.  You should also look at the "Shock Response Spectrum" in the Signal Analysis palette to see if that will serve your needs.

Otherwise, there's the full FFT (Real+Imaginary), Auto-Correlation and Cross-Correlation, and that's it.  So if none of those work for you, then as suggested you'd need to run analysis outside DIAdem.  Note that DIAdem 2020 now supports python scripts, so perhaps there's an FRF option in the numpy module or some other one.

Brad Turpin

Principal Technical Support Engineer

National Instruments