Calculate coherence for a series of Impacts

[arcranda]

Calculating coherence has been discussed several times - including this knowledge base article and community example. But I'm still missing something.

How can I calculate the coherence so it updates after each hit (right now it's always 1)?

On a related note, I'm assuming the Y signals in the FRF(Mag-Phase) are the response and the X signals are the stimulus...Transfer Function.vi explicitly states Response and Stimulus for its inputs, but FRF(Mag-Phase) doesn't.

I attached an abridged version of what I've attemped.

[Z'atari]

Check this example:

http://zone.ni.com/devzone/cda/epd/p/id/5810

You will see that to measure coherence you need to input the same size array or waveform. In your VI, you are sending your input through a shift register and augmenting the size of your array.