Is there a SubVI that will compute cross coherence of two signals?

[ejguindo]

I am trying to compute cross coherence between two time waveform signals to determine if one is a time-shifted version of the other, and if so what the time shift is.  I do not find a SubVI in LabVIEW that seems to perform this function.

[Henrik_Volkers]

try the search function in the functions palette (in the upper right corner).

 signal processing-signal operation

What version do you use? 

[seVEMes]

If you have the Sound and Vibration Toolkit try going to the palette: Sound and Vibration » Frequency Analysis » Baseband FFT. Also try Sound and Vibration » Frequency Analysis » Baseband FFT » Baseband Subset and Sound and Vibration » Frequency Analysis » Zoom FFT.

The first one is probably your best bet.

[ejguindo]

I am using Version 8.6 with the Sound and Vibration Toolkit.  I have searched the functions pallet and find Coherence, Cross Power, and Cross Correlation, but these are not exactly what I am looking for.  I searched the NI website and returned the following link to a Blackfin Cross Coherence VI.  I think this is what I need, but I don't believe it is in my current product.  From the equation at the end, I may be able to build it, but with my level of experience, I wasn't sure I would get it coded right, and thought sure it would have already been built for 8.6.

http://zone.ni.com/reference/en-XX/help/371653B-01/lvblacklibdsp/bf_crosscoherence/

[CharlesD]

Those VIs are only compatible for Blackfin, and use drivers and function calls that are specific to blackfin and embedded controllers.  Unless you are program embedded controllers I don't see these functions working for you.  However you could open up that function and try to replicate it in a regular SubVI using regular LabVIEW function calls!

[ejguindo]

How do I open that function?  This appears to be the help file, and I was unable to see a link to open the VI itself to see how it is constructed.  SInce I don't have the Blackfin, I do not have the VI set it is referring to.

[bruno_costa]

Hi,

If you have MathScript you can use cohere function,

Another way you can use Dual Channel Spectral Measurement Express VI