Cross-Spectral Density

[hoo-watt-wen-ware]

Does anyone know how to calculate the cross-spectral density in labview?

[CharlieM]

This example may be of some help.

http://zone.ni.com/devzone/cda/epd/p/id/196

[hoo-watt-wen-ware]

I appreciate the thought, but I have already reviewed that example. 

What I am really looking for (in layman's english):  I need to cross two signals and plot the phase relationship vs. the frequency.  While the Cross Power Spectrum.vi  does output a phase with minor modification to the example you have suggested, my experimentation with this modified example does not yield answers consistent with what I am looking for.

I understand that it is not common, but I have trouble believing that this has not been done.

Any other ideas? 

[CharlieM]

Does the magnitude output seem to be correct relative to your data?

[vickyviks]

i want to know wheter the cross spectral density performs FFT or not  i.e when we take output from csd it will give some magnitude,that magnitude is related to time or frequency

[johnsold]

Did you read the detailed help file for the Cross Power Spectrum VI?

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The Cross Power Spectrum VI computes the single-sided cross power spectrum of Signal X and Signal Y. If Signal X and Signal Y have different lengths, the VI first pads the end of the shorter input signal with zeros to make the signals the same length. The VI then uses the following equation to compute the two-sided cross power spectrum:

FFT(Signal X) x (FFT)*(Signal Y)/N^2

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Lynn