Frequency interval

[celynn]

Hi can someone advise me the difference between the waveform i plotted in Labview and Matlab?

I am trying to achieve the Matlab version.

[Conseils]

The frequency characteristic looks identicle.

If the signals were aquired using different hardware or the Labview is real world and the Matlab a simulation then this might account for the additional noise on the data presented in Labview.

First you should check that you have not introduced noise into the system (lack of shielding, poor or open connections, noisy equipment, lack of anti-ailias filters etc).
Then check that the dynamic range is adequate for the signals you are trying to aquire.

Finaly is the treatment of both signals the same in both systems?

[celynn]

Indeed they look similar.

i used the same set of time signals for both and i found out that the magnitude of the power spectrum density from labview is different from the power spectrum density value i obtain from Matlab.

[TylerS]

celynn,

What LabVIEW functions are you using to get the power spectrum and what Matlab functions are you using? It's possible that they use slightly different algorithms which provide slightly different results. I don't know for sure though. If you want a quick solution in LabVIEW, though, you could use the Matlab Script Node to run the Matlab code from within LabVIEW.

Tyler S