sinus fit

[cecile]

Hi! I would like to fit collected data to a sinus : I need to get the amplitude as well as the phase lag. I have looked at the fft spectra VI's but some I don't think I can get the amplitude, moreover, I am asked to open VI's that I can't find. Any idea? Someone was talking about a VI called "single tone extraction" : can someone send it to me, even if I suppose it only enables to get the frequency of the signal.
Thanks
Cecile

[LocalDSP]

Cecile,

The Extract single Tone Information.vi will do exactly what you need. The VI will not only return the frequency of your tone but also the amplitude, phase and optionally the reconstructed tone or error signal in both time and frequency domain. The VI is located in your Analyze>>Waveform MEasurement palette.

[cecile]

Thank you for this answer, but I really can't find this VI : My version of Labview is 6i and it must be a french one: might it be the reason? Could someone send this VI to me?

[LocalDSP]

Le VI en question s'appelle "Extraire une Information mono frequentielle" et est localise dans la palette Analyse>>Mesure sur Waveform.

Mais ce VI n'est pas inclu dans la version LabVIEW de base, il vous faut donc soit la version complete, soit professionelle.

Alain

[chutla]

Greetings:
In the Mathematics/curve fitting toolbox, there is a general polynomial fit. I think you can approximate a sinus fit with the correct "algorithm" input.
The Extract single tone VI. is in the Signal Processing toolbox.

[cecile]

Thank you very much for your answer, but my version of Labview is 6i and I cannot open "extract single tone information".I only have polynomial fits, but I don't like it too much. Any idea of how to do with this version?
Cecile