FFT

[galbich]

Bonjour

je souhaiterai convertir un tableau de données en FFT sachant que ces données sont acquises avec une fréquence de 20 KHz.

merci d'avance  pour votre aide

[ML927]

Hey,

Have you looked this document : http://www.ni.com/white-paper/4541/en/ ?

[LocalDSP]

Bonjour,

     Pour faire ca il vous faudra faire... oops I mean, to do this you need three steps

1 - Read your data file and and convert it to a 1D array of double. The Read Delimited Spreadsheet.vi in the File I/O palette should work for you.I noticed that your data file uses ',' (comma) as decimal point so if it doesn't work you may have to check the type of decimal point your LabVIEW is configured for (Tools >> Options menu). Alternatively make a copy of your file and do a Search and Replace ',' --> '.'

2 - Next you need to build a waveform with the sample rate information dt = 1 / Fsampling = 50 us.

3 - Finally input the waveform to the FFT function of interest (FFT. Power Spectrum, ...) from the Signal Processing >> Wfm Measure palette. The output is an XY array that you can graph directly or analyze further.

Bonne chance!

[LocalDSP]

Oops correction... the output of the FFT functions is a cluster that can be displayed directly on a waveform graph, not an XY graph.

[galbich · Accepted solution]

Bonsoir 

Thank you very much