fft

[pad]

I currently use the program put in example with LabWindows5.0: " MuliRecordAcquisition ". I would like to make a frequential analysis (FFT) on the second graph.
What is the function?
How use it?
Thank you

/*- Obtain the actual sampling rate used for the acquisition -------------*/
handleErr(niScope_SampleRate (vi, &actualSampleRate));

/*- Display the actual sample rate on the GUI */
SetCtrlVal (guiHandle, GUI_actualSampleRate, actualSampleRate);


/*- Plot the data on the GUI graphs --*/
DeleteGraphPlot (guiHandle, GUI_acquisitionGraph1, -1, VAL_DELAYED_DRAW);

DeleteGraphPlot (guiHandle, GUI_acquisitionGraph2, -1, VAL_DELAYED_DRAW);

PlotWaveform (guiHandle, GUI_acquisitionGraph1, waveform, actualRecordLength,

VAL_DOUBLE, 1.0, 0.0, initialX[0], xIncrement[0], VAL_THIN_LINE,
VAL_SIMPLE_DOT, VAL_SOLID, 1, VAL_MAGENTA);


Here I want to modify this grapf whith a FFT function .... :


PlotWaveform (guiHandle, GUI_acquisitionGraph2, (waveform + actualRecordLength),
actualRecordLength, VAL_DOUBLE, 1.0, 0.0, initialX[1], xIncrement[1],
VAL_THIN_LINE, VAL_SIMPLE_DOT, VAL_SOLID, 1, VAL_YELLOW);

[Jeremiah Cox]

Hello Pad,
Let me make some recommendations to get you started. First, open CVI and go to Library >> Advanced Analysis >> Signal Processing and look through all the functions listed here. These are the functions for performing frequency analysis, windowing, and applying software filters to incoming data. Next, I would recommend looking at the example programs located at \samples\analysis\ and \samples\apps\spectrum\. These example programs show how to use many of the signal processing (frequency analysis, filtering, curve fitting, etc.) functions. If you have further questions, please feel free to post them here.

Jeremiah Cox
National Instruments
http://www.ni.com/ask