Step function and complex FFT

[Bonhomme]

Hi there,

I have an array of values formed from a sin(x^2) wave. I'm trying to send the array through a complex FFT and supposedly come out with a step function. However, if you download the example, you will see that this is not the case. Does the complex FFT in LabVIEW take into account both the real and imaginary portions? Am I on the right track? Thanks.

-Mike

[JLewis]

Hi Mike,
Yes, the complex FFT takes into account both real and imaginary portions. The output of the FFT is a complex number, but the graph expects a DBL. Try inserting a Complex to Polar conversion between the FFT output and graph (from Numeric>>Complex palette). Wire up the "r" output and you should see something more like you expect.