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fft in labview

Hi, all,

From my understanding about fft, the number of the output of the fft should be the same as the number of the input, but labview fft function cut it by half. Why? Thanks

Wu
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What specific FFT VI are you using? My guess is that you are using "Amplitude and Phase Spectrum.vi", which first computes the FFT using "FFT.vi" (which gives a full, two-sided spectrum as expected), then converts it to a one-sided spectrum. At any rate, I think you'll find that "FFT.vi" gives n output points for n input points. I've attahced a few screenshots: FP and BD for a simple VI that demonstrates that "FFT.vi" gives n outputs for n inputs and that "Amplitude and Phase Spectrum.vi" gives n/2 outputs for n inputs. Also in the screenshot image is the BD for "Amplitude and Phase Spectrum.vi" to show their approach for giving n/2 output samples.
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