Finding the fourier transform of a real time signal aquired using LIFA

[anupam2016]

Hello,

I am a newbie to LabView.I am working with a project  in which I have to aquire anlaog signal through the arduino and find  the frequencies in it so that proper hardware filters can be

constructed and used for increasing noise-signal ratio.

But  the problem I am facing when I keep the graph indicator in autoscale  settings is , I see rapid movement of the graph scale but zero output.

I wonder if I have done something wrong in connecting different blocks of fourier transfom in the VI.

I am attaching my VI.

Can you also suggest me if there is any other way to find frequencies in my input signal.

Thanks in advance

Anupam

[Nathan_B.]

You are trying to compute the FFT of a scalar value.  This is not possible.  You need use the FFT on a series of consecutive values that are sampled with the same timestep between each value.

Note that because of the slow rate of communication of serial devices like the Arduino you will not be able to sample very fast and there is no guarantee as to a consistent timestep between each sample.  What is the frequency range of your intended input signal?

And, as always, I highly recommend that you do NOT use LIFA.  LIFA has not been updated in several years and is no longer supported.  LINX has replaced LIFA and can be found at http://www.labviewmakerhub.com/linx (support is provided on the MakerHub forums).