From Friday, April 19th (11:00 PM CDT) through Saturday, April 20th (2:00 PM CDT), 2024, ni.com will undergo system upgrades that may result in temporary service interruption.

We appreciate your patience as we improve our online experience.

LabVIEW

cancel
Showing results for 
Search instead for 
Did you mean: 

FFT input not accepted

Hello,

 

I have a program working that receives a byte stream and plots specific data from the stream in the time domain.  I would like that same data input into an FFT, however, my Spectral Measurement does not accept the data (ie. the wire is broken when connected).


Do I need to typecast this with something?  What am I doing wrong?

I have attached an image of my block diagram.

Thanks for any help.

 

 

0 Kudos
Message 1 of 6
(1,178 Views)

Your wire is broken because it doesn't even reach the wire.  You also have some other missing wires in that VI.

 

But you can't do an FFT on a scalar value.  You can only do FFT's on waveforms or arrays of data.

0 Kudos
Message 2 of 6
(1,146 Views)

Thanks for the response.  The wire obviously didn't reach where I was putting it but I was just trying to show where I was trying to connect...

 

Are you saying if I place the scalar data into a larger array, then I can take the FFT of the array?

Thanks again.

0 Kudos
Message 3 of 6
(1,142 Views)

Yes.  You need an array of data where each element was taken at a specified interval of time.

0 Kudos
Message 4 of 6
(1,128 Views)

It seems obvious to me that you need significantly more training and help.

 

You can do FFT on a scalar input by using FFT ptbypt. Is the time spacing regular and known?

 

(Why are you prepending instead of appending the blue array and why is the shift register uninitialized. Etc. Etc...)

0 Kudos
Message 5 of 6
(1,122 Views)

yeah, I'm new to this... the timing is known yes, thanks for the input.

0 Kudos
Message 6 of 6
(1,118 Views)