Maximum FFT size?

[SteveW]

The CVI version 8 FFT function accepts an integer as an input size, thus inferring that a 2^32-bit FFT can be performed. Is this limit real? I have a customer that wants to perform an FFT on a data stream with about 8M samples. If this can actually be done, any ideas about how long it would take?

Thanks,

Steve

[Steak McDAX]

Hi Steve,

The FFT function's input is a 32-bit integer, meaning the max value would be 4,294,967,296.  So that would be your limit.  I hope that helps!

[SteveW]

Hi Matt,

Thank you for confirming that the function can indeed handle such long input streams. Do you have any idea how long an 8M FFT would take (i.e., seconds, minutes or hours)?

Steve

[Steak McDAX]

Hi Steve,

I tested out the FFT on my end with an 8 million sample array, and it took a few seconds.  I hope this helps!

[SteveW]

Matt,

Super, thanks. I was concerned that I was about to embark on an impractical task.

Steve