making my real set of data complex by adding an imaginary part
equal to zero.
Not sure why you're doing that instead of usinig REAL FFT and INVERSE
REAL FFT.
Are you sure you're generating the imaginary array the same length as
the real array?
That solved the problem. It was just a coincidences that the number of
data points was a prime. Adding another data point resolved the
problem.
Thanks
I just ran your problem waveform through REAL FFT and INVERSE REAL
FFT, subtracted the difference and got an error of 7 e-11 on the DC
term, and all other errors are on the order of e-14.
LabVIEW 7 Mac OS X
You are right, there is a problem. The problem is caused by a bug in
the FFT VI in LabVIEW 6.1. It does not compute correctly when the
number of input samples is a "big" prime number (in your case 59981
samples).
The work around is to add a "dummy" sample at the end of your time
signal before you
I am using LabVIEW6.1 and making my real set of data complex by adding
an imaginary part equal to zero. This works for every other sample
waveform I have tested. I.e Take the data, make it complex, perform
FFT and then perform IFFT. The waveform at the end is the same as the
start. Which is why I b
The IFFT in LabVIEW 7.0 requires you to enter the complete complex
input array, that is also including the complex conjugate "mirrored"
array. Earlier versions of LabVIEW were assuming your array to be
complex conjugated so this was optional.
So if you want your N samples to be real, you have to m
I am using Fourier Transforms to filter a signal I have. I noticed
that for one perticular waveform the waveform returned after the
inverse transform was performed was messed up. In the course of
finding the problem I step up the filter so it would not filter the
signal at all. The waveform returne
