Thread Subject: Nonlinear fourier transform

Hi all!
I want to fourier transform some discrete data (vectors of size 1x32). The problem is that the assosciated time vector (data acquisition times) is not linear, i.e. evenly spaced in time. This prevents me from using FFT in Matlab (I think!)... Is there another way to transform the data into frequency space in Matlab?
Thanks!
/Ida

You can use interpolation of your data from nonlinear spreaded times
to linear spreaded times. See interp1 function. And then make fft.

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Quaternions visualizations in Matlab:
http://quaternion.110mb.com/

http://www-user.tu-chemnitz.de/~potts/nfft/

Bruno

"Ida Haggstrom" <ida_haggstrom@yahoo.se> wrote in message <gkhvtl$2lj$1@fred.mathworks.com>...
> Hi all!
> I want to fourier transform some discrete data (vectors of size 1x32). The problem is that the assosciated time vector (data acquisition times) is not linear, i.e. evenly spaced in time. This prevents me from using FFT in Matlab (I think!)... Is there another way to transform the data into frequency space in Matlab?
> Thanks!
> /Ida

http://people.ee.duke.edu/~qhliu/Presentations/NUFFT_UMD_2004.pdf