[Tutor] fourier transform
dyoo at hkn.eecs.berkeley.edu
Tue Aug 2 00:18:49 CEST 2005
On Mon, 1 Aug 2005, Jeff Peery wrote:
> thanks for the help. I think I'm understanding this a bit better.
> although I still don't completely understand the output. here is an
> example... for the input I have 1024 samples taken from a 1 Hz square
> wave with amplitude = 1. for the output I would expect an infinite
> number of frequencies. the output from FFT.fft(myData).real is this:
> I would expect 0.498 at all frequencies? why the oscillation?
That actually sounds fine. By a square wave, you mean something like:
------- ------- -------
| | | |
| | | |
and according to the MathWorld documentation that Christian mentioned,
according to analysis, the square wave does have a Fourier transform that
oscillates the way that you've observing:
where the coefficients are zero on the even n. So I think you're actually
getting correct values there.
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