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10/24/06 11:39am

Helloeverybody, I 've a general question on a DFT problem, solved with the Fourier[] command.

Given for example 32 data (real numbers) and asked the program to compute Fourier, I got 32 complex vector, and that is ok.
Actually 2 of these vectors are real, the other are 15 complex (and the relative conjugates). That is also ok.

Then, I want to 'translate' the complex in to 16 armonic functions, terms such as A*cos[freq*t+phase].
So I ask the program for the amplitudes (command Abs) and for the phase (command Arg) and combine them with the above written formula.

I know that the term relative to frequency =0 is the first one, then the problem is: the term relative to the first armonic I am considering (the one with lower frequency, Pi/16 in this case) is the second one or the last (in the vector of teh complex numbers)?
I have the feeling that mathematica is putting the vector in a wired order, also because doing the same stuff with other programs I got the same complex vectors, but in a different order.

Does any of you an idea of what is going on about it?


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Author Date Posted
Discrete Fouriere transform Edoardo 10/24/06 11:39am
Re: Discrete Fouriere transform yehuda ben-s... 10/26/06 01:45am
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