[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Fourier decomposition

On 16 Sep 2005 at 19:20, Fred Herzfeld wrote:

> Hello List:
> I am now about to make public some work on signal decomposition. As part 
> of the disclosure I will make the statement:
> ------------------
> It is not possible to accurately recover the coefficients (amplitude and 
> phase of the individual harmonics) of a function consisting of harmonic 
> sinusoidal components, when the Period of the not necessarily present 
> fundamental is not known, by using the normal computational procedure of 
> either the Fourier Series or the Short term Fourier Transform.
> -----------------------
> I would appreciate any and all comments.

Interesting question.  Pre-multiplication by ordinary windowing
functions seems to do a pretty good job when recovering the
magnitudes, but I've never looked into what this does to the
phase.  I gather from your statement that it screws it up, and
that there is no analogous window function for obtaining phase?

Thanks for your insights...

Bob Masta