Hello Rafael,
Le 07/06/2018 à 15:04, Rafael Guerra a écrit :
Hi Samuel,
Fyi, many DFT references recommend averaging the values at endpoints
and discontinuities in general. See for instance:
Briggs, W. L. and V. E. Henson [1005] The DFT: an owner's manual for
the Discrete Fourier Transform, SIAM, Philadelphia.
>and discontinuities in general
Yes, that's a point. If a specific processing is used for the edges, it
would look strange to not implement it as well in the body of the
initial signal. From here, a criteria (and likely some threshold) must
be set to decide what's a discontinuity, and what's not.
I did not go into any reading -- and frankly, if there is a summarized
performances comparison and a standard published procedure --, it would
be easier just to implement it, instead of reinventing the wheel with
external tests. Then, i am afraid that it will come either with some
choices with respect to the type of input signal, or with a bunch of
processing options (making circshift a signal processing function rather
than just a general matrix handling operation).
Anyway, no damping window could process inner discontinuities.
To me, the main advantage of the DFT was to avoid local interpolations,
in order to stay simple.
If the algo then implements some interpolations, why not performing the
fractional part of the shift
only by interpolation, instead of /in addition/ to the DFT?
If you can provide some quantified rationale and possibly some finalized
algo, it would be fine.
Best regards
Samuel
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