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<font face="Courier New">Samuel,<br>
<br>
Like it or not, I guess these keywords come from Matlab, and as
Matlab still seems to dominate the market, many people, including
those willing to quit Matlab (as I did several years ago), are
quite used to those keywords. Other software such as Octave and
scipy.signal (Python) adhere to this style, so it is already sort
of a standard. "Open" and "closed" might have been an option when
there was still no name for the concept, but now it doesn't seem
advisable.<br>
<br>
That some name be intuitive or not may depend on the circumstances
one was exposed to that name. I myself find it intuitive enough,
or at least not counterintuitive.<br>
<br>
I'm not sure whether it is correct to say that the generated
window is both symmetric and periodic. Probably it is either
symmetric or asymmetric, but never periodic per se, since it
doesn't repeat itself. It tacitly becomes periodic when used along
with an FFT, but just because the FFT assumes a periodic model of
the signal, so what "periodic" means is just that its "natural"
period is equal to its length. But even this can be challenged:
What is the "natural" period of a function? I guess this makes
sense mainly in the case of windows that are derived from cosines,
such as many of the most successful windows (e.g. Hann, Blackman,
Blackman-Harris and several flat-tops) <br>
<br>
Regards,<br>
<br>
Federico<br>
<br>
<br>
</font><br>
<div class="moz-cite-prefix">On 09/04/2021 15:29, Samuel Gougeon
wrote:<br>
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<div class="moz-cite-prefix">Dear Federico,<br>
<br>
Thank you for the proposal.<br>
I am afraid that the "symmetric" and "periodic" flag names are
not intuitive to me.<br>
Indeed, the generated window is <i>always</i> both periodic and
symmetric. It is anyway "algorithmically seen" as periodic (from
a spectral point of view), since it is regularly sampled, while
regular-sampling and periodicity are FT-dual.<br>
<br>
The point is that it is either <b>open</b>, or <b>closed</b>
(what is rather expected, for a window. Sorry for the (serious)
joke :-), with a closing point at the same level as the opening
one.<br>
<br>
I know from where these "symmetric" and "periodic" keyworks come
from.<br>
But, sorry, i can't resolve myself blindly copy others without
discussion. Badly naming things usually become
counterproductive, noticeably when teaching (here signal
processing).<br>
<br>
For contribution,<br>
<br>
Best regards<br>
Samuel<br>
<br>
<br>
</div>
<div class="moz-cite-prefix">Le 11/02/2021 à 08:12, Federico
Miyara a écrit :<br>
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<font face="Courier New">Dear All,<br>
<br>
I wonder why windowing functions such as Hann, Hamming, etc.,
provided by window(), are only symmetric.<br>
<br>
When used for spectral analysis by subsequent use of fft(),
the periodic weighting is better than the symmetric one. The
symmetric window is mainly used in the design of FIR filters,
which I guess is a less frequent application than spectral
analysis.<br>
<br>
While it is true that an easy workaround to get a periodic
window of length n is, for instance<br>
<br>
w = </font><font face="Courier New">window("hn", n+1)(1:$-1);
<br>
<br>
</font><font face="Courier New">a syntax such as this <br>
<br>
w = </font><font face="Courier New">window("hn", n, "per"); <br>
<br>
</font><font face="Courier New">would be easier.</font><font
face="Courier New"> Setting "sym" as the default option, no
backward compatibility issues would possibly arise.<br>
<br>
Regards,<br>
<br>
Federico Miyara<br>
</font>
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