1 Oct
2010
1 Oct
'10
3:01 a.m.
On Sep 30, 2010, at 11:16 PM, fons(a)kokkinizita.net wrote:
Even windows won't save you from apparent madness. Imagine a signal
consisting of all zero samples, except one every second which has
value 1. Such a signal contains all frequencies that are a multiple
of 1 Hz, up to half the sample frequency. Those frequencies are present
all the time. Now take a window of say half a second. If it includes a
pulse you get more or less the same spectrum again. If it doesn't, you
get nothing... even if the frequencies should be there :-)
to come back to the beginning: that's why paulstretch does allow to specify the window
size.
Cheers!
robin
On Thu, Sep 30, 2010 at 09:23:08PM +0200, Robin Gareus
wrote:
I know the latter of course, but I've not yet been to the Musee des Arts et Metiers.
Thanks for the hint, I'll definitely schedule a visit.
There's so many hidden treasures here in plain sight one hardly knows where to start.
Back when I was introduced to FT in some Physics
lecture I was happy
that I was able to use it and completely forgot to check the history :)
Probably related to why I favored experimental Physics over Theory.
If you're still living in Paris, make sure to visit the 'Musée des
Arts et Métiers' one day. Quite a nice place for vintage experimental
physics. It's also the place where the final mad scene of Umberto Eco's
novel "Foucault's Pendulum" is situated. The pendulum itself used to be
there, but it's now at the Panthéon.
And I guess this is where the windowing comes in.
Calculate the spectrum
of small pieces instead.
correct.
Furthermore there are different kind of windows (here a window refers to
a block of audio-samples) and windows can overlap. That's where it gets
complicated. Ciao,
--
FA
There are three of them, and Alleline.