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On 04.11.2010 16:14, Mathieu Bouchard wrote:
<blockquote
cite="mid:alpine.DEB.2.00.1011041109210.6119@paik.artengine.ca"
type="cite">On Thu, 4 Nov 2010, Martin Schied wrote:
<br>
<br>
<blockquote type="cite"> Hi everyone,
<br>
i wondered if someone made a patch measuring the PHASE of
a reference signal compared to measured signal
<br>
<br>
you could one of the cross-correlation externals to measure the
time delay between 2 signals. (there's one external in iem_tab
from pd-extended I remember and there are possibly more). If
that's useful for you I created a similar, fft based patch using
vanilla objects I can post here. However correlation doesn't
directly measure phase differences of separate frequency bands
but the delay of the signal over all frequencies.
<br>
</blockquote>
<br>
What do you mean ? If you get the imaginary part of the logarithm
of the cross correlation, it gives you a list of phase differences
corresponding to each frequency bin, right ?
<br>
</blockquote>
if your's still in the frequency domain you can do such things, but
the iem_tab external output is already time domain - also I'm no
math guru so you definitely answer this better...<br>
I took the math from
<a class="moz-txt-link-freetext" href="http://www.engr.udayton.edu/faculty/jloomis/ece561/notes/xcorr/xcorr.html">http://www.engr.udayton.edu/faculty/jloomis/ece561/notes/xcorr/xcorr.html</a>
which is offline now unfortunately, but the explanation was very
good. hope it comes back. ;)<br>
<blockquote
cite="mid:alpine.DEB.2.00.1011041109210.6119@paik.artengine.ca"
type="cite">
<br>
(that's equal to the atan2 between the real and imaginary parts of
the cross-correlation)<br>
</blockquote>
attached a correlation and a "phase difference" patch. it's very
basic and may contain errors ;)<br>
<br>
Martin<br>
<br>
<br>
<br>
<br>
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