[Octave-bug-tracker] [bug #50820] [octave forge] (signal) pwelch incorrectly discards DC component

[John W. Eaton]

Follow-up Comment #15, bug #50820 (project octave):

Thanks for the update.

Doesn't fft(X,N) pad X with zeros as needed?  It seems easier to do that than
to insert X into a zero-padded XX array.  That's why I changed the call to use
fft(X,N).

Instead of generating a cell array of colons, you can use indexing like this:


x = reshape (1:60, [10,2,3])  ## 3d array for illustration.
xx = x(start:end,:)  ## all columns in all pages as a 2d array.
reshape (xx, [end-start+1,2,3])  ## IF you need 3d array again.


I was also confused by the subtraction of 3.  It was in the original pwelch.m
from Octave Forge.  Are there any cases where it is needed to avoid generating
a window size that is too large?

What should happen for short vectors?  Is there a minimum size limit that
should be enforced?


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