ive been working on a release that contains this and some other fixes, which hopefully will be completed soon.

comment #1:

> Pushed to repo https://sourceforge.net/p/octave/signal/ci/e5e55abbc84a2bfeb5d27f88e14f845e8e23851b/

Hi, this has been in testing for months. I tested it and works perfectly fine for me, in case it helps.

Only one comment: line 558 should be changed from:

error( 'pwelch: arg %d (window) vector must be real and >=0',iarg+1);

to:

error( 'pwelch: arg %d (window) vector must be real',iarg+1);

Not sure how I can help to get this closed and merged. Please let me know.

Thanks,

The simple code below returns “error: pwelch: arg 2 (window) vector must be real and >=0”.

% create a simple signal
k = 1:128;
x = sin(2 * pi * k / 10);
% create the window function
win = flattopwin(128);
% calculate the spectrum with a flattop window
pwelch(x, win)

I can see in the pwelch.m file line 558 (https://sourceforge.net/p/octave/signal/ci/default/tree/inst/pwelch.m#l558) this condition is checked and enforced.
This is also consistent with pwelch's help:

 window
      [real vector] of window-function values between 0 and 1; the
      data segment has the same length as the window.  Default
      window shape is Hamming.

I agree the window must be a real vector, but why does it require to be >= 0? As far as I understand there is no mathematical reason for that requirement and, in fact, falttop windows have negative values.

This is an easy fix on line 557 and, of course, the documentation:

- elseif ( is_win>1 && ( ~isreal(arg) || any(arg<0) ) )
+ elseif ( is_win>1 && ( ~isreal(arg) ) )

Thanks,