Re: discuss [bug #43305] Hamming etc. windows are wrong

[Doug Stewart]

On Tue, Dec 30, 2014 at 12:48 PM, Doug Stewart <address@hidden> wrote:

Rik asked me to start a discussion here about how to fix this bug.

 The real question is:   Should we do as Matlab did or should we make the default  

 be the more mathematically correct method.

 I am arguing for the mathematically correct method as the default.

 ( I will be happy even if I loose  the argument)

I will post my argument in the next chapter :-)

Comment are welcome.

 The technical reason that our window functions are wrong was

 given by the original poster, Oscar Ruitt.

  The Wikipedia page  down at

       Filter design:

       http://en.wikipedia.org/wiki/Window_function

 Shows 3 different methods 

   -- Matlab symmetric

   -- Matlab Periodic

   -- DFT-even

 DFT-even is what I have been thinking as the "correct" 

 way to go.

  I dont have Matlab so, would someone run

 hann(8) on matlab and see if the first number is non zero?

Octave gives

hann(8)

ans =

   0.00000

   0.18826

   0.61126

   0.95048

   0.95048

   0.61126

   0.18826

   0.00000