From octave-sources-request at bevo dot che dot wisc dot edu  Tue May 28 14:21:50 2002
Subject: Dolph-Chebyshev Window
From: =?iso-8859-1?q?Andr=E9=20Carezia?= <acarezia at uol dot com dot br>
To: octave-sources at bevo dot che dot wisc dot edu
Cc: Max Gerken <mgk at lcs dot poli dot usp dot br>
Date: Tue, 28 May 2002 14:44:48 -0300


--------------Boundary-00=_OA1UBFZ2JETZ8XLN7C2W
Content-Type: text/plain;
  charset="iso-8859-1"
Content-Transfer-Encoding: 8bit

Hello,

I needed a Dolph-Chebyshev window for a signal processing research. As 
I have not found it in Octave (and it is *not* in octave-forge), I 
wrote one based on the article below:

  <http://www.maths.tcd.ie/~plynch/Publications/Dolph.pdf>

which is based on the classic paper by Dolph (1946).

Note that I *have* tried to implement the window according to the (also 
classic) F. Harris (1978) paper but I concluded he left some mistakes 
in the definition I found there.

This one is defined in the frequency domain, and converted back to time 
domain by means of a Fourier transform. I have also tried to implement 
the time domain versions I found in the Mitra publications:

  <http://www.ece.ucsb.edu/courses/ECE258/258A_W02Mitra/Ch7(3).pdf>

and in the documentation of ISIP:

  <http://www.isip.msstate.edu/projects/speech/software/documentation/class/algo/Window>

but the definitions are either wrong or present numerical problems. 
Please, feel free to comment on the above digression :-)

Attached are two files:

  chebwin.m: Coefficients of the Dolph-Chebyshev window
  cheb.m:    Value of the Chebyshev polynomials (used by chebwin.m)

I tested it with Octave 2.1.35, official Debian package (woody), for 
windows ranging from 5 points to 251 points, and for attenuation 
ranging from 20 dB to 140 dB. I believe it is correct.

Regards,

-- 
André Carezia
http://sites.uol.com.br/acarezia










--------------Boundary-00=_OA1UBFZ2JETZ8XLN7C2W
Content-Type: text/plain;
  charset="iso-8859-1";
  name="chebwin.m"
Content-Transfer-Encoding: base64
Content-Disposition: attachment; filename="chebwin.m"
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--------------Boundary-00=_OA1UBFZ2JETZ8XLN7C2W
Content-Type: text/plain;
  charset="iso-8859-1";
  name="cheb.m"
Content-Transfer-Encoding: base64
Content-Disposition: attachment; filename="cheb.m"
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=

--------------Boundary-00=_OA1UBFZ2JETZ8XLN7C2W--