Path: news.mathworks.com!newsfeed-00.mathworks.com!newsfeed2.dallas1.level3.net!news.level3.com!postnews.google.com!i36g2000prf.googlegroups.com!not-for-mail
From: dbd <dbd@ieee.org>
Newsgroups: comp.soft-sys.matlab
Subject: Re: how to reverse windowing effect?
Date: Tue, 20 May 2008 19:21:08 -0700 (PDT)
Organization: http://groups.google.com
Lines: 33
Message-ID: <1a47911b-bc58-4d56-998a-d92f91ef9514@i36g2000prf.googlegroups.com>
References: <g0t486$r84$1@fred.mathworks.com> <ce40645a-ff51-449e-9db0-9a3652651bae@u12g2000prd.googlegroups.com> 
NNTP-Posting-Host: 75.17.140.180
Mime-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
X-Trace: posting.google.com 1211336468 28791 127.0.0.1 (21 May 2008 02:21:08 GMT)
X-Complaints-To: groups-abuse@google.com
NNTP-Posting-Date: Wed, 21 May 2008 02:21:08 +0000 (UTC)
Complaints-To: groups-abuse@google.com
Injection-Info: i36g2000prf.googlegroups.com; posting-host=75.17.140.180; 
User-Agent: G2/1.0
X-HTTP-UserAgent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.1.14) 
Xref: news.mathworks.com comp.soft-sys.matlab:469579


On May 20, 3:33 pm, "ggk " <ggkm...@comcast.net> wrote:
> Dale, thanks... in your text

> "Nuttall calls it the minimum 4-term window. The
> coefficients are given in (37) on page 89."
>
> is (37) referencing a paper? Or is it just page 89 of the
> Nuttall paper I referenced above?

(37) is the equation number in the paper where the coefficient values
are given.

Of the dozens of windows Nuttall has described, this one is the one
that Matlab calls "nuttallwin" although there is no way to tell that
from the documentation without looking to see if the coefficients are
the same as in (37) on page 89 of the Nuttall paper. (They are.)

> Rune, thanks...

Windowing is still not always irreversible. As Rune points out,
windowing may not even be needed for what you say you want to achieve.

Go back to my original suggestion 5). You want to perform a transform-
modify-inverse-transform process. So do the audio compression people.
They compress and decompress as their 'modify' and apply windows
complementary and compatible with reconstruction. Your 'modify' seems
to be noise removal. Google on 'spectral subtraction' for an extensive
literature on that topic.

Good luck

Dale B. Dalrymple