Reply by Vladimir Vassilevsky●February 1, 20102010-02-01
>>Sorry about that. Can you tell us the advantage of the Kaiser window
>>over the Kaiser-Bessel window?
> Well, I have no idea what is the difference between "Kaiser",
> "Kaiser-Bessel", or "Kaiser-Bessel derived" window. I am totally confused.
> But I found in few papers, that "Kaiser-Bessel derived" window is commonly
> used in Advanced Audio Coding (AAC) codec.
> Is there someone, who is clear in this topic?
The picture referenced above shows some (relatively) strange-looking
windows; one looks like a gothic arch, the others with increasing
amounts of flat-topness. That is definitely different from a "classic"
Kaiser window which with the right param can be made to closely
approximate Hann, Gaussian, etc.
Reply by Rune Allnor●February 1, 20102010-02-01
On 1 Feb, 12:41, "Afinko" <afi...@gmail.com> wrote:
> I am trying to use Kaiser-Bessel window before FFT.
> However, I am a bit confused about what is the difference between Kaiser
> and Kaiser-Bessel window.
Unless somebody comes up with very compelling arguments to
do otherwise, I'd interpret 'Kaiser-Bessel' the same way
as 'Dolph-Chebychev': Kaiser used Bessel functions to design
his window just the same way Dolph used Chebychev polynomials
to design his.
Reply by Afinko●February 1, 20102010-02-01
>Sorry about that. Can you tell us the advantage of the Kaiser window
>over the Kaiser-Bessel window?
Well, I have no idea what is the difference between "Kaiser",
"Kaiser-Bessel", or "Kaiser-Bessel derived" window. I am totally confused.
But I found in few papers, that "Kaiser-Bessel derived" window is commonly
used in Advanced Audio Coding (AAC) codec.
Is there someone, who is clear in this topic?
I'm a bit rusty on this, but IIRC, the terms "Kaiser window" and
"Kaiser-Bessel" window are nearly synonymous. I believe this original
Kaiser window was basically a Kaiser-Bessel window with some particular
parameter. Therefore, for systems like ScopeDSP, ScopeFIR, and Matlab
that provide a Kaiser-Bessel window, there isn't any real need for a
"Kaiser" window: just use the appropriate parameter to get that if you
really want it.
For brevity, Matlab calls their Kaiser-Bessel window function "kaiser".
However, in ScopeDSP and ScopeFIR, the term "Kaiser-Bessel" is used;
no "Kaiser" window is provided. (As Parks-McClellan bufs can attest,
the Matlab folks have been known to be rather sloppy with terminology. ;-)
BTW, if you use 4.0 for the alpha parameter of the Kaiser-Bessel window,
you get something that's very similar to the famous 4-point
The canonical definitions of data windows are given in the classic paper
"On the Use of Windows for Harmonic Analysis with the Discrete Fourier
Transform", by Fredric J. Harris, Proceedings of the IEEE, Vol 66, No.
1, January 1978. I think that paper has been updated, though I don't
have the reference handy for the update - I'm sure someone else here does.
Grant R. Griffin
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