Suggestion for tapered sinc

"spasmous" <spasmous@yahoo.com> wrote in message
news:2f066762.0401111218.78f9e69e@posting.google.com...
> robert bristow-johnson <rbj@surfglobal.net> wrote in message
news:<BC26579A.7998%rbj@surfglobal.net>...
> > >>
> > >> maybe use a Kaiser window?
> > >
> > > OK. Any reason?
> > >
> > > I just read somewhere that Hamming is supposed to give the smallest
> > > side lobes, so I was thinking of using that.
> >
> > Hamming is easier to calculate (so it might be okay).  Kaiser is much
more
> > optimizes and has a control parameter to trade off main lobe width with
> > stopband attenuation.  you will probably need MATLAB or some good C math
> > library to compute the Kaiser window.
>
> I don't think additional control parameters are very helpful are they?
> It's just one more variable to have to optimise - so far I have window
> width as a variable, now I have to select a windowing function, then a
> parameter for the windowing function. Much better to have less
> variables, no? Hamming at least has some optimal property (minimises
> lobes) rather than just being an arbitrary choice out of all possible
> functions/parameters.
>
> I'd be interested in comments (nice ones, please)! :>

Not every design has the same goal--you may want minimal side lobes, but
someone else may want wider main lobe, etc..  The nice thing about the
Kaiser is that you can make it look like many of the other windows out there
just by changing the single parameter.  Then you don't have to search
between the myriad of other windows out there to get what you're looking
for--just pick Kaiser and tune it to your needs.  To many, this simplifies
things.

However, if there is a simpler window out there that already meets your
requirements, by all means use it and be happy!

Regarding "Much better to have less variables, no?" that depends on if your
goal is simplicity or fine control/optimization.  For many people, it is the
latter.

Nice enough for you?

-Jon