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Re: FourierTransform of Sinc Function

• To: mathgroup at smc.vnet.net
• Subject: [mg44393] Re: FourierTransform of Sinc Function
• From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
• Date: Sat, 8 Nov 2003 04:50:38 -0500 (EST)
• Organization: Universitaet Leipzig
• References: <200310281053.FAA25777@smc.vnet.net> <bo7of6$ag8$1@smc.vnet.net> <200311051500.KAA26329@smc.vnet.net> <bofrs7$5gt$1@smc.vnet.net>
• Reply-to: kuska at informatik.uni-leipzig.de
• Sender: owner-wri-mathgroup at wolfram.com

Hi,

you should read a book about singnal procesing to 
understand the difference of a discrete signal and
and continuous function.

You will never get a top-head function, you many
only get better discrete approximations to a top-head
function.

Regards
  Jens

Kieng wrote:
> 
> I am sorry my question is apparently not so clear.
> I generated a list of data from a sinc function.  I am not doing the
> transform from the sinc function.
> If I use Fourier[list of the data], and plot the result, her is where I am
> kind of not sure why I don't get a top hat function, even though I used very
> fine step for my sinc function data.
> 
> ----- Original Message -----
> From: "Jens-Peer Kuska" <kuska at informatik.uni-leipzig.de>
To: mathgroup at smc.vnet.net
> Subject: [mg44393]  Re: FourierTransform of Sinc Function
> 
> > Hi,
> >
> > what is mysterious on
> >
> > In[]:=FourierTransform[Sin[w*x]/x, x, k]
> >
> > Out[]=(Sqrt[Pi/2]*(-Sign[k - w] + Sign[k + w]))/2
> >
> > Regards
> >   Jens
> >
> > Kieng wrote:
> > >
> > > Dear All,
> > >
> > >  I tested the Fourier Function on a sinc function which should give the
> > > top-hat but mathatmatica gave some mysterious plot that I don't
> understand.
> > > Anyone knows what is going on.
> > >
> > > Thank you very much,
> > > Sorasak
> >

• References:
  • Re: FourierTransform of Sinc Function
    • From: Jens-Peer Kuska <kuska@informatik.uni-leipzig.de>