Re: Re: FourierTransform of Sinc Function

*To*: mathgroup at smc.vnet.net*Subject*: [mg44413] Re: Re: FourierTransform of Sinc Function*From*: "Steve Luttrell" <luttrell at _removemefirst_westmal.demon.co.uk>*Date*: Sat, 8 Nov 2003 04:50:55 -0500 (EST)*References*: <200310281053.FAA25777@smc.vnet.net> <bo7of6$ag8$1@smc.vnet.net> <200311051500.KAA26329@smc.vnet.net> <bofrs7$5gt$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

The top hat is centred on zero frequency. The default behaviour of Fourier is for the zero freqency bin to be the first element of the list, so when you plot this out the top hat is split between the left and right hand ends of the graph. -- Steve Luttrell West Malvern, UK "Kieng" <Sorasak at brown.edu> wrote in message news:bofrs7$5gt$1 at smc.vnet.net... > 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: [mg44413] 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>