Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
2007
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 2007

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: FFT of the piecewise step function

  • To: mathgroup at smc.vnet.net
  • Subject: [mg77792] Re: [mg77769] FFT of the piecewise step function
  • From: Sseziwa Mukasa <mukasa at jeol.com>
  • Date: Sun, 17 Jun 2007 05:58:44 -0400 (EDT)
  • References: <200706160732.DAA25970@smc.vnet.net>

On Jun 16, 2007, at 3:32 AM, Peng Yu wrote:

> Hi,
>
> mask[x_] := UnitStep[-(x - 1/2)(x + 1/2)(x - 3/2)(x + 3/2)]
> freq[=F9_] := FourierTransform[mask[t], t, =F9]
>
> The solution of freq includes several DiracDelta functions, which
> should cancel out.
>
> I'm wondering if there is anyway to make mathematica cancel them out.

In this particular case it's easier to just use Integrate explicitly:

In[9]:= Simplify[Integrate[Exp[-2 Pi I w t],{t,1/2,3/2}]+Integrate[Exp=

[-2 Pi I w t],{t,-3/2,-1/2}]]
Out[9]= (E^(-2 I Pi w) (1+E^(4 I Pi w)) Sin[Pi w])/(Pi w)

Regards,

Ssezi=


  • Prev by Date: Re: Re: Re: Fast interactive graphics
  • Next by Date: Re: FFT of the piecewise step function
  • Previous by thread: FFT of the piecewise step function
  • Next by thread: Re: FFT of the piecewise step function