Re: FFT of the piecewise step function

*To*: mathgroup at smc.vnet.net*Subject*: [mg77794] Re: FFT of the piecewise step function*From*: Bill Rowe <readnewsciv at sbcglobal.net>*Date*: Sun, 17 Jun 2007 05:59:45 -0400 (EDT)

On 6/16/07 at 3:32 AM, pengyu.ut at gmail.com (Peng Yu) wrote: >mask[x_] := UnitStep[-(x - 1/2)(x + 1/2)(x - 3/2)(x + 3/2)] >freq[=C3=B9_]:= FourierTransform[mask[t], t, =C3=B9] >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. You didn't say what version of Mathematica you are using. In version 6, I get the following: In[6]:= m = UnitStep[-(x - 1/2) (x + 1/2) (x - 3/2) (x + 3/2)]; =46ourierTransform[m, x, w] Out[7]= (Sqrt[2/Pi]*(Sin[(3*w)/2] - Sin[w/2]))/w In[8]:= $Version Out[8]= 6.0 for Mac OS X PowerPC (32-bit) (April 20, 2007) If you are not getting this, you might try using Simplify or FullSimplify -- To reply via email subtract one hundred and four

**Follow-Ups**:**Re: Re: FFT of the piecewise step function***From:*"Peng Yu" <pengyu.ut@gmail.com>