Basic Examples 
(2)
 

Numerical Fourier transform for a box function:
In[66]:=
f[t_]:=UnitStep[1-t]UnitStep[t+1]
In[67]:=
Plot
[◼]
NFourierTransform
[f[t],t,ω],{ω,-20,20},PlotRangeAll
Out[67]=
Compare with the answer from symbolic evaluation:
In[68]:=
[◼]
NFourierTransform
[f[t],t,0.7]
Out[68]=
0.734302
In[69]:=
FourierTransform[f[t],t,ω]
Out[69]=
2
π
Sin[ω]
ω
In[70]:=
%/.{ω0.7}
Out[70]=
0.734302