matlab impulse train
>> freq = fft(impulseTrain, Len);
>> stem([(0:Len-1)/(Len*Ts)], abs(freq))
it shows a peak at 0 frequency, that result is correct.
what happens is the fft just gives u the first window, its made to give only the non repeating part...
actually every discrete signal is a periodic in frequency domain.
so the actual fft that u obtained(which is a spike delta function),,, repeat it to get ur actual frequency domain(which is a impulse train again, repeated impulses, coz FD is periodic)
mon