We have seen how by sampling a
Band-limited signal at a rate greater than twice the bandwidth
of the signal, it is possible to reconstruct the original
signal. But what happens if the sampling rate is less than (or
equal to) twice the bandwidth of the band-limited signal?
The different translated versions
of the original spectrum overlap in the spectrum of the
sampled signal. This effect is
called aliasing. If we attempt to reconstruct the original
signal using a low-pass filter, we might get a signal
completely different from the original signal. Lets take an
example.
