Consider a signal x$($t$)$ with Fourier transform X$($j$).$ Let

c be the highest frequency component of X$($j$).$ In class we showed that a band$-$limited signal,

x$($t$),$ can be exactly reconstructed from its samples provided the sampling rate exceeds the $2$ c

$2$

samples$/$s$.$ For a baseband signal, x$($t$),$ if the sampling rate is less than this value, then aliasing

will occur, and it will not be possible to recover x$($t$)$ exactly from its samples.