Sampling and Aliasing, Part 4
This workbook shows the result in the frequency domain of sampling a voice signal either with or without an anti-alising filter. The reconstructed signal contains not only the original signal, but also aliases of the original signal both above and below multiples of the sampling frequency. We can use a low pass reconstruction filter to eliminate the aliases as long as we sample fast enough that the nearest alias does not fold into or below the frequency of the original signal. If we band limit the original signal with an anti-aliasing filter, we reduce the bandwith and storage requirements of our system.