Sampling and Aliasing, Part 3
- David Abrams
This workbook shows the result in the frequency domain of sampling a single 0.5Hz cosine signal. The reconstructed signal contains not only the original cosine, but also aliases of the original signal at multiples of the sampling frequency plus and minus 0.5Hz. 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. Vary the sampling rate to see where the aliases appear. Note that if the sampling rate is less than the Nyquist rate (2x the frequency of the 0.5Hz cosine) the reconstruction filter cannot remove it from the output.