The Sampling Theorem and Aliasing
Having presented the mathematical model of the sampling process in the previous chapter, the practical implications and properties of the sampling process are discussed here. This includes the phenomenon of spectral periodicity, the dependence of the spectral periodicity on the sampling frequency, and the dependence of its shape on the time width of the sampler itself. The phenomenon of frequency aliasing is discussed, as well as methods of avoiding aliasing by formulating appropriate conditions on the sampling frequency. Graphical and simplified methods of illustrating the sampling process are provided, and numerous examples using those methods are given.