In this chapter we group together some further questions and potential pitfalls that may await the unaware DFT users, but which do not fit into any of the previous chapters. In Sec. 8.2 we discuss the representation of discontinuities in the discrete world, in the input and output arrays of the DFT. In Sec. 8.3 we briefly review issues and artifacts that are related to the phase when using the polar (i.e. magnitude and phase) representation of the complex-valued spectrum. Then, in Sec. 8.4 we discuss symmetry related issues and the DFT artifacts that may result thereof. In Sec. 8.5 and 8.6 we discuss two artifacts that may occur due to sampling and reconstruction of continuous-world signals, namely, jaggies and sub-Nyquist artifacts, respectively. These two discrete-world artifacts are not specific to DFT, but they do occur in DFT applications, too, and we seize the opportunity offered by their explanation here to illustrate some questions related to DFT spectra and their continuous-world counterparts. Then, in Sec. 8.7 we review the main displaying considerations that should be taken into account in order to obtain a correct graphic representation of the DFT results, and finally in Sec. 8.8 we review very briefly some numeric precision considerations.
KeywordsConvolution Aliasing Undersampling
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