A Guide on Spectral Methods Applied to Discrete Data in One Dimension

Figure 19

DFT with periodic spectrum. The dimensionless frequency axis ranges from to whereas its resolution is determined by the length of the total data set . It follows that the Nyquist frequency can be found at . In case that , which is equal to , the spectrum repeats. At , the plot indicates the mean value of the analyzed data. An arbitrary higher frequency component is indicated at