In this chapter, we turn our attention to the issues in spectral estimation and FIR filter design. Quite often, the DFT is used as an approximation to the CTFT. However, we should be aware of the fact that there are several pitfalls associated with this approximation. The discrepancies between the DFT and the CTFT arise because DFT requires sampling and truncation. Improper sampling gives rise to “aliasing errors.” Aliasing refers to the distortion of the signal spectrum due to the introduction of spurious low-frequency components owing to a combination of a very low sampling rate and an improper anti-aliasing filter. Section 2.1 briefly describes sampling, reconstruction, and the associated ...
