Sampling of base band and band pass signals

Abstract

This chapter deals in complete detail with the first two steps involved in converting an analogue signal in to a sequence of binary numbers (called bit stream), specifically the processes of anti-alias filtering and sampling.The sampling theorem that governs distortion-free sampling can only be obeyed in strictly band limited signals that have no frequency components outside a bandwidth B. However, most naturally occurring analogue signals are not strictly band limited in the sense that they do contain stray frequency components outside the bandwidth B. In that case alias distortion is unavoidable and the design goal is to reduce this distortion to a negligible level in order to allow a signal of acceptable quality to be reconstructed from samples even when the original signal is not strictly band limited. This and other issues to do with the sampling of base band and band pass signals as well as measures to mitigate practical constraints and distortions have been discussed in full.