ABSTRACT
In this chapter we demonstrate how the problem of Fourier-transform estimation from sampled data arises in the processing of measurements obtained by sampling electromagnetic-or acoustic-field fluctuations, as in radar or sonar. We continue the discussion, begun in Chapter 9, of planewave solutions of the wave equation. To illustrate the use of non-plane-wave solutions we consider the problem of detecting a source of acoustic energy in a shallow-water environment.
