Feature - On the roots of digital signal processing - Part II

Part I of this article dealt with the mathematical methodology of antiquity which was essentially of a discrete character whereby a circle was deemed to be a multi-sided polygon whose perimeter or area could be more easily deduced by considering the multi-sided polygon to be made up of a finite set of elemental triangles. Then the emergence of numerical methods during the 1700s as a tool for interpolating numerical data was explored. Part II deals with certain spectacular mathematical discoveries made in France just before, during, and after the French Revolution by Laplace, Fourier, Poisson, and Laurent, which form the foundation of modern spectral analysis. Then the contributions of Nyquist and Shannon to the sampling theorem are examined. The article also reviews the work of Babbage from the perspective of a DSP practitioner and examines the historical circumstances that eventually led to the invention of digital computers and their application as general-purpose inexpensive components in DSP systems. The article concludes with a summary of some of the innovations of the sixties that led to the emergence of what we now call digital signal processing.