Digital Signal Processing, 10th Edition

Foreword (Historical Perspective)

The most important and most impactful technical revolutions are not always those that are most evident to a product’s end user. Modern digital signalprocessing methods fall into the category of impactful technical revolutions whose consequences are not immediately perceptible, and which do not make the front page.

It is interesting to reflect, for a moment, on the way in which such techniques emerge. Digital computation, applied to a signal in the broadest sense, is certainly not a new idea in itself. When Kepler derived the laws of motion of the planets from the series of observations made by his father-in-law Tycho Brahe, his was a truly numerical computation of the signal – in this case, the signal being Brahe’s observations of the planets’ positions over time. In recent decades, though, digital signal processing has become a discipline in its own right. What has changed is the way it can now process electrical signals in real time, using digital technologies.

This leap forward is the cumulative result of technical progress in numerous fields – starting, of course, with the capability of recording the data we wish to process in the form of an electrical signal. This has been contingent on the gradual development of what are known as information sensors, which can range in complexity from a simple stress gage (which, in itself, took a great deal of research in solid mechanics to make possible) to a radar system.

In addition, with the marvelous ...