1.1 Analog or Digital?

Even without defining information formally, we intuitively understand that speech, audio, and video signals contain information. We use the term message signals for such signals, since these are the messages we wish to convey over a communication system. In their original formboth during generation and consumption–these message signals are analog: they are continuoutime signals, with the signal values also lying in a continuum. When someone plays the violinan analog acoustic signal is generated (often translated to an analog electrical signal using microphone). Even when this music is recorded onto a digital storage medium such as a CD (usinthe digital communication framework outlined in Section 1.1.2), when we ultimately listen to thCD being played on an audio system, we hear an analog acoustic signal. The transmitted signacorresponding to physical communication media are also analog. For example, in both wireleand optical communication, we employ electromagnetic waves, which correspond to continuoutime electric and magnetic fields taking values in a continuum.

While the word “digital” has come to connote electronic in modern usage, its broader sense is best understood in contrast to “analog.” Whereas analog is continuous, digital is discontinuous. Analog is a spectrum — a blend, a bridge, between this and that. Digital is on or off, black or white, and zero or one.

It is in this broader sense that language connects us to both analog and digital realms.

Working with electronics means dealing with both analog and digital signals, inputs and outputs. Our electronics projects have to interact with the real, analog world in some way, but most of our microprocessors, computers, and logic units are purely digital components. These two types of signals are like different electronic languages; some electronics components are bi-lingual, others can only understand and speak one of the two.

In this tutorial, we'll cover the basics of both digital and analog signals, including examples of each. We'll also talk about analog and digital circuits, and components.

References:

Gideon. (13 de 09 de 2017). the-vital-edge. Obtenido de the-vital-edge: https://www.the-vital-edge.com/words-as-bridge/