Page 21 - Bebop to The Boolean Boogie An Unconventional Guide to Electronics Fundamentals, Components, and Processes

2 Chapterone

We can illustrate the differences in the way these two systems work by
means of a graph-like diagram (Figure 1-1). Time is considered to progress from
left to right, and the solid lines, which engineers often refer to as waveforms,
indicate what is happening.

%' 8;'
Digital Off On off

Figure 1-1. Digital versus analog waveforms

In this figure, the digital waveform commences in its OFF state, changes to

its ON state, and then returns to its OFF state. In the case of the analog wave-
form, however, we typically don't think in terms of ON and OFF. Rather, we
tend to regard things as being more OFF or more ON with an infinite number of

values between the two extremes.
One interesting point about digital systems is that
they can have more than two states. For example,
consider a fun-loving fool sliding down a ramp
mounted alongside a staircase (Figure 1-2).
In order to accurately determine this

person's position on the ramp, an indepen-
dent observer would require the use of a tape
measure. Alternatively, the observer could

estimate the ramp-slider's approximate
location in relation to the nearest stair.
The exact position on the ramp, as measured

using the tape measure, would be considered
to be an analog value. In this case, the
analog value most closely represents the real

Figure 1-2. Staircase and ramp world and can be as precise as the measuring