Page 22 - Bebop to The Boolean Boogie An Unconventional Guide to Electronics Fundamentals, Components, and Processes

Analog versus Digital 3

technique allows. By comparison, an estimation based on the nearest stair
would be considered to be a digital value. As was previously noted, a digital
value is represented as being in one of a finite number of discrete states. These
states are called quanta (from the Latin neuter of quantus, meaning “how great”)
and the accuracy, or resolution, of a digital value is dependent on the number
of quanta employed to represent it.
Assume that at some starting time we’ll call To (“time zero”), our thrill-
seeker is balanced at the top of the ramp preparing to take the plunge. He
commences sliding at time T, and reaches the bottom of the ramp at time T,.
Analog and digital waveforms can be plotted representing the location of
person on the ramp as a function of time (Figure 1-3).
Once again, the horizontal axis in
both waveforms represents the passage
Height
of time, which is considered to
progress from left to right. In the case
ANALOG VIEW
of the analog waveform, the vertical
axis is used to represent the thrill-
seeker’s exact location in terms of
- - -- I”__ -.
height above the ground, and is
-_^__^___
therefore annotated with real,
physical units. BY comparison, the
vertical axis for the digital waveform Ti
is annotated with abstract labels,
Nearest
which do not have any units associ- step
ated with them.
DIGITAL VIEW
To examine the differences be-
tween analog and digital views in
more detail, let’s consider a brick
suspended from a wooden beam by
a piece of elastic. If the brick is left I \ Time
to its own devices, it will eventually
reach a stable state in which the pull
of gravity is balanced by the tension Figure 1-3. Analog and digital waveforms
in the elastic (Figure 1-4). showing the position of the person
sliding down the ramp