Essential Guide to Computing: The Story of Information Technology, The

Waves of Information

We have learned that computers represent information in the form of electrical pulses traveling through a wire—a voltage of a certain level or higher represents a one, anything lower represents a zero. This system has the virtue of simplicity, and because of that, accuracy. If the timing is right (and timing is always critical), the receiver doesn't have a difficult distinction to make—it is quite easy to distinguish a one from a zero because the voltages are very different (see Figure 10.1).

But there are other ways to use electricity, or its ally electromagnetism, to carry information. We can use waves instead of pulses. Electromagnetic waves occur naturally; the entire range, from radio waves to light rays to gamma rays, ...