Radio and Television
Radio transmission and reception was perhaps one of the earliest applications of electronics, and is—so far—the application that has made the greatest impact on society. Oddly, we can use radio, predict its properties and design circuits that work very efficiently, but we know little about the real nature of radio. Ask an electronics engineer what radio is, and the answer will be a confident, ‘Electromagnetic waves.’ Ask a physicist what electromagnetic waves are, and he will begin to hedge, or he will tell you that really we don’t know. We do know that electromagnetic radiation is a form of energy, and that it behaves as if it is propagated as waves. The model becomes more of a model and less like reality when we discover that radio travels through a vacuum. How can there be waves in a vacuum? Perhaps in the future, theoretical physics will give us an answer. In the meantime, we use radio, describe it mathematically, and design and use electronic circuits that function happily despite our underlying ignorance.
Unable to display preview. Download preview PDF.