2) modulation, in communications. The Columbia Encyclopedia, Sixth Edition. 2001
...The original, unmodulated wave may be of any kind, such as sound or, most often, electromagnetic radiation, including optical waves. The carrier wave can be a direct...

3) television. The Columbia Encyclopedia, Sixth Edition. 2001
...Television has become a major industry, especially in the industrialized nations, and a major medium of communication and source of home entertainment. Television...