Radio is the wireless transmission of signals through free space by electromagnetic radiation of a frequency significantly below that of visible light, in the radio frequency range, from about 30 kHz to 300 GHz. These waves are called radio waves. Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space.
Information, such as sound, is carried by systematically changing (modulating) some property of the radiated waves, such as their amplitude, frequency, phase, or pulse width. When radio waves strike an electrical conductor, the oscillating fields induce an alternating current in the conductor. The information in the waves can be extracted and transformed back into its original form.
Famous quotes containing the word radio:
“There was a girl who was running the traffic desk, and there was a woman who was on the overnight for radio as a producer, and my desk assistant was a woman. So when the world came to an end, we took over.”
—Marya McLaughlin, U.S. television newswoman. As quoted in Women in Television News, ch. 3, by Judith S. Gelfman (1976)
“Local television shows do not, in general, supply make-up artists. The exception to this is Los Angeles, an unusually generous city in this regard, since they also provide this service for radio appearances.”
—Fran Lebowitz (b. 1950)
“England has the most sordid literary scene Ive ever seen. They all meet in the same pub. This guys writing a foreword for this person. They all have to give radio programs, they have to do all this just in order to scrape by. Theyre all scratching each others backs.”
—William Burroughs (b. 1914)