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.
Read more about Radio: Etymology, Processes, Communication Systems, Uses of Radio
Famous quotes containing the word radio:
“We spend all day broadcasting on the radio and TV telling people back home what’s happening here. And we learn what’s happening here by spending all day monitoring the radio and TV broadcasts from back home.”
—P.J. (Patrick Jake)
“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)
“Denouement to denouement, he took a personal pride in the
certain, certain way he lived his own, private life,
but nevertheless, they shut off his gas; nevertheless,
the bank foreclosed; nevertheless, the landlord called;
nevertheless, the radio broke,
And twelve o’clock arrived just once too often,”
—Kenneth Fearing (1902–1961)