Am
Variation of the amplitude of a carrier wave (commonly a radio wave) in correspondence to fluctuations in the audio or video signal being transmitted. AM is the oldest method of broadcasting radio programs. Commercial AM stations operate in the frequency range of 535 to 1605 kHz. Because radio waves of these frequencies are reflected back to the Earth's surface by the ionosphere, they can be detected by receivers hundreds of miles away. In addition to commercial radio broadcasting, AM is also employed in short-wave radio broadcasts, and in transmitting the video portion of television programs. FM.
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a.m.
[Etymology: ante meridian, i.e. before the meridian] time Indicative of a time before noon, i.e. before the Sun nominally reaches the meridian, so the time is before the meridian. See p.m. for discussion.
abbr. amplitude modulation.
See the Introduction, Abbreviations and Pronunciation for further details.
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- Radios and Radio Technology - AM: amplitude modulation broadcasting band
- Abbreviations - AM: amplitude modulation
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Mentioned in
Croft, Roy
(Quotes By)
Sanders, George
(Quotes By)
Smith, Minnie
(Quotes By)
Am.
(abbreviation)
Al-Sabah, Nawaf Al-Nasir
(Quotes By)
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