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FM
FM គឺជាពាក្យកាត់នៃពាក្យ Frequency Modulation។
[[File:Amfm2.gif|thumb|right|A sound wave, an '''AM''' wave, and an '''FM''' wave compared]]

In [[telecommunication]]s and [[signal processing]], '''Frequency modulation''' transmits [[information]] over a [[carrier wave]] byvarying the [[frequenxy]].  This technique is different from [[amplitude modulation]] which varies the [[amplitude]], but keeps the frequency constant. In the context of [[broadcasting]] [[radio]] [[signal]]s, Frequency modulation is often shortened to '''FM'''. When transmitting [[analogue]] [[sound]],  the sound quality of FM signals is better than that of [[amplitude modulation]] (AM) signals. However, FM signals do not travel as far as AM.

Many radio stations send out both kinds of signals, reserving AM for talk shows, and FM for music. In addition, FM is usually sent as two signals (with one signal's frequency a little lower than the other), which can come to two different speakers in a home. This creates FM [[stereo]] sound.

== Other websites ==
* [http://www.rfcafe.com/references/electrical/frequency_modulation.htm Frequency Modulation] 
* [http://www.fas.org/man/dod-101/navy/docs/es310/FM.htm Frequency Modulation]
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[[Category:Radio]]{{delete|មិនមែនភាសាខ្មែរ}}