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posted by:
radiorevolt
2004-07-30 14:16:38
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What is the difference between FM and AM?
Amplitude modulation v. Frequency modulation. Essentially, FM radio and AM radio work in the same way. The difference is in how the carrier wave is modulated, or altered. The overall strength (of amplitude) of AM means that the signal is varied to incorporate the sound information, while with FM, the frequency (the number of times each second that the current changes direction) of the carrier signal is varied.
Both AM and FM signals are susceptible to slight changes in amplitude. With an AM broadcast, the changes produce static, but an FM broadcast is not really affected by changes in amplitude as audio signal is conveyed through frequency changes. Thus FM signals have a great advantage in terms of sound clarity.
AM frequency bandwidth is 550 kHz (kilo hertz) to 1600 kHz, and FM bandwidth, 88 MHz (mega hertz) to 108 MHz.
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posted by:
ERobertG
2004-12-07 20:52:13
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Actually AM radio band now extends up to 1700 kHz. Since 1994 radios have been produced with this added coverage and a few stations have been added here. This is an area where would be pirates should populate before Clear Channel and Disney take over. Check the FCC page under Audio AM.
The FM band is too crowded these days.
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