Indicate which one of the following is not an advantage of FM over AM :
UGC NET - 2012,
Answer: B
The statement that is not an advantage of FM over AM is that a lower bandwidth is required, option (B). Frequency modulation spreads the signal over a much wider band than amplitude modulation, which is why commercial FM uses a channel width of 200 kHz, against 10 kHz for AM. Better noise immunity, option (A), is the chief advantage of FM, since noise adds mainly to amplitude, which an FM receiver removes with a limiter. In FM the transmitted power is more useful, option (C), because all the power goes into the information-carrying sidebands and carrier at constant amplitude. Less modulating power, option (D), is required, since the modulator works at a low level.
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