it is trade off b/w bandwidth and less noise,anyways in frequency modulation information is in frequency,where most of noises disturb the amplitude so ur information is not effected
hi
Frequency modulation has better performance because it is more robust again noise. in fact in frequency modulation data are transmitted by frequency while in amplitude modulation data are conveyed by amplitude so the additive thermal noise which adds to the amplitude of signal has worse effect on AM while the effect of thermal noise on FM can be ignored.