FM
Understanding FM
FM provides superior noise immunity compared to AM because amplitude noise does not affect the frequency of the received signal. The deviation ratio and modulation index determine the bandwidth and signal-to-noise performance of an FM system.
Carson's rule approximates FM bandwidth as 2(delta_f + f_m), where delta_f is the peak frequency deviation and f_m is the highest modulating frequency. Wideband FM (WBFM) provides better SNR but requires more spectrum than narrowband FM (NBFM).
Frequently Asked Questions
What is the advantage of FM over AM?
FM is inherently resistant to amplitude noise and interference, providing cleaner audio and better performance in multipath environments.
What is frequency deviation?
Deviation is the maximum change in carrier frequency from its center value, proportional to the amplitude of the modulating signal.