Subject: Priniciples of Communication Engineering

Difficulty : Medium

Marks : 05

FM is frequency modulatoon. It is defined as the process in which frequency of the carrier is varied in accordance with instantaneous amplitude of the modulating signal. FM signal is having fixed amplitude and phase and frequency is variable.

Noise is generally uniformly spread across the spectrum and varies randomly in amplitude. The change in amplitude can modulate the signal and can be picked up in an AM system. FM systems are inherently immune to random noise. For noise to interfere in FM, it will have to modulate the freq somehow but noise is distributed uniformly, in freq and varies mostly in amplitude. So FM is more immune to noise.