Question

Why amplitude modulation is more more sensitive to noise then in frequency modulation

Answer 1

There are many good answers here, but taking things down to the basics:

In AM, the information is carried in the AMPLITUDE (Strength) of the signal. So any time there is a static pulse it will be heard as a “Pop”. A lightning storm will come through as a string of static. Every time a motor starts or stops, there will be static. That’s just the nature of the beast.

FM is carried as the FREQUENCY of the signal, and the signal is highly amplified then “clipped” so that amplitude changes are filtered out before the signal is detected, thus all those Snap-Crackle-Pops are GONE, and nothing is heard but the original modulation!

Note that with the old analog television transmissions, the picture was carried as an AM signal but the sound was carried as an FM signal, so when there was electrical noise, you would see a lot of black “dots” in the picture, and since most TVs did not use good “clipping” in the audio, you may also hear interference. Hopefully the newer digital TV has cured this problem.