How does noise affect signals? what happens if the level of noise becomes too high relative to the strength of the signal.

Noise could be defined as electromagnetic fields that affect analog signals that are constantly changing. This process does not occur in a similar way with digital signals, which have fixed electrostatic pulses (For this reason they are able to withstand 'noise' because the power of these signals are much stronger than the power coming from noise).

That phenomenon does not happen with the analog signals which have a variable intensity and become vulnerable to any electronic noise interference.

When very high electromagnetic fields are generated, the waves of the analog signal cannot be perceived which causes problems in the transmitted signal (making it unintelligible to the receiver)