1) I understood how variations in the amplitude of modulating signals are represented in the carrier wave, but I didn't get how frequency variations of the modulating signal are represented, as both AM and FM modulations seem do not care about it. Ex: How to distinguish a high vocal range (high frequency) from a low vocal range (low frequency). 2) I didn't get the concept of bandwidth. Is the modulation bandwidth the same of computing bandwidth? And how the frequency of a carrier wave interfere the amount of information you can send for period of time? Why the higher frequency of a FM signal helps on increasing the quality of it in comparison with AM.