Waves Modulation

Modulation means to vary or change. In wireless we first take a signal, say a telephone spoken "love" word, and then impress it on a constant sea wave called a carrier. Once done the voice signal varies or modulates this sea wave. The two go together over the water. A voice frequency in the audible or audio range, what we can hear, thus modulates or varies a constant frequency in the sea waves range, which we can't hear. That's an important point. Modulation makes voice band and sea band frequencies work together. Different modulation techniques, such as A.M., F.M., P.C.M. and so on, represent different ways to shape or form sea waves.