Navigators know that the shape of surface waves provides information about the strength of underlying water currents. This common seafarer’s knowledge is now the object of the scientific inquiry.

So far we have only considered the amplitude of single sources of sound. However, in most practical situations more than one source of sound is present; these may result from other musical instruments ...

Varying the voltage of a carrier or a direct current in order to transmit analog or digital data. Amplitude modulation (AM) is the oldest method of transmitting human voice electronically. In an ...