Communicating With Waves - Terminology
People can communicate with each other using electromagnetic (typically radio) waves, sound waves or ultrasound but these systems have features in common. These include
A transducer which changes a signal from one form to another eg sound to electrical energy.
An encoder which translates the signal into a form which can be easily transmitted. This might be changing an electrical signal into an digital form easily transmitted as 0's and 1'
a modulator produces periodic variations in amplitude and/or frequency of the wave that carries the signal
An amplifier increases the amplitude of the signal
A transmitter sends the signal from one place to another
A receiver detects the transmitted signal
A demodulator seaparates a coded signal from the wave that carries it
A decoder translates the information from the form in which it is transmitted to one in which it can be understood