Transmitters are devices that are used to send out data as radio waves in a specific band of the electromagnetic spectrum in order to fulfill a specific communication need, be it for voice or for general data. In order to do this, a transmitter takes energy from a power source and transforms this into a radio frequency alternating current that changes direction millions to billions of times per second depending on the band that the transmitter needs to send in. When this rapidly changing energy is directed through a conductor, in this case an antenna, electromagnetic or radio waves are radiated outwards to be received by another antenna that is connected to a receiver that reverses the process to come up with the actual message or data.

A transmitter is composed of:

• Power supply — The energy source used to power the device and create the energy for broadcasting


• Electronic oscillator — Generates a wave called the carrier wave where data is imposed and carried through the air


• Modulator — Ads the actual data into the carrier wave by varying some aspect of the carrier wave


• RF amplifier — Increases the power of the signal in order to increase the range where the waves can reach


• Antenna tuner or impedance matching circuit — Matches the impedance of the transmitter to that of the antenna in order for the transfer of power to the antenna to be efficient and prevent a condition called standing waves, where power is reflected from the antenna back to the transmitter, wasting power or damaging it