Production of sound messages by a microphone in a radio station (studio).

1) Audio frequency generation.
2) Generation of r.f. carrier wave.
3) Modulation in a transmitter,
b) 4) Transmitting antenna on a tower,
c) Radio receiver,
5) Receiving antenna,
6) Tuning circuits,
7) Detector (demodulator),
8) Amplifier,
9) Speaker.

Production of sound and modulated waves : In the studio, the music or song is converted into electrical signals using a microphone. These signals are in the audio frequency (a.f) range. An osillator produced suitable r.f. carrier wave.

Radio transmitter or modulator: The a.f. signal and r.f. waves are combined in the transmitter. The modulated (combined) waves are fed for an antenna fixed on a tower. This transmitting antenna broadcasts the modulated r.f. waves into space. 

Radio Receiver: The aerial of a radio receiver receives the modulated waves transmitted by various radio stations. The tuning circuit inside the radio set selects only the desired signal. The detector circuits demodulates the modulated signals. Then the a.f. signal is fed to an amplifier. The amplified electric signals are fed to a speaker and converted into the music or song.