Radio
![The Alexandra Palace, here: mast of the broadcasting station](/Images/godic/202502/05/Alexandra_Palace_mast1702.JPG")
![Classic radio receiver dial](/Images/godic/202502/05/The_PVR1702.jpg")
![Radio communication. Information such as sound is converted by a transducer such as a microphone to an electrical signal, which modulates a radio wave sent from a transmitter. A receiver intercepts the radio wave and extracts the information-bearing electronic signal, which is converted back using another transducer such as a speaker.](/Images/godic/202502/05/Signal_processing_system1702.png")
![An audio signal (top) may be carried by an AM or FM radio wave.](/Images/godic/202502/05/Amfm3-en-de1703.gif")
Radio is the use of radio waves to carry information, such as sound, by systematically modulating some property of electromagnetic energy waves transmitted through space, such as their amplitude, frequency, phase, or pulse width. When radio waves strike an electrical conductor, the oscillating fields induce an alternating current in the conductor. The information in the waves can be extracted and transformed back into its original form.