A radio is an electronic device that receives electromagnetic waves transmitted over the air and converts them into sound. These waves, called radio waves, are a type of electromagnetic radiation. A radio station transmits sound (usually music, voice, or signals) by encoding it into radio waves using modulation techniques like AM or FM. The radio’s antenna receives these waves, and internal components like the tuner, demodulator, and amplifier work together to extract and play back the sound through the speaker.
While several inventors contributed to the development of radio technology, Guglielmo Marconi is most often credited with inventing the first successful wireless telegraphy system around 1895. He demonstrated the ability to send Morse code signals over long distances without wires, and in 1901, he made the first successful transatlantic radio communication. Others, such as Nikola Tesla, Heinrich Hertz, and Reginald Fessenden, also played vital roles in radio’s development.
There are several types of modulation, but the two main ones for audio broadcasting are:
Amplitude Modulation (AM): Varies the strength (amplitude) of the signal while the frequency remains constant.
Frequency Modulation (FM): Varies the frequency of the wave while the amplitude stays the same.
Others include Single Side Band (SSB), Phase Modulation (PM), and Digital Modulation like QAM and PSK, used for more advanced or digital communications.
