FM/AM

FM or 'frequency modulation' for it's official title, aims to broadcast a high-fidelity sound for radio. FM is usually transmitted at a frequency band of around 87.0 to 108.5 MHz.

But, it does vary from country to country. FM was invented by an American engineer named Edwin Armstrong. FM can carry both a mono and stereo signal, but stereo can only be added with the aid of multiplexing and de-multiplexing.

AM stands for 'amplitude modulation', and was the primary radio broadcast used in the twentieth century. AM is less expensive to implement, due to it's technically simpler nature.

AM can be transmitted on long, medium and short wave. Short and medium AM broadcasts act differently during the day and night time, with AM signal length being optimal during the night time.

AM does suffer badly from interference, and due to it's inferior fidelity in comparison to FM and DAB, most AM broadcasts are for talk radio stations.