Difference Between AM and FM

AM vs FM

AM and FM, we often come across these terms when listening to radio but wonder what they are and how to differentiate between the two. Well, for starters, AM and FM are means of sending information through airwaves which people listen over their radios. There are basic differences between the two apart from the fact that transmission using FM is much clearer than that of AM.

AM stands for amplitude modulation, while FM means frequency modulation. Now what is this modulation? Modulation refers to the act of modifying some aspect of the frequency to make it suitable as per the information being carried. It is clear then that in AM, it is the amplitude that is modified while in FM it is the frequency that undergoes modification.

In radio broadcasting, AM came before FM, and this explains some of the drawbacks that are associated with AM. AM is more suitable for short distances, and is susceptible to weather changes. FM is immune to weather, can carry signals to great length and is clearer of the two and almost perfect for music and other vocals.

AM is technologically simpler of the two and this is why it soon became very popular with the people. Millions of radio sets were sold as people were fascinated to receive voice on their receivers. But AM was susceptible to weather and it led to deterioration in sound quality when the weather was bad. The signals got distorted making it a bad experience for the listener. Then there was the limitation of a single audio channel which meant that AM could not be used for stereo broadcasting. This gradually led to an enchantment among the people and radio was slowly becoming a thing of the past when FM came along and popularized radio once again.

FM has many advantages over AM though it is a more complex technology. Using advanced algorithms, it is possible to send information through two channels which allows for left and right audio channels, making it a stereo sound for the listener. Changes in weather have no effect on FM broadcast as such changes affect only amplitude and not frequency which is what is controlled in FM technology.

However, when it comes to broadcasting over longer distances, AM is better as it can carry signals to far off places, even thousands of kilometers away, whereas FM is clearer over shorter distance range. This is why you have local FM stations in every city.


Both AM and FM are used for sending information through airwaves.

AM is simpler of the two and easily set up, but FM is clearer of the two.

‘AM’ can carry information to longer distance which FM cannot which explains local FM stations.

AM broadcast is in Mono but FM can be broadcast in stereo.