Difference between AM Radio and FM Radio
A radio works by transmitting signals created by the modulation of electromagnetic waves at frequencies below those of visible light. Information can be carried by changing the frequency, the amplitude, the phase or the pulse width of the radiated waves.
Originally it was used for military communications. Later on, it came to be known via an increased popularity amongst broadcasting news, commercials, variety shows and music. The period between 1930 and 1955 was called the golden age of radio but after that a rivalry with television began. Obviously, aside from sound, television had the advantage of imagery and history was made. A.M. and F.M. are still the most common ways to transmit radio signals.
A.M. is the abbreviation used for amplitude modulation – a technique used in electronic communication to carry information through radio waves by varying the amplitude.
F.M. is the abbreviation used for frequency modulation – a technique used in electronic communication to carry information through radio waves by varying the frequency.
A.M. radio has a range of from 535 to 1705 kilohertz. As such, a user can find radio stations at each 10 KHz. A.M. radio can be broadcast using long, medium and short wave frequency bands. Long wave bands range from 148.5 KHz to 285.5 KHz with 9 KHz spacing between channels. These are generally used in Europe, Africa and Asia at latitudes north of 50 degrees. In the United States and Canada, long wave bands serve as aeronautical navigational aid. Medium wave bands range is from 520 KHz to 1610 KHz with 9 or 10 KHz spacing. These are used for commercial broadcasting. Short wave bands can range from 1711 KHz to 30 MHz with 5 KHz spacing. They are used for long range radio broadcasts. The quality of the sound is affected in this case.
The range for F.M. radio broadcasts is between 87.5 and 108 MHz for most countries. Exceptions from this general rule apply for Japan where the range is between 76 and 90 MHz and Eastern Europe for the countries part of the OIRT (Organisation Internationale de Radiodiffusion et de Télévision) which use the broadcast band of 65.8 MHz to 74 MHz simultaneously with the broadcast and of 87.5 and 108 MHz. F.M. stations occur each 200 KHz.
Although sound can be broadcast over longer distances via A.M. radio transmitters using frequencies up to 15 KHz, the quality is poor. F.M. radio broadcasts have better sound quality, but physical barriers can impact the signal.
Similarities and Differences
- A.M. a technique used to carry information through radio waves by varying the amplitude. F.M. a technique used to carry information through radio waves by varying the frequency.
- A.M. radio has a range from 535 to 1705 KHz with 10 KHz spacing. The range for F.M. radio broadcasts is between 87.5 and 108 MHz with 200 KHz spacing, except for Japan and Eastern Europe.
- An A.M. radio sound signal is poorer than an F.M. radio sound signal.