fm vs am

923 Words2 Pages

AM VS FM
Have you ever wondered why the fm radio in your car has a higher sound quality when compared to the am radio?
But why the am radio has a longer range than the fm radio wave?
The following extract will cover the wave theory, wave carriers, and modulation in order to give a thorough understanding of am and fm waves and their surrounding concepts.

THE WAVE THEORY:
The wave theory states that- waves transfer energy from one point to another; however they do so without transferring matter. They consist of disturbances within the wave, which is what creates the two varying wave types- longitudinal and transverse.
A transverse wave is a wave in which the vibrations or particles of the medium travel perpendicular to the direction in which the wave is travelling.
For example: if a buoy was placed out in the middle of the ocean were multiple sets of waves occur, the buoy would only move up and down, however the sets of waves continue to move forward towards the shore; the same principle applies to sound waves, indicating the particles of the medium travel perpendicular to the direction of the wave.
Refer to figure 2 for a visual understanding.

The height of the crest from the equilibrium is known as the amplitude.
A longitudinal wave on the other hand is where the particles of the medium move in the same direction as the wave. Energy is passed along the air molecules through the lengthway vibrations of a longitudinal wave. This process continues throughout the entire wave, and t...

... middle of paper ...

....
In order to calculate the bandwith that an FM wave produces, the sum of the modulating frequency is doubled, as well as the frequency deviation.
For example, if the frequency deviation is 75kHz, and the modulating signal frequency is 15 kHz, the bandwith required to transmit the signal has to be 180kHz.
The frequency deviation refers to the maximum instantaneous difference between an FM modulated frequency and the carrier frequency.
As was stated in “AM vs FM” each type of modulation has its own pros and cons. Although AM has the ability to have more channels available within a given range, the overall sound quality is not particularly good, due to the fact that sound is stored in the amplitude part of the wave; and ofcourse this is what is being modulated. Therefore, FM radio broadcasts are overall better due to the higher quality of sound which it produces.

More about fm vs am

Open Document