Doppler spread

Imagine you are standing outside and a car drives past you. The sound of the car's engine changes as it drives towards you and then away from you. This happens because of something called the Doppler effect. When something is moving towards you, the sound waves get compressed and sound higher. When it moves away, the sound waves get stretched and sound lower.

Now imagine this happening with radio signals instead of sound waves. When a radio signal travels through the air, it also experiences the Doppler effect. This causes the frequency of the signal to change a little bit. This change in frequency is called the Doppler spread.

So, if you have a signal that is being sent from one place to another, and the place it is coming from is moving, the frequency of the signal will change a little. This is because of the Doppler effect. The amount of change is called the Doppler spread.

Doppler spread is important because it can cause interference with other signals that are nearby. It can also make it harder to decode the signal correctly because the frequency is not exactly what was expected. Scientists and engineers have to take Doppler spread into account when designing communication systems or studying the behavior of objects that are moving.