Transmission Impairement

When the received signal is not identical with that of transmitted signal, then the quality of signal is degraded. This is called transmission impairement.

Causes of Transmission Impairement

1. Attenuation
   Attenuation means loss of energy i.e. the strength of signal decreases with increasing the distance which causes loss of energy.

2. Distortion
   Distortion occurs when there is change in shape of the signal. Each frequency componenet has its own propagation speed, so they reach at a different time which leads to distortion.

3. Noise
   When the data is transmitted over a medium, some unwanted siganl is added to it which causes the noise.