Transmission impairments are described below:
In the data communication system, analog and digital signals go through the transmission medium. Transmission media are not ideal. There are some imperfections in transmission mediums. So, the signals sent through the transmission medium are also not perfect. This imperfection cause signal impairment.
It means that signals that are transmitted at the beginning of the medium are not the same as the signals that are received at the end of the medium that is what is sent is not what is received. These impairments tend to deteriorate the quality of analog and digital signals.
fig:- Impairment causes
It means a loss of energy. The strength of signal decreases with the increasing distance which causes loss of energy in overcoming the resistance of the medium. This is also known as the attenuated signal. Amplifiers are used to amplify the attenuated signal which gives the original signal back.
• Distortion – It means a change in the shape of the signal. This is generally seen in composite signals with different frequencies. Each frequency component has its own propagation speed traveling through a medium. Every component arrives at a different time which leads to delay distortion. Therefore, they have different phases at the receiver end from what they had at the sender’s end.
• Noise – The random or unwanted signal that mixes up with the original signal is called noise. There are several types of noise such as induced noise, crosstalk noise, thermal noise and impulse noise which may corrupt the signal.
Induced noise comes from sources such as motors and appliances. These devices act as sending antenna and transmission medium act as receiving antenna. Thermal noise is the movement of electrons in the wire which creates an extra signal. Crosstalk noise is when one wire affects the other wire. Impulse noise is a signal with high energy that comes from lightning or power lines
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