Question

For guided media such as twisted pair, coaxial cable, and optical fiber, the most significant sources of signal quality impairments are Attenuation and attenuation distortion, Delay distortion, and Noise.

Describe each of the above impairments and discuss is there a solution to reduce or totally remove these impairments.

Answer 1

Attenuation:

It is the loss of strength of signal in the cable. This is measured in voltage or decibels. Because of this the signal becomes very distorted. It occurs due to extra noise such as wire leakage. The noise then interferes with the original signal and results in attenuation.

Prevention:

To avoid or minimize the attenuation in the cable the installation and link design should be given the attention. It is important to use high-quality cable with qualified connectors. It should have less insertion loss.

Attenuation distortion:

This is very much found in analog signals in the transmission of it. It occurs when the medium of transmission doesn't offer flat frequency for the given bandwidth.

Prevention:

It can be minimized by using material of lower loss that helps in minimizing the routing length of PCB. Such materials are obtained by changing the epoxy for the glass weave to get less dissipation factor.

Delay distortion:

This occurs when data signals in the network are sent via a certain speed or frequency medium. It occurs when the frequency and velocity of the signal varies. Due to which signals arrive at different times and the resultant signal is distorted.

Prevention:

There are a number of ways to prevent it from happening. One of the methods is to mitigate nonlinear impact and use input signals with no signal fluctuations. These signals have a constant envelope and it helps in reducing the delays.

Noise:

This is another form of electronic disturbance in the data. It can be due to natural sources or man-made items. The real cause of noise in a signal is sometimes the circuit, its design, and layout also. It is generated due to faulty components, switches, loose connections, etc.

Prevention:

It can be prevented by making the wire short, and keeping them far away from the machinery. Differential inputs can also be used to reduce noise.