Coaxial Cable

Coaxial Cable

Coaxial Cable consists of 2 conductors. The inner conductor is held inside an insulator with the other conductor woven around it providing a shield. An insulating protective coating called a jacket covers the outer conductor.
The outer shield protects the inner conductor from outside electrical signals. The distance between the outer conductor (shield) and inner conductor plus the type of material used for insulating the inner conductor determine the cable properties or impedance.
• It has better shielding than twisted pairs, so it can span longer distances at higher speeds.
• Two kinds of coaxial cable are widely used. One kind is 50-ohm cable which is commonly used when it is intended for digital transmission from the start.
• The other kind is 75-ohm cable which is commonly used for analog transmission and cable television but is becoming more important with the advent of Internet over cable.
• A coaxial cable consists of a stiff copper wire as the core surrounded by an insulating material.
• The insulator is encased by a cylindrical conductor, often as a closely-woven braided mesh.
• The outer conductor is covered in a protective plastic sheath.
• The construction and shielding of the coaxial cable give it a good combination of high bandwidth and excellent noise immunity.
• The bandwidth possible depends on the cable quality, length and signal-to-noise ratio of the data signal. Modern cables have a bandwidth of close to 1 GHz.
• Coaxial cables used is widely used within the telephone system for long-distance lines but have now largely been replaced by fiber optics on long-haul routes.

Twisted Pair Cable