Repeaters

All transmission media attenuate (weaken) the electromagnetic waves that travel through the media. Attenuation therefore limits the distance any medium can carry data. Adding a device that amplifies the signal can allow it to travel farther, increasing the size of the network. For example, if one is connecting computers that are more than 100 meters apart using Ethernet cable, one will need a device that amplifies signals to ensure data transmission. Devices that amplify signals in this way are called repeaters.

Repeaters are fall into the following categories:

        

                a)     Amplifiers

                b)    Signal-regenerating devices (Repeaters)

Amplifiers

            Amplifiers simply increase the power of the incoming signal, i.e. both signal and the noise. These are able to improve signal to noise in the analog type systems only.

Signal regenerating repeaters

            Signal regenerating repeaters create an exact duplicate of the incoming digital data by identifying it amidst the noise, reconstructing it and passing only the desired information. In this manner, the original signal is duplicated, boosted to its original strength and then sent.

What is the use of repeaters ?

Repeaters extend the distance of a single network. So if you are using an Ethernet LAN but need to go farther than you are usually able to, you can then install a repeater to achieve the added distance. When a repeater is installed, it creates a physical break in the cable. The signal is received on one side of the repeater, regenerated and passed on to the next section of cable.