What does the term “attenuation” mean in data communication? A. loss of signal strength as distance increases B. strengthening of a signal by a networking device C. leakage of signals from one cable pair to another D. time for a signal to reach its destination
The Correct Answer and Explanation is:
A. loss of signal strength as distance increases
Explanation
In the field of data communication and telecommunications, attenuation refers to the gradual reduction in the strength or intensity of a signal as it travels through a transmission medium. This loss of energy is a natural and unavoidable phenomenon that affects all types of signals, whether they are electrical signals in a copper wire, light pulses in a fiber-optic cable, or radio waves traveling through the air.
The primary cause of attenuation is the transmission medium itself, which presents opposition to the signal’s propagation. In copper cabling, this opposition comes from electrical resistance, which converts some of the signal’s energy into heat. For wireless communications, signals attenuate as their energy disperses over a progressively larger area, a principle often described by the inverse-square law. In fiber-optic cables, attenuation is caused by the absorption and scattering of light as it travels through the glass or plastic core.
The consequence of attenuation is a decrease in the signal-to-noise ratio (SNR). As a signal becomes weaker, it becomes more difficult for the receiving device to distinguish it from the inherent background noise present in any communication system. If the signal attenuates too much, the receiver may be unable to accurately interpret the data, leading to bit errors and a corrupted transmission.
To combat the effects of attenuation, network designs incorporate specific strategies. First, communication standards, such as Ethernet, impose strict distance limitations on cable lengths (e.g., 100 meters for UTP cables) to ensure the signal remains intelligible at its destination. Second, for transmissions over longer distances, devices like repeaters (for digital signals) or amplifiers (for analog signals) are used. A repeater receives a weakened signal, regenerates it to its original strength and form, and retransmits it, effectively resetting the distance clock on attenuation.thumb_upthumb_down
