Noise

Noise:

External Noise in Communication System : The various forms of External Noise in Communication System created outside the receiver are namely 1. Atmospheric Noise, 2. Extraterrestrial Noise, Solar noise Cosmic noise 3. Industrial Noise.   1.Atmospheric Noise: Perhaps the best way to become acquainted with atmospheric noise is to listen to shortwaves on a receiver which is not well equipped to receive them. An astonishing variety of strange sounds will be heard, all tending to interfere with the program. Most of these sounds are the result of spurious radio waves …


Internal Noise in Communication System : Under the heading of Internal Noise in Communication System, we discuss noise created by any of the active or passive devices found in receivers. Such noise is generally random, impossible to treat on an individual voltage basis, but easy to observe and describe statistically. Because the noise is randomly distributed over the entire radio spectrum there is, on the aver­age, as much of it at one frequency as at any other. “Random noise power is propor­tional to …


Noise Calculation in Electronic Communication System : The Noise Calculation in Electronic Communication System are namely, 1.Addition of Noise due to Several Sources: Let’s assume there are two sources of thermal agitation noise generators in series: Vn1 = √4kT δf R1 and Vn2 = √4kT δf R2. The sum of two such rms voltages in series is given by the square root of the sum of their squares, so that we have It is seen from the previous equations that in order to find the total noise voltage …


Noise Figure in Communication System : The Noise Figure in Communication System are namely, 1.Signal to Noise Ratio: The calculation of the equivalent noise resistance of an amplifier, receiver or device may have one of two purposes or sometimes both. The first purpose is comparison of two kinds of equipment in evaluating their performance. The second is comparison of noise and signal at the same point to ensure that the noise is not excessive. In the second instance, and also when equivalent noise resistance is …


Noise Temperature in Communication System : The concept of noise figure, although frequently used, is not always the most convenient measure of noise, particularly in dealing with UHF and microwave low-noise antennas, receivers or devices. Controversy exists regarding which is the better all-around measurement, but noise Noise Temperature in Communication System, derived from early work in radio astronomy, is employed extensively for antennas and low-noise microwave amplifiers. Not the least reason for its use is convenience, in that it is an additive …