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In the simple version above, the signal and noise are fully uncorrelated, in which case + is the total power of the received signal and noise together. A generalization of the above equation for the case where the additive noise is not white (or that the / is not constant with frequency over the bandwidth) is obtained by treating the channel as many narrow, independent Gaussian ...
Telecommunication systems strive to increase the ratio of signal level to noise level in order to effectively transfer data. Noise in telecommunication systems is a product of both internal and external sources to the system. Noise is a random process, characterized by stochastic properties such as its variance, distribution, and spectral density.
An optical communication system is any form of communications system that uses light as the transmission medium. Equipment consists of a transmitter, which encodes a message into an optical signal, a communication channel, which carries the signal to its destination, and a receiver, which reproduces the message from the received optical signal.
One of the causes of intersymbol interference is multipath propagation in which a wireless signal from a transmitter reaches the receiver via multiple paths. The causes of this include reflection (for instance, the signal may bounce off buildings), refraction (such as through the foliage of a tree) and atmospheric effects such as atmospheric ducting and ionospheric reflection.
/ must be used with care on interference-limited channels since additive white noise (with constant noise density ) is assumed, and interference is not always noise-like. In spread spectrum systems (e.g., CDMA), the interference is sufficiently noise-like that it can be represented as and added to the thermal noise to produce the overall ratio
Noise reduction, the recovery of the original signal from the noise-corrupted one, is a very common goal in the design of signal processing systems, especially filters. The mathematical limits for noise removal are set by information theory .
A signal strength and readability report is a standardized format for reporting the strength of the radio signal and the readability (quality) of the radiotelephone (voice) or radiotelegraph (Morse code) signal transmitted by another station as received at the reporting station's location and by their radio station equipment.
In wireless communications, channel state information (CSI) is the known channel properties of a communication link.This information describes how a signal propagates from the transmitter to the receiver and represents the combined effect of, for example, scattering, fading, and power decay with distance.