# Noise Temperature

In electronics, noise temperature is one way of expressing the level of available noise power introduced by a component or source. The power spectral density of the noise is expressed in terms of the temperature (in kelvins) that would produce that level of Johnson–Nyquist noise, thus:

where:

• is the power (in watts)
• is the total bandwidth (Hz) over which that noise power is measured
• is the Boltzmann constant (1.381×10−23 J/K, joules per kelvin)
• is the noise temperature (K)

Thus the noise temperature is proportional to the power spectral density of the noise, . That is the power that would be absorbed from the component or source by a matched load. Noise temperature is generally a function of frequency, unlike that of an ideal resistor which is simply equal to the actual temperature of the resistor at all frequencies.

Read more about Noise Temperature:  Noise Voltage and Current, Application To Communication Systems, Noise Figure, Noise Temperature of An Amplifier Chain

### Other articles related to "noise temperature, noise temperatures, noise, temperature":

Noise Temperature of An Amplifier Chain
... The noise temperature of an amplifier is commonly measured using the Y-factor method ... If there are multiple amplifiers in cascade, the noise temperature of the cascade can be calculated using the Friis equation where = resulting noise temperature referred to the input = noise temperature of the first ... are much greater than one, then it can be seen that the noise temperatures of the earlier stages have a much greater influence on the resulting noise ...
Noise Figure - Definition
... The noise factor F of a system is defined as where SNRin and SNRout are the input and output signal-to-noise ratios, respectively ... The noise figure NF is defined as where SNRin, dB and SNRout, dB are in decibels (dB) ... The noise figure is the noise factor, given in dB These formulae are only valid when the input termination is at standard noise temperature T0, although in practice small differences in temperature do not ...
Effective Input Noise Temperature
... In telecommunications, effective input noise temperature is the source noise temperature in a two-port network or amplifier that will result in the same output noise power, when ... If F is the noise figure numeric and 290 K the standard noise temperature, then the effective noise temperature is given by T n = 290(F-1) ...
List Of Noise Topics - Engineering and Physics
1/f noise A-weighting Ambient noise level Antenna noise temperature Artificial noise Audio noise reduction Audio system measurements Bel, Bel (acoustics) Black ...

### Famous quotes containing the words temperature and/or noise:

The bourgeois treasures nothing more highly than the self.... And so at the cost of intensity he achieves his own preservation and security. His harvest is a quiet mind which he prefers to being possessed by God, as he prefers comfort to pleasure, convenience to liberty, and a pleasant temperature to that deathly inner consuming fire.
Hermann Hesse (1877–1962)

Your next-door neighbour ... is not a man; he is an environment. He is the barking of a dog; he is the noise of a pianola; he is a dispute about a party wall; he is drains that are worse than yours, or roses that are better than yours.
Gilbert Keith Chesterton (1874–1936)