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
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