Electro-optic modulator

In telecommunication, an equivalent noise resistance is a quantitative representation in resistance units of the spectral density of a noise-voltage generator, given by $R_{n}={\frac {\pi W_{n}}{kT_{0}}}$ where $W_{n}$ is the spectral density, $k$ is the Boltzmann's constant, $T_{0}$ is the standard noise temperature (290 K), so $kT_{0}=4.00\times 10^{-21}\,[Ws]$.

Note: The equivalent noise resistance in terms of the mean-square noise-generator voltage, e², within a frequency increment, Δ f, is given by

$R_{n}={\frac {e^{2}}{4kT_{0}\,\Delta f}}.$

See also

• Equivalent input noise
• Effective input noise temperature