Noise-equivalent temperature

Noise-equivalent temperature (NET) is a measure of the sensitivity of a detector of thermal radiation in the infrared, terahertz or microwave portions of the electromagnetic spectrum. It is the amount of incident signal temperature that would be needed to match the internal noise of the detector such that the signal-to-noise ratio is equal to one. Often the spectrum of the NET is reported as a temperature per root bandwidth. A detector that measures power is often interested in the analogous noise-equivalent power (NEP). If a relation between intensity and temperature is well defined over the pass band, as in the case of a blackbody, then the NET simply scales with the NEP.