Noise-equivalent power expresses detector noise as an equivalent incident radiant power. In a bandwidth-normalized convention, divide the output amplitude amplitude spectral density by spectral responsivity; the units are . It is the incident signal scale giving unit signal-to-noise ratio in a noise-equivalent detection bandwidth.[ref]
NEP – Noise Equivalent Power by Thorlabs. Definition, bandwidth normalization and conversion to integrated noise
For approximately white noise, a bandwidth gives equivalent rms radiant power . Thus over corresponds to . State the wavelength, operating conditions and bandwidth: a bandwidth-normalized specification is not itself a universal minimum detectable energy.
Noise-equivalent radiance is the incident radiance change producing signal-to-noise ratio one for a specified spectral and electrical bandwidth. A linear radiometer with voltage response and RMS voltage noise has . Its convention must distinguish per-sample noise from a noise amplitude per square-root bandwidth.
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Noise-equivalent power (NEP) is a key parameter used to describe the sensitivity of a detector or sensor, often in the context of optical and infrared detectors. It quantifies the minimum power of an incoming signal that can be reliably detected above the noise level of the system. Specifically, NEP is defined as the incident power of a signal that produces a signal-to-noise ratio (SNR) of one when integrated over a given bandwidth.