When the signal is very strong, the photon noise predominates, signal to noise ratio is not directly proportional to signal level, and care must be exercised in deriving NEP and D * from signal to noise ratio.

• 当信号很强时 ,光子噪声占主导地位 ,信噪比 (SNR)与信号水平不成正比 ,此时由信噪比导出噪声等效功率 (NEP)和D 时应格外小心。