当信噪比小于1时,锁定放大器仍能从噪声中得到信号。在光度计和辐射计系统中一种有用的方法是相敏或同步检波。以此技术为基础的实用仪器是锁定放大器。在最大信号功率小于总噪声功率的弱信号测量中,能用来测量的方法是降低噪声功率。在光度计系统中,噪声源总是与探测器、测量系统环境和电子系统的输入级有关。对 When the signal to noise ratio is less than 1, the lock-in amplifier can still get the signal from the noise. A useful method in photometer and radiometer systems is phase-sensitive or synchronous detection. A practical instrument based on this technology is a lock-in amplifier. In weak signal measurements where the maximum signal power is less than the total noise power, the method that can be used to measure is to reduce the noise power. In photometric systems, the source of noise is always related to the detector, the measurement system environment, and the input stage of the electronic system. Correct