锁定放大器是利用相关技术从噪声中提取微弱信号的常用方法之一。可以证明，当信号的频率和相位已知时，使用相关检测技术能使输出信号信噪比最大。数字锁定放大器比模拟锁定放大器具有稳定、精度高等优点，并且数字滤波器的通带可以设置的非常窄，以便滤除噪声。-Lock-in amplifier is a common method using correlation techniques extracting weak signals　the noise in. It can be shown when the frequency and phase of the signal is known, the use of correlation detection technology enables maximum output signal to noise ratio. Digital lock-in amplifier than analog lock-in amplifier with a stable, high precision, and a digital filter passband can be set very narrow, in order to filter out noise.