本文主要介绍 YB——Z——5型红外测温仪中的闭路相敏检波锁定放大器。根据相关接收技术理论,介绍该锁定放大器的设计思想、具体电路、性能指标。该机具有能在强噪声下检测微弱信号不失真,恶劣环境下连续工作稳定性强的特点。适当改变参数后,可实现不同频率的锁定,适用于其它仪表微弱信号的检测。 This article mainly introduces the phase sensitive detection locked amplifier in YB - Z - 5 infrared thermometer. According to the relevant receiving technology theory, introduces the design idea of ​​the lock-in amplifier, the specific circuit, performance indicators. The machine has the ability to detect weak signals under strong noise without distortion, continuous working stability under harsh environments. Appropriate changes to the parameters, the lock can be achieved at different frequencies, for weak signal detection of other instruments.