红外微弱信号的放大与调理电路设计

Design of an Amplifying and Conditioning Circuit for Weak Infrared Signal

从热电堆红外探测器的检测电路设计入手,讨论了微弱信号的放大和调理方法,分析了热电堆探测器输出信号的时频域特性和噪声,给出了各环节的实现电路并进行了仿真,分析了以前置放大器为主的模拟信号链的噪声,并提出了噪声匹配的新方法,最终实现了微弱信号的测量。测试结果表明,本电路在噪声抑制和失调补偿方面达到了理想的效果,最小可检测到3.5μV的微弱直流信号变化,在红外光谱探测以及微弱直流信号检测中可以有较广泛的应用。

A detecting circuit of an infrared thermopile is introduced. Then the output signal and noise of the detector are analyzed. With calculating the inherent noise of the analog signal chain, the amplifying and conditioning method of weak signal are studied and a new method of noise match is proposed. The circuit design of each step is also given out, which has been simulated with Pspice. The test result shows that the design has achieved a good result in noise suppression and offset compensation, which can detect minimal 3.5 μV weak DC signal. This design can be widely used in infrared spectrum detection and weak DC signal detection of μV class