红外探测器的低噪声前置放大电路设计

Design of low noise preamplifier circuit for infrared detector

在红外探测器的工程应用中,前置放大电路是影响整个探测系统性能的重要组成部分。本文从制冷型碲镉汞光导红外探测器的工作特性出发,设计了一种恒流偏置的低噪声前置放大电路。对电路的工作原理以及噪声性能进行分析,并进行了电路仿真验证以及低噪声的性能测试。实验结果表明,基于窄带滤波法设计的前置放大电路信噪比达到80 dB,具有60~120 dB的可调增益,可以有效抑制噪声并检测到10-8A量级的微变交流信号,在信号检测方面达到了良好的检测效果。

The preamplifier circuit can affect the performance of the detection system in the engineering application of infrared detector.Based on the working principle of the Hg Cd Te photoconductive infrared detector,a low-noise preamplifier circuit was designed.The working principle and noise performance of the circuit were analyzed,and the circuit simulation and low-noise test were conducted.The experimental results show that the adjustable gain is 60~120 dB and the signal noise ratio of the preamplifier is 80 dB based on the narrow band filtering method,and it can effectively suppress the noise and the 10^（-8） A AC signal can be detected.The performance reaches the desired level.