基于某制冷型红外焦平面探测器, 介绍了一种高信噪比的模拟信号采集电路。使用了噪声分析法对电路噪声来源进行分析, 建立了低噪声的信号变换路径; 采用信噪比(SNR)和噪声等效温差(NETD)测试相结合的方法, 对电路和成像组件指标进行评价; 测试结果表明, 组件SNR可达76 dB, NETD可达17. 5 mK(环境温度300 K), 信号采集过程中噪声引入量少, 组件能够实现对远距离微弱小目标的探测。

An analogue-signal acquisition circuit with high Signal-to-Noise Ratio (SNR) is introduced based on a cooled infrared focal-plane detector. The source of the circuit noise is analyzed by using the noise analytical method, and the signal transformation path with low noise is created. Moreover, the indexes of the circuit and imaging components are analyzed by carrying out SNR test together with Noise Equivalent Temperature Difference (NETD) test. The results show that: 1) The component of SNR can reach 76 dB, and NETD can reach 17. 5 mK at environment temperature of 300 K;and 2) Less noise is introduced into the signal acquisition process, and the components can detect dim and small targets at a long distance.