Weak signal conditioning circuit design has a direct impact on detecting accuracy of passive FTIR spectroscopy. Designing the pre-amplifier circuit and the secondary amplifier circuit based on HgCdTe infrared Detectors which transfers the interference light to 10-8mA weak current of the output electrical signal. The circuit has high gain, high SNR, phase compensation, noise and temperature drift reduced, and large dynamic input range. Under the conditions of weak input current signal, measurement testing results of conditioning circuit show that the circuit has high accuracy, good stability, simple structure, and easy to implement It can be verified to its correctness and feasibility in the application of spectrometer.%微弱信号调理电路设计的好坏直接影响到被动傅里叶变换红外光谱仪(FTIR)的探测精度.基于HgCdTe光电导型红外探测器接受干涉光后输出的微弱电信号来设计前置检测电路和放大电路,该电路具有高增益、高信噪比、相位补偿功能,有效降低了噪声和温漂以及大的动态输入范围等特性.红外探测器将干涉红外光转换为10-8mA数量级的微弱电信号,在此输入条件下对信号调理电路进行实测,试验结果表明,该电路测量精度高,具有较好的稳定性,且结构简单易实现,可以在光谱仪应用中验证其正确性和可行性.
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