摘要:
根据高精度线偏振辐射计应用需求，设计了基于电容积分法的可见光至短波红外波段偏振辐射计信号采集系统。简要介绍了高精度线偏振辐射计的工作原理，分析其采集系统具有的探测信号动态范围大、采样频率低和探测精度高的特点；建立了基于跨阻放大法和电容积分法的2种放大电路噪声模型，并推导出信噪比公式，采用DDC112的电容积分法放大电路的数据采集系统能够有效减小系统噪声、简化电路设计、提高系统灵活性和系统信噪比；实验测试了系统的动态范围、等效噪声辐亮度、信噪比、稳定性和线偏振度，并进行了外场试验。实验结果表明：该数据采集系统具有较高的响应动态范围，等效噪声辐亮度比较理想，常规气溶胶探测波段信噪比≥127，典型地表探测波段信噪比≥147，仪器稳定性优越，线偏振度测量精度优于0.5%，达到仪器设计指标。
Abstract:
According to the application requirements of high-precision linear-polarimeter, a signal acquisition system based on capacitive integration method was designed.Firstly,the working principle of the high-precision linear-olarimeter was introduced briefly, as well as its main characteristics, such as large dynamic range of the signal, low sampling frequency and high detection precision. Based on the transimpedance amplification method and the capacitor integral method, two amplification nosie models were established and its SNR formula was derivated.This signal acquisition system,rooting in a DDC112 capacitive integration detector, is capable of reducing the system noise, simplifying the circuit design and improving the system’s flexibility and signaltonoise ratio( SNR). A noise model was also established for the signal acquisition system. At last, laboratory tests were designed to test the dynamic range of the system, equivalent noise radiance, SNR, stability and linear polarization. Field experiments were also carried on. The tests and experiments show that this signal acquisition system has large dynamic range and good equivalent noise radiance. For conventional spectral band of aerosol, the SNR is above 127,for typical spectal band of earth’s surface, the SNR is above 147, the linear polarization measurement accuracy is better than 0.5 % which proves to be a good performance of the signal system.
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