Data acquisition system design of high-precision linear-polarimeter

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 signaltonoise 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.