用于中红外痕量气体检测的光电信号高速采集系统设计  

High-speed Optical Signal Acquisition System for Trace Gases Detection in Mid-infrared Absorption Spectrum

作　　者：吕默[1] 陈晨[2] 王一丁[1] 

机构地区：[1]吉林大学集成光电子学国家重点联合实验室,电子科学与工程学院,长春130012 [2]吉林大学地球信息探测仪器教育部重点实验室,仪器科学与电气工程学院,长春130061

出　　处：《激光杂志》2016年第2期26-29,共4页Laser Journal

基　　金：中国国家科技支撑计划“煤矿突水、火灾等重大事故防治关键技术与装备研发”重大课题,煤矿用红外CO检测仪(传感器)研发(2013BAK06B04)

摘　　要：在中红外波段,大多数气体分子吸收光谱的线宽都很窄,因此红外光电探测器输出信号为窄脉冲信号。对此脉冲信号的处理要求前置放大器必须兼具精度与速度,而对放大器输出信号的采集也需要在保证带宽的情况下尽量提高数字化的精度。本文中设计了高速并行采样电路,利用两片双通道高速ADC实现了1GSPS的采样速度与12bit的垂直分辨率。信号链的最后一环是FPGA数据处理电路,我们应用CORDIC算法对采集系统的时间误差进行了校正。本文最后给出了光电信号高速采集电路的设计与测试结果,在输入参考信号频率为100MHz时,采集系统整体信噪比达到60d B,无杂散动态范围达到70d B。At mid-infrared band,the spectral linewidth of most gas molecular absorption is very narrow. Besides,considering the pulse driving method of the detector,the output signal of the infrared photodiode must be narrow pulsed signal.Thus,the prepositive amplifiers must have high speed and high resolution features with very low input impedance and high working bandwidth.In this paper,a high speed,time-interleaved parallel data acquisition system is designed by using two-channel high speed ADC and the sampling speed and vertical resolution is 1Gbps and 12 bit respectively.The final step of the signal chain is the FPGA based signal processing circuit,we use CORDIC algorithm to correct acquisition system time errors.Finally,we give the design and test results of this circuit.In the case of 100 MHz input reference signal,the overall acquisition system SNR ratio reach to 60 d B,spurious-free dynamic range is up to 70 d B.

关 键 词：痕量气体检测 时间交替并行采样系统 Farrow滤波器 CORDIC算法 

分 类 号：TN91[电子电信—通信与信息系统]