摘要
为了实现甲烷气体检测系统的小型化和数字化,设计了一种基于STM32的正交锁相放大器。通过STM32F407内部的A/D转换器采集反射光信号,与相位差为90°的两个参考信号分别进行乘法运算和FIR低通滤波,对两路信号求平方和并进行开方运算,实现二次谐波信号的提取。STM32F407内部的运算采用内置的FPU和DSP库,大大提高运算能力和速度。通过对浓度0%~3%的甲烷气体进行标定实验,得到甲烷气体浓度与二次谐波峰值呈良好的线性关系,线性度达到99.66%,说明该设计可以满足甲烷气体检测的要求。
In order to realize the miniaturization and digitization of methane gas detection system,an orthogonal phase-locked amplifier based on STM32 was designed. The reflected light signal was collected by STM32F407 internal A/D converter,and the two reference signals with a phase difference of 90° were respectively multiplication and FIR low-pass filtering. The sum of squares and square root of the two signals were calculated to realize the extraction of the second harmonic signal. STM32F407 uses the builtin FPU and DSP library for internal operation,which greatly improves the operation capacity and speed.Through calibration experiments of methane gas with a concentration from 0% to 3%,a good linear relationship is obtained between methane gas concentration and the peak value of the second harmonic wave,with a linearity of 99.66%. The design can meet the requirements of methane gas detection.
作者
恽浩
卜雄洙
杨昊青
宋扬
YUN Hao;BU Xiongzhu;YANG Haoqing;SONG Yang(School of Mechanical Engineering,Nanjing University of Science and Technology,Nanjing 210094,China)
出处
《电子设计工程》
2023年第4期53-56,共4页
Electronic Design Engineering
