基于FPGA的高精度频率测量系统设计及应用

Design and Application of High-Precision Frequency Measurement System Based on FPGA

摘要:

针对石英晶体微天平(QCM)传感器应用于气体检测需要高精度频率测量,设计了一种基于FPGA的高精度频率测量系统。提出了一种基于锁相环的等精度频率测量方法,降低了频率测量的理论相对误差。设计了频率测量系统整体架构,根据整体架构完成了基于FPGA的高精度频率测量系统硬件电路,设计了一种包括频率测量、通讯、程序固化等模块的嵌入式软件,实现了基于FPGA的高精度频率测量系统的集成,并将其应用于基于QCM的二氧化碳气体浓度检测。实验结果表明,频率系统测量绝对误差不超过0.35Hz,误差平均值为0.268Hz,最大相对误差为3.5×10-8^,频率测量分辨率可以达到0.1Hz,该系统测量误差较小,稳定性较好,在基于QCM的二氧化碳气体浓度检测中具有较好的应用前景。

Abstract:

To meet the need for high-precision frequency measurement in gas detection using Quartz Crystal Microbalance (QCM) sensors, a high-precision frequency measurement system based on FPGA is designed. A method of equal-precision frequency measurement based on phase-locked loop is proposed, reducing the theoretical relative error of frequency measurement. The overall architecture of the frequency measurement system is designed, and based on this architecture, the hardware circuit of the high-precision frequency measurement system using FPGA is completed. An embedded software is also designed, which includes modules for frequency measurement, communication, and firmware programming. This software enables the integration of the high-precision frequency measurement system based on FPGA and its application in carbon dioxide gas concentration detection using QCM. Experimental results show that the absolute error of the frequency system measurement does not exceed 0.35Hz, with an average error of 0.268Hz and a maximum relative error of 3.5×10^-8. The frequency measurement resolution can reach 0.1Hz. The system exhibits low measurement error and good stability, indicating a promising application prospect in carbon dioxide concentration detection based on QCM.