基于FPGA弱小信号测量系统研究与实现

摘要

在信号测量领域,弱小信号测量应用非常广泛,但是弱小信号测量存在误差大的问题,为了解这个问题,文章提出了基于FPGA弱小信号测量系统,FPGA具有集成度高、速度快的优点,FPGA是整个测量系统的控制核心.通过FPGA内部资源实现了数字锁相放大器,这样测量信号就不受运放温漂和偏置影响;通过光耦隔离电路、二阶低通滤波器有效的提高电压信号测量的稳定性.此系统结构简单、功耗低、扩展灵活同时还可以实现在线升级.文章对测试的数据使用最小二乘法拟合曲线进行了误差分析,测试和分析的结果表明,此系统测量精度高,可以达到0.93％,能很好的应用在微弱信号测量中领域.%In the field of signal measurement,small signal measurement is widely used,but there are many errors in weak signal measurement.In order to understand this problem,this paper proposes a weak signal measurement system based on FPGA.FPGA has advantages of high integration and fast speed,and is used as the control core of the whole measurement system.FPGA internal resources are used to achieve a digital lock-in amplifier,so that the measurement signal is not subjected to operational temperature drift and bias effect.The optocoupler isolation circuit and two order low-pass filter are used to improve the stability of the measured voltage signal effectively.The system is simple,low power consumption,flexible expansion,and also can be upgraded online.Based on the test data and using the least squares fitting curve of error analysis,test and analysis results show that this system has high measurement accuracy,which can reach 0.93 ％,and can be applied in the field of weak signal measurement.