基于Sigma-Delta调制技术的高精度数字磁通门磁强计仿真

Simulation Research on Precision Digital Fluxgate Magnetometer Based on Sigma-Delta Modulation Technology

设计了一种基于1 bit Sigma-Delta环路调制技术的高精度数字磁通门磁强计,建立了数字磁强计信号处理仿真模型,并利用Matlab的Simulink仿真工具开展了数字磁通门磁强计模型的仿真分析,对数字磁强计系统的噪声、线性度、响应速度和频率响应进行了仿真计算。利用本文1 bit Sigma-Delta环路调制技术的数字磁强计在量程超过±10^(5 )nT的情况下,系统在1 Hz处的噪声仅为4.66 pT·Hz^(-1/2),最大线性偏差为0.16 nT,动态响应速度达到2×10^(6) nT·s^(–1),频率响应带宽超过10 Hz。仿真结果表明,基于1 bit Sigma-Delta环路调制技术的数字磁通门磁强计可以有效降低对A/D转换器精度的要求,在保证性能的前提下大幅度降低了电路复杂程度,提高了系统的可靠性,在深空探测、空间磁场测量等领域具有广泛的应用前景。

A precision digital fluxgate magnetometer was designed based on Sigma-Delta modulation technology.Signal processing simulation model is carried out with Simulink tools in Matlab,simulation analysis of magnetometer characteristics is given,including the noise,linearity,response speed and frequency characteristic.The simulation results show that the measurement range of 1 bit digital magnetometer could reach more than±10^(5) nT to cover Earth magnetic field,system noise is lower than 4.66 pT·Hz^(–1/2) at 1 Hz which means the resolution is sufficient for deep space magnetic field exploration.The maximum nonlinear error is 0.16 nT and the dynamic response speed reaches 2×10^(6) nT·s^(–1) and the efficient Bandwidth is higher than 10 Hz.The simulation results indicate that 1bit digital fluxgate magnetometer could effectively reduce the critical requirements of the accuracy on the A/D converter,simplify the analog signal processing electrical circuit and improve the system reliability.The performance of 1 bit Sigma-Delta digital magnetometer indicates its impressive advantages over traditional magnetometers and wide application prospects in the field of deep space exploration and space magnetic field measurement.