I/F电路线性度误差分析及补偿

Error Analysis and Compensation of I/F Circuit Linearity

在惯性导航系统中,加速度计输出的电流信号需要通过模数转换电路转换为输出脉冲。针对惯导系统中I/F模数转换电路输出脉冲与输入电流因器件不理想而存在非线性失真的问题,提出了一种二级补偿算法。该算法通过建立温度补偿模型和线性度补偿模型,对电路的线性度进行二级补偿,弥补了温度变化引起的误差,同时解决了硬件仅补偿一阶误差的问题,使模数转换电路在器件参数不理想的情况下仍能在大量程环境中保持高精度。将其应用到实际电路中,经实验验证表明,该算法能将模数转换电路的非线性指标从7.20×10^(-4)降到4.93×10^(-6),有效减少了器件不理想所带来的非线性失真。

In inertial navigation system,the current signal output by the accelerometer needs to be converted into the output pulse through the analog-to-digital conversion circuit.Aiming at the problem for nonlinear distortion due to the unsatisfactory device in output of I/F analog-to-digital conversion circuit in inertial navigation system,a two-stage compensation algorithm is proposed in this paper.In this algorithm,temperature compensation model and linearity compensation model are established to compensate the linearity of the circuit,the error caused by temperature change is compensated,and the problem that the hardware only compensates the first-order error is solved,which makes the analog-to-digital conversion circuit maintain high-precision in large range environment even if the device parameters are unsatisfactory.The algorithm is applied to the practical circuits,and the experiment results show that this algorithm can reduce the nonlinear index of I/F analog-to-digital conversion circuit from 7.20×10^(-4)to 4.93×10^(-6),and effectively decrease the nonlinear distortion caused by the unsatisfactory device.