数模转换器毛刺对光纤陀螺相关检测的影响分析

Effect of DAC Glitch on Correlation Modulation in Digital Closed-loop IFOG

数模转换器(DAC)是全数字闭环光纤陀螺反馈通道的重要部件,DAC的毛刺特性会对光纤陀螺的调制解调结果产生影响。基于DAC中值毛刺特性建立了光纤陀螺反馈回路的非理想调制方波模型,分析了调制频率与本征频率不同时DAC毛刺在干涉信号中产生的各类周期干扰信号。利用周期干扰信号的Fourier级数推导出了DAC毛刺造成调制解调误差的数学模型,仿真分析了数模转换器毛刺的宽度、高度,光纤陀螺调制频率、本征频率及放大电路的增益带宽对陀螺解调误差的影响。最后,通过开环实验验证了DAC毛刺对光纤陀螺调制解调的影响。

Digital to analog converter(DAC) is an important part of all digital closed-loop fiber optic gyroscope(FOG) feedback loop, DAC glitch will affect the result of modulation and demodulation of IFOG. The model of non-ideal modulated square wave was built according to the characteristic of mid-scale glitch, different conditions of interference signal caused by DAC glitch when the modulation frequency is not equal to eigenfrequency were analyzed. The mathematical model of modulation and demodulation errors caused by DAC glitch were formulated by applying Fourier series of periodic interference signal. Furthennore, the effects of the glitch impulse, modulation frequency, eigenfrequency and amplifier gain bandwidth on the bias error of closed-loop FOG were analyzed by simulating, and the effect of DAC glitch on modulation and demodulation was verification through open-loop experiment.