光纤陀螺抑制过调制串扰的多态方波调制方法

光纤陀螺方波调制信号引起的调制串扰会导致陀螺输出信号的不稳定，恶化阈值、标度非线性等指标。过调制技术是采用增大调制相位来抑制噪声的一种方法，根据过调制串扰的相关解调原理和模型，推导出含过调制串扰的陀螺输出表达式，指出过调制相位是影响串扰量的重要因素。针对增大过调制相位引起串扰量增加的问题，提出一种抑制过调制串扰的多态方波调制方法，利用响应余弦函数的周期性和调制波形的重复性，产生统计上相关性很小的调制信号和解调信号，在一定的延迟时间下，调制信号及串扰信号与解调信号的相关结果为0，在相关解调过程中减小串扰量。仿真和实验结果表明，该调制方法对串扰信号的抑制作用相比方波过调制提高一个数量级，陀螺的零偏稳定性和阈值指标相比方波过调制改善约40%。

Method of variable square wave modulation to restrain excessive modulation crosstalk in FOG

Crosstalk from square wave modulation signal causes output signal instability and deteriorates threshold value and scale linearity in FOG. Excessive modulation uses bigger phase to restrain noise. According to the principle of correlative demodulation and crosstalk model, the output expression of FOG containing excessive modulation crosstalk would be derived and the modulation phase is an important effect factor of crosstalk. To solve the problem that deeper modulation phase would enlarge the crosstalk, a method of variable square wave modulation was put forward to restrain the crosstalk. With periodicity of response cosine function and repeatable modulation wave, the modulation signal and demodulation signal would be generated nearly independently. The correlative demodulation result would be zero in some delay time and reduce the crosstalk amount. Simulation and experimental results indicate that this method can improve one order of magnitude of restrain effect of crosstalk compared to square wave modulation. The zero bias stability and threshold value would be improved about 40% compared with square wave excessive modulation.