Electrical crosstalk of modulation signal in digital closed-loop FOG

The electrical crosstalk error of modulation signal in a digital closed-loop fiber optic gyroscope (FOG) is proposed by analyzing saw-tooth modulation signal, dead band, periodic noise and bias drift in a low rotational speed. The electrical crosstalk between phase modulator and photodetector and modulation error from the modulation signal are the main interference sources causing electrical crosstalk error of modulation signal. A model of the electrical crosstalk error of modulation signal is developed, based on an ideal FOG model and an interfering channel model simplified to proportional component and partial integration component. A condition expression of dead band and an expression of output error produced by periodic noise and bias drift in a low rotational speed are derived from the model of the electrical crosstalk error of modulation signal. The magnitude and frequency of the periodic noise and the magnitude and bandwidth of the FOG output are calculated. The model of the electrical crosstalk error of modulation signal is identified by its simulation results and experimental results.