Influence of frequency mixing on vibration test of fiber optic gyroscope

Frequency mixing happening in vibration test on fiber optic gyroscope (FOG) can cause signal distortion of the output of FOG, which will influence the test result. In order to verify the consequence of frequency mixing and restrain it, a closed-loop data acquisition system which was used to get the original output of FOG (namely closed-loop data) was designed and realized (the speed could reach 1 MHz×16 bit). The character of closed-loop data in vibration test was analyzed and the fact that the vibration error could not be wiped out by filter was known, which would cause frequency mixing if the sampling frequency was not proper. The frequency mixing was verified through simulation by matlab and vibration test on FOG. The restraining method of frequency mixing was given. Experiments show that for the FOG whose data acquisition process was designed as what was referred, the design improved could avoid frequency mixing very well.