Eigen frequency of fiber optic gyro (FOG) is determined by the length of fiber coil. Since the length cannot be controlled accurately while winding, timing generator should trace the eigenfrequency expediently without modification of hardware. The influences of veracity and stabilization of modulation-demodulation signal on the scale factor of FOG was analyzed through the theory of correlation-based measurement. One chip of field programmable gate arrays (FPGA) was used to generate three timings of miniaturized three-cluster FOG within resourceconstraints, and the capacity of frequency tracing was calculated within the eigenfrequency range of middle precision FOG. Experimental results indicate that the timing scheme satisfied the requirement of miniaturized three-cluster FOG to modulation-demodulation signal.