Digital modulation argument adjusting instrument of optical fibre gyro based on FPGA

Abstract

A amplitude adjustment device of degital optical circulator based on the FPGA is disclosed, the light come from the light source (S1) is incidengted into the coupler (S3), and two beams are obtained via the coupler (S3), one of the two beams is merotomized into two beams each of which is incidengted into the two ends of the fibre-optical ring (S5) via the optical waveguide modulator (S4), the two beams are synthesized into one beam and interference after one loop circulating the fibre-optical ring (S5) and passing through the optical waveguide modulator (S4); then the beam is incidengted into the detector (S2) via the coupler (S3), the electrical signal which expresses the optical power passes the front amplifying circuit (E1) to be enlarged and filted after the conversion in detector (S2), passes the A / D converter (E2) to complete the analogue / digital conversion to output the degital signal to the signal processing module (E3) which outputs the degital modulating signal to D / A converter (E4), the analog signal outputed is enlarged by the modulation amplifying circuit (E5) and is outputed to the optical waveguide modulator (S4). The invention makes the output voltage alignment circuit of the modulating step wave integrated just in one chip of FPGA processor, not getting involved in the simulation model. The attitude of the square wave uses the digital shift mode directly and is gained from the step wave resetting voltage. The square wave and the step wave is added directly in digital-sum in FPGA instead of adding in analog add circuit.

Description

technical field [0001] The present invention relates to a device for adjusting the modulation amplitude of a fiber optic gyroscope, more particularly, a device for adjusting the modulation amplitude of an interferometric closed-loop fiber optic gyroscope based on an FPGA for the generation of a modulated step wave. Background technique [0002] In the closed-loop feedback process of the fiber optic gyroscope, it is necessary to use a ladder wave for feedback modulation, so that the reset voltage V of the ladder wave output F equal to the 2π phase voltage V of the integrated optical modulator PR , and the square wave voltage V S equal to Phase voltage . Due to the 2π phase voltage V of each integrated optical modulator PR There are differences, in the process of using V PR will also change, so the feedback modulation circuit of the fiber optic gyroscope is required to be able to adjust the reset voltage V of the ladder wave F and square wave voltage V S , so that th...

AI Technical Summary

Problems solved by technology

Due to the analog approach, additional noise and offset errors are introduced

At the same time, since the reference voltage of the D / A converter is constantly changing, the stability of the D / A converter is reduced, and the conversion error is also increased.

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