Modulation and demodulation circuit of fiber option gyroscope (FOG) open-loop signal

Abstract

The invention discloses a modulation and demodulation circuit of fiber option gyroscope (FOG) open-loop signals. The circuit adopts a monolithic LVDT integrated circuit (IC) for modulating and demodulating an FOG open-loop signal, generating a sinusoidal signal, synchronously detecting and dividing one odd harmonic amplitude and one even harmonic amplitude and acquiring the tangent value of a mobile signal phase by low-pass filtration. The invention uses the monolithic LVDT IC to realize the four functions, i.e., sinusoidal signal generation of a drive phase modulator, synchronous detection, the elimination of light-source light-intensity fluctuation influence and low-pass filtration and greatly simplify a signal-processing circuit; the monolithic LVDT IC outputs the tangent value of a mobile signal phase so that when the phase increases and trends to pi / 2, the tangent value bends upwards, does not trend to saturation and reduces the error of a complementary tangent operation; and a division operation is internally realized by the monolithic LVDT IC so that a digital signal processor at a high price can be replaced by a monolithic computer at a low price for non-linear corrosion.

Description

technical field [0001] The invention relates to a gyroscope, in particular to an optical fiber gyroscope open-loop signal modulation and demodulation circuit. Background technique [0002] The existing fiber optic gyroscope open-loop signal modulation and demodulation circuit such as figure 2 . Optical part 1 of fiber optic gyro consists of light source 1.1, source beam splitter 1.2, fiber optic polarizer 1.3, ring beam splitter 1.4, fiber optic sensing ring 1.5, phase modulator 1.6 and photodetector 1.7; sinusoidal signal source 8 drives the optical The phase modulator 1.6 in the part 1, the photodetector 1.7 in the optical part 1 output the rotational electrical signal of the gyroscope relative to the inertial reference frame, and its signal contains each harmonic component of the frequency of the sinusoidal signal source 8, wherein the odd harmonic The amplitude of the wave signal is proportional to the sine value of the rotation signal phase; the amplitude of the even ...

AI Technical Summary

Problems solved by technology

This kind of open-loop signal modulation and demodulation circuit has the following disadvantages: there are many unit circuit devices and low reliability; a digital signal processor with a higher price is required; because the first harmonic is the sine value of the rotating signal phase, when the phase increases and When it tends to π / 2, the sine value bends and tends to be saturated, and the error of arcsine operation increases

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