Phase type distance measuring device and method based on double electro-optical heterodyne modulation

Abstract

The invention discloses a phase type distance measuring device and method based on double electro-optical heterodyne modulation, the measuring device comprises an optical path unit, a signal generation module, a signal conditioning and acquisition module and a digital processing system, the optical path unit comprises a laser, a first electro-optical intensity modulator, a circulator, an optical fiber probe and a second electro-optical intensity modulator; the laser, the first electro-optic intensity modulator and the circulator are sequentially connected through optical fibers; the circulator is respectively connected with the optical fiber probe and the second electro-optic intensity modulator through optical fibers, and the emitting direction of the optical fiber probe is over against a to-be-detected target; the signal generation module is respectively connected with the first electro-optic intensity modulator, the second electro-optic intensity modulator and the A / D analog-digital signal converter; the signal conditioning and acquisition module comprises a photoelectric conversion device, an amplification circuit, a filter circuit and an A / D analog-digital signal converter which are connected in sequence.

Description

technical field [0001] The invention belongs to the field of non-contact distance measurement. Specifically, the present invention relates to a laser phase-type distance online measurement method and device, in particular to a distance online measurement method and device using an electro-optical modulator to realize secondary heterodyne modulation of the amplitude of an optical signal. Background technique [0002] Precision ranging technology has a wide range of application requirements in advanced technologies and cutting-edge scientific fields such as national defense and military industry, aerospace, etc., especially in the manufacturing of large-scale precision machinery and the assembly of major rotating equipment. Play an important role. On-line measurement of the internal clearance of major equipment is an important part of equipment health management and the key to ensuring work efficiency and operation safety. Typical equipment clearances include axial clearance ...

AI Technical Summary

Problems solved by technology

In the traditional distance measurement method, the pulse method is limited by the switching time of transmitting and receiving, and there is a ranging blind zone, and the measurement accuracy cannot meet the requirements of precise ranging; the measurement accuracy of the frequency method is limited by the frequency difference of frequency modulation, and the ranging accuracy is not good at submillimeter distances. High, and limited by the sweep rate, the measurement response speed is low, and it is difficult to apply to the tip clearance measurement; the phase method modulates the intensity of the laser signal, and realizes the distance measurement by comparing the phase of the measurement optical signal and the reference optical signal; the previous proposal The "Dynamic Measuring Device and Method for Axial Gap of Rotor-Stator Based on Phase-based Laser Ranging" (202110464019.1) adopts the principle of electrical down-conversion, uses photoelectric conversion devices to directly receive the return light signal, and its light intensity modulation frequency is in the microwave frequency band. The bandwidth performance requirements of photoelectric conversion devices are extremely high, and due to the constraints of the gain-bandwidth product of the preamplifier, the signal-to-noise ratio of the output electrical signal is poor

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