High-frequency light intensity modulated green laser weak signot distance and thickness measuring technique

A light intensity modulation, weak signal technology, applied in the direction of using optical devices, measuring devices, instruments, etc., can solve the problems of low quantum effect, low photon energy, long wavelength, etc.

Inactive Publication Date: 2004-02-18
NANJING NORMAL UNIVERSITY
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Problems solved by technology

Both of the above two instruments use red light as the light source, which has a long wavelength and low photon energy, so the quantum effect is low, especially in the distance measurement and thickness measurement without a matching target, because the optical signal received by the detector is very weak, the power is in the nW magnitude, improving its acceptance sensitivity has become a very important issue

Method used

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  • High-frequency light intensity modulated green laser weak signot distance and thickness measuring technique
  • High-frequency light intensity modulated green laser weak signot distance and thickness measuring technique

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Embodiment Construction

[0008] (1) Phase lock and frequency stabilization

[0009] The phase-locked and frequency-stabilized part provides the main vibration signal required by the entire system (frequency is f 1 ), local oscillator signal (frequency is f 2 ), and the difference frequency signal f of the main and local oscillators p . Using a temperature-compensated crystal oscillator with a stability of less than 5ppm and a frequency of 15MHz as the main oscillator, after 10,000 frequency divisions, about 1.500KHz is obtained. Use the output signal frequency f of the main oscillator 1 with the voltage control signal frequency f 2 , the sum-frequency signal f is generated after mixing 1 +f 2 , and the difference frequency signal f 1 -f 1 , filter the sum frequency with a low-pass filter, and take out the difference frequency signal f 1 -f 2 or f 2 -f 1 applied to the output of the phase detector. When the loop is stable

[0010] f 1 -f 2 =f p or f 2 -f 1 =f p

[0011] Therefore, ...

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Abstract

The range-measuring and thickness-measuring technology comprises five portions of phase-lock frequency stabilization, laser transmitting and modulation, photoelectric receiving detection, low-frequency frequency-selective amplification and shaping and phase discrimination display. Said invention adopts green laser as light sourse, as compared with red laser, in furnace lining thickness-measuring instrument it can greatly raise signal-noise ratio and measurement sensitivity, also can adopt intermodulation green laser source to make it possess small volume, low cost, high efficiency and simple structure, etc..

Description

technical field [0001] The invention relates to a distance-measuring and thickness-measuring system for modulating green laser weak signals with high-frequency light intensity, and belongs to the technical field of photoelectric detection. Background technique [0002] The weak light signal detection technology is a high-tech, which can provide a powerful test method for modern science and technology and industrial and agricultural production. It is an important application aspect of this technology to use laser for precise length measurement without matching target. For example, the furnace (bag) lining thickness gauge in the steelmaking workshop is in a high temperature environment above 1500 ° C and there is a strong background noise. To test the thickness of the furnace lining, and then draw the outline of the inner wall of the steelmaking furnace instead of visual inspection, so as to repair in time, prolong the service life of the steelmaking furnace, and achieve high...

Claims

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Application Information

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IPC IPC(8): G01B11/06
Inventor 华家宁吴栋
Owner NANJING NORMAL UNIVERSITY
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