Implementation method free of calibration of modulated spectrum

A technology for modulating spectrum and implementing methods, which is applied in the field of optical measurement, can solve problems such as deviation and change of measurement results, achieve the effect of simplifying requirements, complete algorithm functions, and reducing the amount of simulation calculation

Inactive Publication Date: 2014-06-11
PLA PEOPLES LIBERATION ARMY OF CHINA STRATEGIC SUPPORT FORCE AEROSPACE ENG UNIV
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  • Application Information

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Problems solved by technology

Although the initial light intensity can be measured in advance, in the environment with severe interference, the attenuation caused by many non-absorbing factors will cause the initial light intensity to change significantl...

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  • Implementation method free of calibration of modulated spectrum
  • Implementation method free of calibration of modulated spectrum
  • Implementation method free of calibration of modulated spectrum

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Embodiment Construction

[0023] specific implementation plan

[0024] The implementation method of the calibration-free modulation spectrum of the present invention will be further described in detail in conjunction with the accompanying drawings and examples. figure 1 A flow diagram of the invention is given.

[0025] The implementation method of the calibration-free modulation spectrum of the present invention, the implementation steps are as follows:

[0026] Step 1. Digital phase-locked signal demodulation

[0027] The first step in the implementation of the calibration-free modulation spectrum is to use the digital phase-locking algorithm to process the detection signal, which is divided into five tasks. The implementation plan is as follows:

[0028] ①. Acquisition of measurement signals

[0029] Measurement signal acquisition, read and detect photoelectric signals by data acquisition equipment (such as data acquisition card), sampling rate f 1 and data length L. The detection photoelectric...

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Abstract

The invention provides an implementation method free of calibration of a modulated spectrum by adopting a wavelength modulation technology suitable for a severe environment based on a tunable diode laser absorption spectrum. The method comprises the following steps: demodulating digital phase locking signals, simulating the modulated spectrum and extracting measurement parameters. The concrete content of the method comprises the following steps: demodulating photoelectrical signals by utilizing a digital phase locking algorithm to obtain harmonic signals; obtaining a simulation database of the harmonic signals through accurate theoretical calculation; extracting the flow field speed, temperature and component concentrations by combining the harmonic signals with the simulation database.

Description

technical field [0001] The invention belongs to the technical field of optical measurement, relates to methods such as signal processing and numerical simulation, and is a universal and reliable measurement method developed for the absorption spectrum measurement of gas phase molecules. Background technique [0002] Optical measurement technology has been widely used in scientific research experiments, environmental monitoring and combustion field diagnosis. Absorption spectroscopy theoretically needs to measure the light intensity information before and after absorption at the same time to obtain the absorption information of molecules. In practical applications, methods such as reference beam or function fitting are often used to determine the light intensity before absorption, that is, the spectral baseline. These methods are difficult to obtain accurate spectral baseline information. In addition, although the modulation method can significantly improve the signal-to-no...

Claims

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Application Information

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IPC IPC(8): G01N21/39
Inventor 洪延姬王广宇潘虎赵文涛
Owner PLA PEOPLES LIBERATION ARMY OF CHINA STRATEGIC SUPPORT FORCE AEROSPACE ENG UNIV
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