CN201837484U - Temperature measuring device based on Raman light reaction - Google Patents

Abstract

The utility model relates to a temperature measuring device based on Raman light reaction. The device injects laser lights to an optical fiber through a laser; lights reflected by the optical fiber are subjected to filtering isolation, so as to obtain Stocks lights and anti-Stokes lights; after photovoltaic conversion and amplification, the two beams of light enter an analog-digital conversion module to be sampled; sampled data is fed to an FPGA (Field Programmable Gate Array) to be subjected to real-time accumulating filtering; filtered electrical signals enter an embedded processor; the embedded processor compares the received electrical signals to electrical signals input by an electronic temperature measuring sensor, so as to obtain the temperature in the position of reflected light; and parameter adaptive optimization is conducted to a temperature demodulating formula through positions and temperature values of four electronic temperature sensing sensors. The device has the characteristics that the speed for processing signals, such as filtering signals and the like, is very fast, temperature distortion is small, a system has a self-adapting function to the environment, and the reliability of the system is improved.

Description

Temperature measuring equipment based on the Raman light reflection

Technical field

The utility model relates to a kind of temperature measuring equipment based on the Raman light reflection, is mainly used in length and measures apart from real time temperature.

Background technology

Optical fiber technology is the new technology of fast development over nearly 20 years, the distributing optical fiber sensing technology is the bright spot of current optical fiber in industrial detection is used, based on the temperature detection of Raman reflection, the amplitude of the Raman light of its reflected back and the height of ambient temperature have more significantly relation.Positional information under a certain temperature then can be recorded by catoptrical time of return.Like this, can obtain temperature and positional information by the catoptrical amplitude of continuous acquisition.

After based on Raman in time-domain reflection optical, anti-Stokes (AN-STROKES) and Stokes (STROKES) light all and temperature correlation, wherein anti-Stokes is especially responsive to temperature.But a common feature is that these catoptrical light intensity are very faint, therefore must carry out enhancement process to reflected signal.Method commonly used be repeatedly progressive mean to overcome interference, accumulative frequency will surpass ten thousand times usually just can have effect preferably.

Expect the effective information of long distance, each sampled point must increase.When a light pulse when an end-fire of optical fiber is gone into optical fiber, this light pulse meeting is propagated forward along optical fiber, every bit in the air all can produce reflection, and a fraction of catoptrical direction just in time opposite with the incident direction of light (also can be described as " dorsad ") is arranged among the reflection.The temperature of the reflection spot in this back-reflection light intensity and the optical fiber has certain correlationship.Light is propagated needs the time, just can estimate the source position of coming of reflection like this to the catoptrical moment by recorder.For fixing digital sample of sampling period, this time correspondence be exactly counting of sampled point.Such as in the Raman detection system, STROKES and AN-STROKES light are very faint, adopt the 100M sampling, and measuring distance reaches 10km, and 10000 points are wanted in each sampling, and 10,000 samplings are exactly 100,000,000 one points.

Traditional way is the signal that collects to be sent into carry out accumulation process in microcomputer or the microprocessor, but because the influence of transmission and arithmetic speed must add buffer memory, and every batch data must leave time enough at interval with following batch data.Like this, average as carrying out ten thousand times, will consume for a long time, the real-time of detection is had a greatly reduced quality.

In addition, the calibration of Raman distributed temp measuring system normally utilizes calibration cell to calibrate in the chamber before use by experiment, and in actual application environment, the environmental factor during owing to extraneous factor and calibration may have than big-difference, thereby causes measuring result error bigger.

Publication number is the Chinese patent " long-range 30 kilometers profile fiber Raman temperature sensor systems " of CN 1444026A, publication number is the Chinese patent " very-long-range distributed fiber Raman and Brillouin's photon sensor " of CN101162158A, publication number is the Chinese patent " the very-long-range distributed type optical fiber Raman photon temperature sensor of integrated raman amplifier " of CN101162175A, what these three patents adopted is high-speed collection card collection, repeatedly the data of Cai Jiing must be stored earlier then and just can be handled, speed is slow, cause the response time obviously to lag behind, the algorithm in later stage mainly relies on computing machine to finish, be not easy to realize parallel processing, very flexible.

The utility model content

Bigger at former distributed temperature measuring instrument volume, can't self-adaptation calibrate, and the response time wait shortcoming more slowly, the utility model provides temperature measuring equipment to save calibration cell, the microcomputer case, and volume dwindles significantly, the temperature that records by near electronic temperature sensor additional optical fiber top as a reference, automatically carry out parameter calibration, the filtering signal processing speed is fast, temperature measuring equipment and method based on the Raman light reflection that the temperature distortion is little.

For achieving the above object, the utility model adopts following technical scheme:

Based on the temperature measuring equipment of Raman light reflection, it comprises:

Flush bonding processor, it controls laser beam emitting device, receives the filtering signal from filter output;

Laser beam emitting device, it accepts flush bonding processor control, and output laser is to WDM device;

WDM device is isolated and filtering light signal, isolates stroke light and anti-stroke light;

Optical processing device is converted to electric signal with light signal;

Filter processing carries out to electric signal that high speed adds up and average filter;

The electronic temperature measurement module is measured the temperature at optical fiber top and is used for demarcation;

Flush bonding processor is connected with the laser beam emitting device input end, and the laser beam emitting device output terminal is connected with the WDM device input end; WDM device is communicated by letter with optical fiber bidirectional; The light signal of WDM device output simultaneously enters filter processing after opto-electronic conversion, the output terminal of filter is connected with the input end of flush bonding processor.

Described laser beam emitting device comprises drive circuit for laser and laser instrument; Drive circuit for laser is connected with laser instrument with processor respectively; Described laser instrument is connected with WDM device; Laser instrument is the Distributed Feedback Laser of centre wavelength 1550nm, peak power 20W.

Described flush bonding processor is process chip or the dsp chip or the single-chip microcomputer of Embedded Operating System; Described WDM device is a light wavelength division multiplexing, and its output center wavelength is respectively 1450nm and 1663nm, and live width is 10nm; Described optical processing device is avalanche photodide APD.

Described filter processing is an on-site programmable gate array FPGA, and FPGA comprises two totalizers and two RAM data storage blocks, and wherein totalizer is 32.

Described electronic temperature measurement module is four electronic type temperature probes, is articulated in the initiating terminal of optical fiber, the distance to a declared goal of being separated by between four electronic temperature measurement sensors.

Based on the temp measuring method of Raman light reflection, it comprises the steps:

Step1: by the flush bonding processor output pulse signal to drive circuit for laser;

Step2: drive circuit for laser produces short duration current signal drive laser;

Step3: to optical fiber injected pulse laser, the reflected light behind fiber reflection obtains Stokes and anti-Stokes light through light wavelength division multiplexing filtering to laser instrument by the light wave multiplexer;

Step4: Stokes and anti-Stokes light through opto-electronic conversion and after amplifying, enter the high speed analog-to-digital conversion module respectively and sample respectively;

Step5: the data after the sampling are sent into the FPGA filtering that adds up in real time respectively, and filtered current signal enters flush bonding processor respectively;

Step6: the temperature value of two-way current signal that the flush bonding processor utilization receives and the input of electronic type temperature probe carries out parameter calibration, obtains the temperature of optical fiber respective point according to the calibration value of parameter;

Step7: the temperature value to the optical fiber respective point that records carries out error correction.

The process of demarcating among the described step6 is as follows:

1) temperature at the two-way current signal in the optical fiber somewhere that receives of flush bonding processor and this place satisfies:

$\frac{1}{T}=c_1[\ln \left(\frac{I_1-d_a}{I_2-d_s}\right)+c_2]---\left(1\right)$

Wherein,

λ _s, λ _aBe respectively Stokes and Anti-Stokes optical wavelength; H is a Planck's constant; C is the light velocity in the vacuum; K is a Boltzmann constant; Δ γ is the skew wave number; T is the temperature in optical fiber somewhere; I ₁, I ₂Be respectively the current value of Anti-Stokes light and Stokes light correspondence, d _a, d _sBe respectively the direct current biasing of Anti-Stokes and Stokes light correspondence;

2) establish the temperature that 4 electronic type temperature probes measure and be respectively T ₁, T ₂, T ₃, T ₄, utilize the formula in the step 1) to obtain with the temperature at the optical fiber place of electronic type temperature probe co-located, obtain following system of equations simultaneously accordingly:

$\left\{\begin{array}{c}\frac{1}{T_1}=c_1[\ln \left(\frac{I_{11}-d_a}{I_{12}-d_s}\right)+c_2]\\ \frac{1}{T_2}=c_1[\ln \left(\frac{I_{21}-d_a}{I_{22}-d_s}\right)+c_2]\\ \frac{1}{{\mathrm{<figure-callout\; id="3"\; label="T"\; filenames="HDA0000027352740000041.png"\; state="\{\{state\}\}">T</figure-callout>}}_3}=c_1[\ln \left(\frac{I_{31}-d_a}{I_{32}-d_s}\right)+c_2]\\ \frac{1}{T_4}=c_1[\ln \left(\frac{I_{41}-d_a}{I_{42}-d_s}\right)+c_2]\end{array}\right.---\left(2\right)$

Wherein, I ₁₁, I ₂₁, I ₃₁, I ₄₁For Anti-Stokes light with the corresponding current value in optical fiber place of 4 electronic type temperature probe co-located; I ₁₂, I ₂₂, I ₃₂, I ₄₂For Stokes light with the corresponding current value in optical fiber place of 4 electronic type temperature probe co-located;

3) system of equations in the step (2) is adopted the BROYDEN solution by iterative method, obtain c ₁, c ₂, d _a, d _sCalibration value;

4) with parameter c ₁, c ₂, d _a, d _sCalibration value and the pairing I in optical fiber somewhere ₁, I ₂Formula in the current value substitution step 1) obtains optical fiber temperature value herein.

To carry out the process of error correction as follows for temperature among the described step7:

A. the measured temperature with 4 electronic type temperature probes is designated as T respectively ₁, T ₂, T ₃, T ₄, be respectively T with the temperature at the optical fiber place of 4 electronic type temperature probe co-located ₁', T ₂', T ₃', T ₄', then square error ε can be expressed as:

ε＝(T ₁-T ₁′) ²+(T ₂-T ₂′) ²+(T ₃-T ₃′) ²+(T ₄-T ₄′) ²

B. when ε surpasses setting range, demarcate again, and obtain the temperature in optical fiber somewhere once more, realize the temperature correction.

Principle of the present utility model: send initial order by embedded controller, and output frequency is that the pulse signal of 10KHZ is to drive circuit for laser, by drive circuit for laser this waveform is carried out shaping, forming width is the short duration current signal driving Distributed Feedback Laser of 10ns.Injecting wavelength by laser instrument to optical fiber is the pulse laser of 1550nm, the light that returns through fiber reflection obtains strokes (Raman stokes light) and a-strokes (Raman anti-Stokes light) through WDM filtering (wavelength-division multiplex filtering), light is sent into avalanche type photoelectric commutator (APD) light intensity signal is converted to corresponding current signal, be voltage through trans-impedance amplifier with current conversion again, send in the high-speed AD after the two-stage wideband amplification circuit amplifies this voltage signal then and sample, the digitized voltage Value Data that obtains of sampling is sent into FPGA, by the FPGA filtering that adds up in real time.The temperature signal that filtered signal and electronic temperature measurement sensor is input to flush bonding processor is demarcated, and determines the temperature at reflected light place.

The beneficial effects of the utility model: utilize 4 detected temperature values of electronic sensor in the utility model as a reference, adopt and temperature is corrected in real time, temperature is demarcated automatically based on the minimum mean square error criterion algorithm.The utility model has made full use of high speed and the parallel characteristics of FPGA, computational data adding up and storing in data acquisition, the time of adding up and storing and collecting these data of finishing several ten thousand times is synchronous, elapsed time in addition not, need not to leave the time interval between every batch data, shorten operation time greatly, satisfied the real-time requirement that detects.

Description of drawings

Fig. 1 device synoptic diagram of the present utility model;

Fig. 2 system works flow process of the present utility model figure;

Fig. 3 electronic temperature sensor arrangenent diagram;

Functional module among Fig. 4 FPGA;

Fig. 5 amplification circuit diagram;

Fig. 6 FPGA The pipeline design synoptic diagram;

The connecting circuit figure of Fig. 7 AD sampling A and FPGA;

Wherein, 1 laser instrument, 2 drive circuit for laser, 3 human-machine interface modules, 4 communication interfaces, 5 electronic type temperature probes, 6 wavelength division multiplexers, 7 flush bonding processors, 8 thermometric optical fiber, 9APD, 10 wideband amplification circuits, 11 high-speed AD, 12FPGA.

Embodiment

Below in conjunction with embodiment and accompanying drawing the utility model is further described:

As shown in Figure 1, a kind of temperature measuring equipment based on the Raman light reflection, it comprises flush bonding processor 7, and flush bonding processor 7 is connected with drive circuit for laser 2 input ends, and drive circuit for laser 2 is connected with laser instrument 1; Laser instrument 1 is connected with wavelength division multiplexer (WDM) 6.WDM and 8 two-way communications of thermometric optical fiber; The light signal of WDM output simultaneously enters FPGA12 and carries out Filtering Processing after opto-electronic conversion.

Laser instrument 1 is selected the Distributed Feedback Laser of centre wavelength 1550nm for use in the utility model, and peak power is 20W; In order to obtain enough spatial resolutions, the drive circuit for laser 2 that adopts 10ns is the drive current as laser instrument, to obtain the pulse laser that width is 10ns.Driving circuit periodically produces the pulse current that width is 10ns, and the cycle that this pulse occurs is by flush bonding processor 7 controls.

But the flush bonding processor 7 in the utility model can be the process chip of Embedded Operating System, also can be dsp chip or single-chip microcomputer, produces the recurrent pulse that triggers drive circuit for laser 2 by this processor, and its frequency is the frequency of driving circuit output pulse.

Human-machine interface module 3 can be made up of button, LCD or touch-screen etc., the main information interchange that realizes artificial and equipment.

Communication interface modules 4 provides this device and miscellaneous equipment such as computing machine, common network, and the interface of external memory device etc. can be USB, RS232,485, the combination of one or more in Ethernet interface and the CAN bus interface.

The electronic temperature measurement module is made up of four electronic type temperature probes 5, be articulated in from the very near position of optical fiber initiating terminal, the spacing of each electronic type temperature probe is general selects 10 meters, from the nearest sensor of optical fiber starting point, its apart from the distance of initiating terminal in 0～5 meter, as shown in Figure 3, this device is positioned at the aluminium alloy cabinet, and the aluminium alloy cabinet is used to shield external interference.Each electronic type temperature probe temperature is to external world responded to, and it is become corresponding electric signal, as voltage or electric current, and has higher precision and resolution, in order to substitute the calibration cell in the traditional distributed thermometric.

Wavelength division multiplexer (WDM) 6 adopts optical fiber to merge and draws the manufacturing of awl technology, its output center wavelength is respectively 1450nm and 1663nm, and live width is 10nm, and its effect has two, the firstth, incident light and reflected light are isolated, the secondth, reflected light is carried out the light signal that filtering obtains required wavelength.The WDM that uses in the utility model has four splicing ears, is respectively light inputting end, and laser output links to each other with optical fiber by it; A common port links to each other with thermometric optical fiber; Two bright dipping ends, output center wavelength is 1663 and 1450 reflected light respectively.

APD 9 is high-speed wideband avalanche photodides, its effect is that light intensity signal is converted to corresponding electric signal, avalanche photo diode (APD) has the fast characteristics of high-gain, high sensitivity and response speed, thereby becomes the preferred signal sensitive detection parts in the laser space communication.The output signal of APD 9 enters wideband amplification circuit 10, and the broadband high power amplifying circuit of being made up of two stage amplifer is enlarged into the voltage signal of 0～5v with the signal of APD output, and wherein the two-stage amplifying circuit is selected MAX4305 high speed amplifier chip, its circuit such as Fig. 5 for use.Avalanche diode D1 is converted to current signal with light signal among Fig. 5, and at amplifier the 6th pin output voltage signal, through U2, the voltage signal that obtains 0～5v is amplified in U3 two-stage broadband.

Various clocks and the control signal of AD produces by fpga chip in high-speed AD and the filtration module.The connecting circuit of high-speed AD 11 sampling A and FPGA12 as shown in Figure 7, the filtering of high speed progressive mean realizes that by FPGA 12 wherein TH4513 mainly plays impedance matching.As shown in Figure 4, FPGA 12 comprises two totalizers and two RAM data storage blocks, wherein totalizer is 32, like this, no symbol AD translation data for 16, can add up more than 60,000 time, and the above AD sampling thief figure place of general 50M is no more than 12, thereby in general can accomplishes to add up for 500,000 times.

FPGA 12 adopts The pipeline design, the delay of storage data two clock period of palpus that resample, and implementation procedure is as follows: first cycle: AD data stable appearing on the data line of totalizer this moment, latch data arrives output terminal; Totalizer is carried out the operation that adds up, and storer is with the accumulation result write store of totalizer, as shown in Figure 6 simultaneously; Fetch pointer takes out data from next address and delivers to the latch input end, second period simultaneously: totalizer is carried out the operation that adds up, and writes results to the corresponding stored device; The memory access address pointer adds 1 simultaneously; Data are delivered to the latch input end; The memory write pointer adds 1.

Influences such as loss for the instability of eliminating laser tube output, fibre-optical bending, joint, improve the thermometric accuracy, in system design, adopt binary channels dual wavelength method relatively, promptly Anti-Stokes light and Stokes light are gathered respectively, utilized the ratio demodulation temperature signal of both intensity.Because Anti-Stokes light is more sensitive to temperature, thus with Anti-Stokes light as signalling channel, Stokes light is passage as a comparison, then the R (T) that concerns of strength ratio between the two and ambient temperature can be expressed by formula (1):

$R\left(T\right)=\frac{I_a}{I_s}={\left(\frac{{\mathrm{\&lambda;}}_a}{{\mathrm{\&lambda;}}_s}\right)}^4{e}^{-\frac{\mathrm{hc\&Delta;\&gamma;}}{\mathrm{kT}}}---\left(1\right)$

In the formula, I _a, I _sIt is respectively the desired electrical flow valuve that Anti-Stokes light and Stokes light obtain through photodetector; λ _s, λ _aBe respectively Stokes and Anti-Stokes optical wavelength; H is a Planck's constant; C is the light velocity in the vacuum; K is a Boltzmann constant; Δ γ is the skew wave number; T is an absolute temperature.(1) formula can be rewritten as

$\frac{1}{T}=-\frac{k}{\mathrm{hc\&Delta;\&gamma;}}[\ln R\left(T\right)+4\ln \left(\frac{{\mathrm{\&lambda;}}_a}{{\mathrm{\&lambda;}}_s}\right)]---\left(2\right)$

By formula (2) as can be seen, temperature is not directly proportional with light intensity ratio, but the inverse of temperature and light intensity ratio are similar to a kind of logarithmic curve relation.This will give to measure to demarcate and bring difficulty.

Actual I _a, I _sCan't accurately obtain,, therefore can only obtain approximate current I owing to exist direct current biasing to disturb and the ratio amplification _ab _a+ d _a, I _sb _s+ d _s, b _a, b _sBe system's enlargement factor total, i.e. the product of trans-impedance amplifier enlargement factor and two-stage broadband voltage amplifier enlargement factor to electric current.Because Anti-Stokes and Stokes light intensity differ bigger, common b _a＞b _sd _a, d _sBe each self-corresponding direct current biasing.At this moment if correct demodulation will manage to overcome direct current offset and amplify the influence that brings.

Make IX=I _ab _a+ d _a, I ₂=I _sb _s+ d _s, then (2) formula becomes

$\frac{1}{T}=-\frac{k}{\mathrm{hc\&Delta;\&gamma;}}[\ln \left(\frac{I_1-d_a}{I_2-d_s}\right)+4\ln \left(\frac{{\mathrm{\&lambda;}}_a}{{\mathrm{\&lambda;}}_s}\right)+\ln \left(\frac{b_s}{b_a}\right)]$

Order

Then (2) formula becomes

$\frac{1}{T}=c_1[\ln \left(\frac{I_1-d_a}{I_2-d_s}\right)+c_2]---\left(3\right)$

Coefficient c ₁, c ₂, d _a, d _sCan be by experimental calibration, but this is a nonlinear equation, and actual measured value inevitably is subjected to the influence of unknown disturbances, can seek best coefficient in certain scope.Suppose that 4 electronic sensor measurement results are accurately errorless, we use T ₁, T ₂, T ₃, T ₄Expression can be calculated by formula (3) with the temperature value that obtains on the optical fiber of electronic sensor co-located, and contain 4 parameter c to be found the solution in the formula ₁, c ₂, d _a, d _s, can utilize computing machine to find the solution by the BROYDEN process of iteration.

Concrete solution procedure is as follows:

The temperature of A. establishing 4 electronic type temperature probes measurements is respectively T ₁, T ₂, T ₃, T ₄, utilize the formula in the step 1) to obtain with the temperature at the optical fiber place of electronic type temperature probe co-located, obtain following system of equations simultaneously accordingly:

$\left\{\begin{array}{c}\frac{1}{T_1}=c_1[\ln \left(\frac{I_{11}-d_a}{I_{12}-d_s}\right)+c_2]\\ \frac{1}{T_2}=c_1[\ln \left(\frac{I_{21}-d_a}{I_{22}-d_s}\right)+c_2]\\ \frac{1}{{\mathrm{<figure-callout\; id="3"\; label="T"\; filenames="HDA0000027352740000041.png"\; state="\{\{state\}\}">T</figure-callout>}}_3}=c_1[\ln \left(\frac{I_{31}-d_a}{I_{32}-d_s}\right)+c_2]\\ \frac{1}{T_4}=c_1[\ln \left(\frac{I_{41}-d_a}{I_{42}-d_s}\right)+c_2]\end{array}\right.---\left(4\right)$

Wherein, I ₁₁, I ₂₁, I ₃₁, I ₄₁For Anti-Stokes light with the corresponding current value in optical fiber place of 4 electronic type temperature probe co-located; I ₁₂, I ₂₂, I ₃₂, I ₄₂For Stokes light with the corresponding current value in optical fiber place of 4 electronic type temperature probe co-located;

B. system of equations in the steps A (4) is adopted the BROYDEN solution by iterative method, at first order

$\left\{\begin{array}{c}y\left(1\right)=\frac{1}{T_1}-c_1[\ln \left(\frac{I_{11}-d_a}{I_{12}-d_s}\right)+c_2]\\ y\left(2\right)=\frac{1}{T_2}-c_1[\ln \left(\frac{I_{21}-d_a}{I_{22}-d_s}\right)+c_2]\\ y\left(3\right)=\frac{1}{T_3}-c_1[\ln \left(\frac{I_{31}-d_a}{I_{32}-d_s}\right)+c_2]\\ y\left(4\right)=\frac{1}{T_4}-c_1[\ln \left(\frac{I_{41}-d_a}{I_{42}-d_s}\right)+c_2]\end{array}\right.---\left(5\right)$

Make vectorial X=[c then ₁, c ₂, d _a, d _s], vectorial Y=[y (1), y (2), y (3), y (4)], y (1), y (2), y (3), y (4) is called the iteration reference variable, and gives initial value X ₀=[c ₁₀, c ₂₀, d _A0, d _S0];

Wherein,

b _A0, b _S0Be respectively in the circuit current conversion that Anti-Stokes and Stokes light are obtained through photodetector and be the total enlargement factor of final voltage (b generally speaking _A0Be 10 ⁸～10 ⁹V/A, b _S0Be 10 ⁷～10 ⁸V/A), i.e. the product of trans-impedance amplifier enlargement factor and two-stage broadband voltage amplifier enlargement factor; d _A0, d _S0Direct current offset value for the related circuit at Anti-Stokes and Stokes light place can obtain by the test to circuit board, at this different circuit different skews is arranged, in the utility model in circuit direct current offset value be approximately-1v.

Permissible error E is set, and (scope of permissible error is 1.0 * e generally speaking ^-3～1.0 * e ^-6), iterate to up to X _I+1-X _iIteration finishes during≤E, at this moment X _I+1Be the c that asks ₁, c ₂, d _a, d _sCalibration value;

C. with parameter c ₁, c ₂, d _a, d _sCalibration value and the pairing I in optical fiber somewhere ₁, I ₂Current value substitution formula (3) obtains optical fiber temperature value herein.

D. the measured temperature with 4 electronic type temperature probes 5 is designated as T respectively ₁, T ₂, T ₃, T ₄, be respectively T with the temperature at the optical fiber place of 4 electronic type temperature probe 5 co-located ₁', T ₂', T ₃', T ₄', then square error ε can be expressed as:

ε＝(T ₁-T ₁′) ²+(T ₂-T ₂′) ²+(T ₃-T ₃′) ²+(T ₄-T ₄′) ²

When ε surpasses setting range (general range is 10～20), again to c ₁, c ₂, d _a, d _sValue utilize the process among the step B to demarcate, according to calibrated c again ₁, c ₂, d _a, d _sValue can obtain the temperature in optical fiber somewhere once more, realize the temperature correction.As shown in Figure 2.Like this, no matter how measurement environment changes, parameter also will change, and reach the purpose that self-adaptation is adjusted.

Claims (5)

1. based on the temperature measuring equipment of Raman light reflection, it is characterized in that it comprises:

Flush bonding processor, it controls laser beam emitting device, receives the filtering signal from filter output;

Laser beam emitting device, it accepts flush bonding processor control, and output laser is to WDM device;

WDM device is isolated and filtering light signal, isolates stroke light and anti-stroke light;

Optical processing device is converted to electric signal with light signal;

Filter processing carries out to electric signal that high speed adds up and average filter;

The electronic temperature measurement module is measured the temperature at optical fiber top and is used for demarcation;

Flush bonding processor is connected with the laser beam emitting device input end, and the laser beam emitting device output terminal is connected with the WDM device input end; WDM device is communicated by letter with optical fiber bidirectional; The light signal of WDM device output simultaneously enters filter processing after opto-electronic conversion, the output terminal of filter is connected with the input end of flush bonding processor.

2. the temperature measuring equipment based on the Raman light reflection as claimed in claim 1 is characterized in that described laser beam emitting device comprises drive circuit for laser and laser instrument; Drive circuit for laser is connected with laser instrument with processor respectively; Described laser instrument is connected with WDM device; Laser instrument is the Distributed Feedback Laser of centre wavelength 1550nm, peak power 20W.

3. the temperature measuring equipment based on the Raman light reflection as claimed in claim 1 is characterized in that described flush bonding processor is process chip or the dsp chip or the single-chip microcomputer of Embedded Operating System; Described WDM device is a light wavelength division multiplexing, and its output center wavelength is respectively 1450nm and 1663nm, and live width is 10nm; Described optical processing device is avalanche photodide APD.

4. the temperature measuring equipment based on the Raman light reflection as claimed in claim 1 is characterized in that described filter processing is an on-site programmable gate array FPGA, and FPGA comprises two totalizers and two RAM data storage blocks, and wherein totalizer is 32.

5. the temperature measuring equipment based on the Raman light reflection as claimed in claim 1 is characterized in that described electronic temperature measurement module is four electronic type temperature probes, is articulated in the initiating terminal of optical fiber, the distance to a declared goal of being separated by between four electronic temperature measurement sensors.

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