CN106052730A - Signal demodulation method and signal demodulation device used in optical fiber distributed sensor system - Google Patents
Signal demodulation method and signal demodulation device used in optical fiber distributed sensor system Download PDFInfo
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
- G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
- G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
- G01D5/353—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre
- G01D5/3537—Optical fibre sensor using a particular arrangement of the optical fibre itself
- G01D5/35377—Means for amplifying or modifying the measured quantity
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- G—PHYSICS
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- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
- G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
- G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
- G01D5/353—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre
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Abstract
The invention discloses a signal demodulation method and a signal demodulation device used in an optical fiber distributed sensor system. The method comprises the following steps: obtaining a light pulse coding sequence and a signal after convolution of the light pulse coding sequence and the impulse response of an optical fiber to be detected; transforming the obtained light pulse coding sequence and the signal after convolution to a frequency domain through Fourier transform, and calculating the impulse response of the optical fiber to be detected in the frequency domain according to the transformed light pulse coding sequence and the transformed signal after convolution; and transforming the obtained impulse response of the optical fiber to be detected in the frequency domain to a time domain through Fourier inverse transform to get the impulse response of the optical fiber. According to the signal demodulation method and the signal demodulation device used in an optical fiber distributed sensor system of the invention, primary pulse input is adopted, and there is no need to consider whether the sum of complementary gray code autocorrelation is impulse response, so demodulation error is reduced.
Description
Technical field
The invention belongs to signal demodulation techniques field, be specifically related to a kind of signal solution for distributed fiber-optic sensor system
Adjust method and device.
Background technology
Distributed fiber-optic sensor system is with light wave as transducing signal, with optical fiber as transmission medium, it is possible to outside perception and demodulation
Boundary's measurand in time with the continuous distribution information in space, owing to optical fiber itself is not charged, volume is little, light weight, pliable
Song, electromagnetism interference, radiation resistance are good, particularly can be suitable under the adverse circumstances such as inflammable, explosive and strong electromagnetic
Use so that the key areas such as it is at following intelligent grid, Oilfield Pipelines security monitoring, communication line attack early warning have extensively
Application demand.Distributed fiber-optic sensor technology is divided into based on Rayleigh scattering, based on Raman scattering, biography based on Brillouin scattering
Sense technology.
Distributed fiber-optic sensor technology develops towards farther distance sensing and higher spatial resolution both direction.
Optical pulse code is then an up an important way of system sensing distance.The core concept of optical pulse code technology, is to use
The a length of L optical pulse code sequence being made up of code element " 1 " and " 0 " of intensity modulated of specific rule (is commonly divided into
Simplex coding and complementary Gray code), replace the single pumping pulse in sensing solutions, then response solution being transferred to is bent
Line uses corresponding decoding process to be decoded, and promotes system signal noise ratio, and then extend on the premise of not changing the measurement time
Distance sensing.Optical pulse code technology is widely used in various optical fiber sensing system, such as optical time domain reflection (OTDR), Raman
Optical time domain reflection (ROTDR), Brillouin light Time Domain Reflectometry (BOTDR), Brillouin optical time domain analysis (BOTDA).
As a example by bipolarity Gray code, cataloged procedure is as follows: be L and all by two code lengths of specific law generation
The complementary Gray code light pulse sequence A being made up of code element " 1 " and "-1 "kAnd Bk.Due to light arteries and veins in OTDR, ROTDR, BOTDR
Punching can not be negative, so AkAgain by the A being made up of code element " 1 " and code element " 0 " accordinglyk1,Ak2Do difference to obtain, BkAgain by accordingly
The B being made up of code element " 1 " and code element " 0 "k1,Bk2Do difference to obtain.Can be by gain-type pulse and attenuation type pulse in BOTDA
Constitute " 1 " and "-1 " code.AkAnd BkRelation should meet:
Ak*Ak+Bk*Bk=2L δk (1)
Wherein * represents relevant operator, as shown in Figure 1.And δkRepresenting discrete impulse function, expression formula is:
The complementary Gray code light pulse sequence A that will designkAnd BkIncident optical respectively, with the impulse response h of optical fiberk
After carrying out convolution, respectively obtain two groups of different responses, i.e.With
The optical fiber impulse response h of corresponding above-mentioned cataloged procedurekDemodulating process as follows: above-mentioned two groups of different responses are divided
Not with corresponding original, complementary gray-code sequence AkAnd BkCarry out associative operation, and by two groups of response summations after associative operation,
I.e. can get the optical fiber impulse response that signal to noise ratio promotes, expression formula is:
According to the characteristic of Complementary Golay sequences, the main peak of the auto-correlation function of the two is identical, and secondary lobe is complementary.Auto-correlation letter
After number summation obtains sensing function, the amplitude of main peak doubles, and secondary lobe is cancelled out each other.
But in actual application system, as in figure 2 it is shown, the laser that laser instrument sends, by by waveform generator
(AWG) electrooptic modulator (EOM) controlled, forms the pulse after coding.After erbium-doped fiber amplifier (EDFA) amplifies,
In circulator enters testing fiber.
EDFA is when to Optical pulse amplification, for continuous print light pulse it cannot be guaranteed that identical gain is amplified, therefore at warp
After crossing EDFA, relatively after light pulse amplitude can be relatively low, occur that the symbol power of diverse location is inconsistent, as shown in Figure 3.Now difficult
To ensure formula (1), as shown in Figure 4, thus when demodulation, complementary Gray code auto-correlation sum is not impulse response but in punching
Swash the secondary lobe that response side occurs, cause measurement error.It is simulated with the impulse response of 20km optical fiber for Fig. 5.Demodulated
After, the response obtained is Fig. 6.It appeared that occur in that the biggest shake after Xie Tiao, demodulating error can be bigger.
Summary of the invention
The purpose of the embodiment of the present invention be to provide a kind of signal demodulating method for distributed fiber-optic sensor system and
Device, to reduce the demodulating error to optical fiber impulse response.
For reaching above-mentioned purpose, the embodiment of the invention discloses, a kind of signal solution for distributed fiber-optic sensor system
Tune method, comprises the following steps:
Obtain the letter after the impulse response convolution of an optical pulse code sequence and optical pulse code sequence and testing fiber
Number；
By the signal after the optical pulse code sequence obtained and convolution, respectively by Fourier transform to frequency domain, according to change
Optical pulse code sequence after changing and the signal after convolution, be calculated the impulse response of testing fiber under frequency domain；
By inverse fourier transform, the impulse response of testing fiber under frequency domain obtained is converted into time domain, obtains to be measured
The impulse response of optical fiber.
Preferably, described is calculated the impulse response of testing fiber under frequency domain, and computing formula is:Its
In, H represents the impulse response of testing fiber under frequency domain, and Y represents by the optical pulse code sequence after Fourier transform to frequency domain
Signal after the impulse response convolution of row and testing fiber, AfRepresent by the optical pulse code sequence after Fourier transform to frequency domain
Row.
Preferably, described by inverse fourier transform, the impulse response of testing fiber under frequency domain obtained is converted into
Time domain, computing formula is:Wherein, h represents the impulse response of testing fiber under time domain, and Y represents and passes through Fourier
Leaf transformation is to the signal after the impulse response convolution with testing fiber of the optical pulse code sequence after frequency domain, AfFourier is passed through in representative
Leaf transformation is to the optical pulse code sequence after frequency domain.
Preferably, the optical pulse code sequence of described testing fiber is: original optical pulse coded sequence is by mixing bait light
Fiber amplifier is amplified the optical pulse code sequence after processing.
Preferably, described original optical pulse coded sequence is: two light pulses using complementary Gray code to obtain are compiled
Any one in code sequence.
The embodiment of the invention also discloses, a kind of signal demodulating equipment for distributed fiber-optic sensor system, including,
Signal acquisition module, it is thus achieved that an optical pulse code sequence and optical pulse code sequence and the impulse of testing fiber
Signal after response convolution；
Signal conversion module, by the signal after the optical pulse code sequence obtained and convolution, passes through Fourier transform respectively
To frequency domain, according to the optical pulse code sequence after conversion and the signal after convolution, it is calculated rushing of under frequency domain testing fiber
Swash response；
Signal inverse transform module, is converted the impulse response of testing fiber under frequency domain obtained by inverse fourier transform
To time domain, obtain the impulse response of testing fiber.
Preferably, described is calculated the impulse response of testing fiber under frequency domain, and computing formula is:Its
In, H represents the impulse response of testing fiber under frequency domain, and Y represents by the optical pulse code sequence after Fourier transform to frequency domain
Signal after the impulse response convolution of row and testing fiber, AfRepresent by the optical pulse code sequence after Fourier transform to frequency domain
Row.
Preferably, described by inverse fourier transform, the impulse response of testing fiber under frequency domain obtained is converted into
Time domain, computing formula is:Wherein, h represents the impulse response of testing fiber under time domain, and Y represents and passes through Fourier
Leaf transformation is to the signal after the impulse response convolution with testing fiber of the optical pulse code sequence after frequency domain, AfFourier is passed through in representative
Leaf transformation is to the optical pulse code sequence after frequency domain.
Preferably, the optical pulse code sequence of described testing fiber is: by original optical pulse coded sequence by mixing bait
Fiber amplifier is amplified the optical pulse code sequence after processing.
Preferably, described original optical pulse coded sequence is: two light pulses using complementary Gray code to obtain are compiled
Any one in code sequence.
As seen from the above technical solutions, the embodiment of the present invention is by obtaining an optical pulse code sequence and light pulse
Signal after the impulse response convolution of coded sequence and testing fiber；By the letter after the optical pulse code sequence obtained and convolution
Number, respectively by Fourier transform to frequency domain, according to the optical pulse code sequence after conversion and the signal after convolution, it is calculated
The impulse response of testing fiber under frequency domain；The impulse response of testing fiber under frequency domain that will be obtained by inverse fourier transform
It is converted into time domain, obtains the impulse response of testing fiber.Owing to the present invention uses pulsatile once to input, no at all consider complementation
Gray code auto-correlation sum is this condition of optical fiber impulse response, therefore reduces demodulating error.
Certainly, arbitrary product or the method for implementing the present invention must be not necessarily required to reach all the above excellent simultaneously
Point.
Accompanying drawing explanation
In order to be illustrated more clearly that the embodiment of the present invention or technical scheme of the prior art, below will be to embodiment or existing
In having technology to describe, the required accompanying drawing used is briefly described, it should be apparent that, the accompanying drawing in describing below is only this
Some embodiments of invention, for those of ordinary skill in the art, on the premise of not paying creative work, it is also possible to
Other accompanying drawing is obtained according to these accompanying drawings.
Fig. 1 is to use complementary Gray code schematic diagram in background technology；
Fig. 2 is the application system figure of signal demodulation in background technology；
Fig. 3 is to amplify, through EDFA, the coded light pulses that afterpulse power is inconsistent in described application system；
Fig. 4 is the Gray code light pulse auto-correlation summation in described application system after EDFA；
The original transfer function used when Fig. 5 is simulation in background technology；
Fig. 6 is to the transmission function after original transfer function is demodulated by Gray described in Fig. 5；
Fig. 7 is the flow chart of the embodiment of the present invention one；
Fig. 8 is the signal graph in the embodiment of the present invention one after optical pulse code and optical fiber impulse response convolution；
The original transfer function that Fig. 9 uses when being and use the simulation of the embodiment of the present invention one method；
Figure 10 is to the transmission function after original transfer function demodulation described in Fig. 9；
Figure 11 is the structural representation of the embodiment of the present invention two.
Detailed description of the invention
Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is carried out clear, complete
Describe, it is clear that described embodiment is only a part of embodiment of the present invention rather than whole embodiments wholely.Based on
Embodiment in the present invention, it is every other that those of ordinary skill in the art are obtained under not making creative work premise
Embodiment, broadly falls into the scope of protection of the invention.
Embodiment one
The present invention, for a kind of embodiment of the signal demodulating method of distributed fiber-optic sensor system, can be applicable to Fig. 2 institute
In the scene shown, step is as it is shown in fig. 7, comprises following steps:
Step 701: obtain the impulse response volume of an optical pulse code sequence and optical pulse code sequence and testing fiber
Signal after Ji；
Should be noted that described optical pulse code sequence, can be any one of any one coded system generation
Individual optical pulse code sequence.
Preferably, described optical pulse code sequence, for two the optical pulse code sequences using complementary Gray code to obtain
Any one in row.
Preferably, it is thus achieved that the method for optical pulse code sequence, for the method generally used in prior art, particularly as follows: one
The laser that laser instrument sends, by the electrooptic modulator controlled by AWG (Arbitrary Waveform Generator), forms the pulse after coding.After coding
Pulse through erbium-doped fiber amplifier amplify after be received by photodetector, photodetector will coding after pulse
Becoming the signal of telecommunication, the signal of telecommunication passes to show in oscillograph, then is obtained optical pulse code sequence by computer.
Preferably, it is thus achieved that the method for the signal after the impulse response convolution of optical pulse code sequence and testing fiber, is existing
There is the method generally used in technology, particularly as follows: the optical pulse code sequence after erbium-doped fiber amplifier amplifies, Jing Guohuan
Row device enters in testing fiber, and the signal after the impulse response convolution of optical pulse code sequence and testing fiber is by photodetector
Being received, the signal after described convolution is become the signal of telecommunication by photodetector, and the signal of telecommunication passes to show in oscillograph
Show, then obtained the signal after convolution by computer, as shown in Figure 8.
Step 702: by the signal after the optical pulse code sequence of described acquisition and described convolution, by Fourier transform extremely
Frequency domain, is calculated the impulse response of testing fiber under frequency domain；
Described being calculated the impulse response of testing fiber under frequency domain, computing formula is:Wherein, H represents
The impulse response of testing fiber under frequency domain, Y represent by the optical pulse code sequence after Fourier transform to frequency domain with treat light-metering
The fine signal after impulse response convolution, AfRepresent by the optical pulse code sequence after Fourier transform to frequency domain.
Should be noted that described Fourier transform process completes in a computer.Fourier transform is ability
General knowledge known to field technique personnel, therefore detailed.
Step 703: by inverse fourier transform by described under frequency domain the impulse response of testing fiber be converted into time domain,
Impulse response to testing fiber.
Described by inverse fourier transform by described under frequency domain the impulse response of testing fiber be converted into time domain, calculate public affairs
Formula is:Wherein, h represents the impulse response of testing fiber under time domain, and Y represents by Fourier transform to frequency
Signal after the impulse response convolution of the optical pulse code sequence behind territory and testing fiber, AfRepresent by Fourier transform to frequency
Optical pulse code sequence behind territory.
Should be noted that described inverse fourier transform process completes in a computer.Inverse fourier transform is
Well known to a person skilled in the art general knowledge, therefore detailed.
It is simulated for Fig. 9 with the transmission function of 20km optical fiber, uses the present embodiment method to carry out what signal demodulation obtained
Transmission function is as shown in Figure 10, it can be seen that error is the least.
Use above-described embodiment, following beneficial effect can be reached: coded format is not required, can be used for various coding
Demodulation, only need to determine a coded sequence；In the condition that optical pulse code sequence is amplified through EDFA Erbium-Doped Fiber Amplifier
Under, the present embodiment uses pulsatile once input, no at all considers that complementary Gray code auto-correlation sum is that optical fiber impulse rings
Answer this condition, therefore reduce demodulating error.
Embodiment two
The present invention is for a kind of embodiment of the signal demodulating equipment of distributed fiber-optic sensor system, as shown in figure 11, and bag
Include,
Signal acquisition module 111, it is thus achieved that an optical pulse code sequence and described optical pulse code sequence and testing fiber
Impulse response convolution after signal；
Should be noted that described optical pulse code sequence, can be any one of any one coded system generation
Individual optical pulse code sequence.
Preferably, described optical pulse code sequence, for two the optical pulse code sequences using complementary Gray code to obtain
Any one in row.
Preferably, it is thus achieved that the method for optical pulse code sequence, for the method generally used in prior art, particularly as follows: one
The laser that laser instrument sends, by the electrooptic modulator controlled by AWG (Arbitrary Waveform Generator), forms the pulse after coding.After coding
Pulse through erbium-doped fiber amplifier amplify after, computer obtain.
Preferably, it is thus achieved that the method for the signal after the impulse response convolution of optical pulse code sequence and testing fiber, is existing
There is the method generally used in technology, particularly as follows: the optical pulse code sequence after erbium-doped fiber amplifier amplifies, Jing Guohuan
Row device enters in testing fiber, and the signal after the impulse response convolution of optical pulse code sequence and testing fiber is by photodetector
Being received, the signal after described convolution is become the signal of telecommunication by photodetector, and the signal of telecommunication passes to show in oscillograph
Show, then obtained the signal after convolution by computer.
Signal conversion module 112, by the signal after the optical pulse code sequence of described acquisition and described convolution, passes through Fourier
Leaf transformation, to frequency domain, is calculated the impulse response of testing fiber under frequency domain；
Described being calculated the impulse response of testing fiber under frequency domain, computing formula is:Wherein, H represents
The impulse response of testing fiber under frequency domain, Y represent by the optical pulse code sequence after Fourier transform to frequency domain with treat light-metering
The fine signal after impulse response convolution, AfRepresent by the optical pulse code sequence after Fourier transform to frequency domain.
Should be noted that described Fourier transform process completes in a computer.Fourier transform is ability
General knowledge known to field technique personnel, therefore detailed.
Signal inverse transform module 113, by inverse fourier transform by the described impulse response change of testing fiber under frequency domain
Shift to time domain, obtain the impulse response of testing fiber.
Described by inverse fourier transform by described under frequency domain the impulse response of testing fiber be converted into time domain, calculate public affairs
Formula is:Wherein, h represents the impulse response of testing fiber under time domain, and Y represents by Fourier transform to frequency
Signal after the impulse response convolution of the optical pulse code sequence behind territory and testing fiber, AfRepresent by Fourier transform to frequency
Optical pulse code sequence behind territory.
Should be noted that described inverse fourier transform process completes in a computer.Inverse fourier transform is
Well known to a person skilled in the art general knowledge, therefore detailed.
It should be noted that in this article, the relational terms of such as first and second or the like is used merely to a reality
Body or operation separate with another entity or operating space, and deposit between not necessarily requiring or imply these entities or operating
Relation or order in any this reality.And, term " includes ", " comprising " or its any other variant are intended to
Comprising of nonexcludability, so that include that the process of a series of key element, method, article or equipment not only include that those are wanted
Element, but also include other key elements being not expressly set out, or also include for this process, method, article or equipment
Intrinsic key element.In the case of there is no more restriction, statement " including ... " key element limited, it is not excluded that
Including process, method, article or the equipment of described key element there is also other identical element.
Each embodiment in this specification all uses relevant mode to describe, identical similar portion between each embodiment
Dividing and see mutually, what each embodiment stressed is the difference with other embodiments.Real especially for system
For executing example, owing to it is substantially similar to embodiment of the method, so describe is fairly simple, relevant part sees embodiment of the method
Part illustrate.
The foregoing is only presently preferred embodiments of the present invention, be not intended to limit protection scope of the present invention.All
Any modification, equivalent substitution and improvement etc. made within the spirit and principles in the present invention, are all contained in protection scope of the present invention
In.
Claims (10)
1. the signal demodulating method for distributed fiber-optic sensor system, it is characterised in that comprise the following steps:
Obtain the signal after the impulse response convolution of an optical pulse code sequence and optical pulse code sequence and testing fiber；
By the signal after the optical pulse code sequence obtained and convolution, respectively by Fourier transform to frequency domain, after conversion
Optical pulse code sequence and convolution after signal, be calculated the impulse response of testing fiber under frequency domain；
By inverse fourier transform, the impulse response of testing fiber under frequency domain obtained is converted into time domain, obtains testing fiber
Impulse response.
Signal demodulating method for distributed fiber-optic sensor system the most according to claim 1, it is characterised in that described
Be calculated the impulse response of testing fiber under frequency domain, computing formula is:Wherein, H represents and treats under frequency domain
The impulse response that light-metering is fine, Y represents the impulse by the optical pulse code sequence after Fourier transform to frequency domain Yu testing fiber
Signal after response convolution, AfRepresent by the optical pulse code sequence after Fourier transform to frequency domain.
Signal demodulating method for distributed fiber-optic sensor system the most according to claim 2, it is characterised in that described
By inverse fourier transform, the impulse response of testing fiber under frequency domain obtained is converted into time domain, computing formula is:Wherein, h represents the impulse response of testing fiber under time domain, after Y represents by Fourier transform to frequency domain
Signal after the impulse response convolution of optical pulse code sequence and testing fiber, AfAfter representing by Fourier transform to frequency domain
Optical pulse code sequence.
4., according to the signal demodulating method for distributed fiber-optic sensor system described in claim 1-3 any one, it is special
Levying and be, the optical pulse code sequence of described testing fiber is: original optical pulse coded sequence passes through EDFA Erbium-Doped Fiber Amplifier
It is amplified the optical pulse code sequence after processing.
Signal demodulating method for distributed fiber-optic sensor system the most according to claim 4, it is characterised in that described
Original optical pulse coded sequence be: any one in two the optical pulse code sequences using complementary Gray code to obtain.
6. the signal demodulating equipment for distributed fiber-optic sensor system, it is characterised in that include,
Signal acquisition module, it is thus achieved that an optical pulse code sequence and optical pulse code sequence and the impulse response of testing fiber
Signal after convolution；
Signal conversion module, by the signal after the optical pulse code sequence obtained and convolution, respectively by Fourier transform to frequency
Territory, according to the optical pulse code sequence after conversion and the signal after convolution, the impulse being calculated testing fiber under frequency domain rings
Should；
Signal inverse transform module, by inverse fourier transform by obtain when under frequency domain, the impulse response of testing fiber is converted into
Territory, obtains the impulse response of testing fiber.
Signal demodulating equipment for distributed fiber-optic sensor system the most according to claim 6, it is characterised in that described
Be calculated the impulse response of testing fiber under frequency domain, computing formula is:Wherein, H represents and treats under frequency domain
The impulse response that light-metering is fine, Y represents the impulse by the optical pulse code sequence after Fourier transform to frequency domain Yu testing fiber
Signal after response convolution, AfRepresent by the optical pulse code sequence after Fourier transform to frequency domain.
Signal demodulating equipment for distributed fiber-optic sensor system the most according to claim 7, it is characterised in that described
By inverse fourier transform, the impulse response of testing fiber under frequency domain obtained is converted into time domain, computing formula is:Wherein, h represents the impulse response of testing fiber under time domain, after Y represents by Fourier transform to frequency domain
Signal after the impulse response convolution of optical pulse code sequence and testing fiber, AfAfter representing by Fourier transform to frequency domain
Optical pulse code sequence.
9., according to the signal demodulating equipment for distributed fiber-optic sensor system described in claim 6-8 any one, it is special
Levying and be, the optical pulse code sequence of described testing fiber is: amplified by erbium-doped fiber by original optical pulse coded sequence
Device is amplified the optical pulse code sequence after processing.
Signal demodulating equipment for distributed fiber-optic sensor system the most according to claim 9, it is characterised in that institute
The original optical pulse coded sequence stated is: use in two optical pulse code sequences that complementary Gray code obtains is any one
Individual.
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