CN107782346B - Large-scale optical fiber grating sensing network demodulation system and method based on Gray code - Google Patents
Large-scale optical fiber grating sensing network demodulation system and method based on Gray code Download PDFInfo
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Abstract
The large-scale optical fiber grating sensing network demodulation system based on Gray code that the invention discloses a kind of, the control signal input of the signal output end connection adjustable narrow-band light source of module occurs for the Gray code pulse, the first interface of the signal output end connection photo-coupler of adjustable narrow-band light source, the second interface of photo-coupler accesses grating sensing network, the third interface of photo-coupler passes through the signal input part of photoelectric converter connection signal acquisition module, the signal input part of the signal output end connection signal processing module of signal acquisition module；The present invention will quote gray encoding principle, and optical fiber grating sensing network feature is combined to propose for pulse code and decoding process specific to optical fiber grating sensing network.
Description
Technical field
The invention belongs to fiber grating sensing technology fields, and in particular to a kind of large-scale optical fiber grating based on Gray code
Sensing network demodulation system and method.
Technical background
With the continuous maturation of fiber grating sensing technology, fiber grating is widely used in large-scale soil with its unique advantage
The forecast and monitoring of the safe and healthy monitoring and disaster such as wood engineering, power engineering, petrochemical industry project, bridge, tunnel, dam, mining industry.
Since engineering application requirement is continuously increased, optical fiber grating sensing network is just extensive towards long range, large capacity, quasi-distributed etc.
Networking mode development.
For large-scale network-estabilishing mode, the mode that multiple repairing weld is averaged is generallyd use to carry out noise reduction to signal at present,
But for large-scale optical fiber grating sensing network, completing one group of data sampling, time-consuming, and engineer application is to sensing network
Detection speed require, improve signal-to-noise ratio according to average mode is largely taken, then can reduce the detection speed of system, thus
Be not suitable for largely sampling the mode being averaged and carrying out noise reduction in the engineer application of short time real-time monitoring, it is certain in order to reach
Demodulation accuracy and demodulation speed, demodulating system in engineer application are generally averaged using less time.
On a large scale entirely in optical fiber grating sensing network, there is presently no introducing coding techniques to do modulation and demodulation,
And in long-distance optical fiber sensing network, the utilization of coding techniques is more mature at present, such as Gray code, S code, CCPON sequence
And hybrid coding etc. has been well used in the demodulation of fibre scattering effect between various patterns.It is external such as 1989
Scholar Moshe Nazarathy, S.A.Newton et al. are in " Real-Time Long Rang Complement
Correlation Optical Time Domain Reflectometer " in by gray encoding technology introduce OTDR system,
Dynamic Range is improved using Gray code complementary characteristic and to signal de-noising；Liang Hao " is detected in paper based on sequential coding
The research of the Brillouin light fiber sensor of pulse " in reference Gray code improve system signal noise ratio；Liu Jingjun et al. " is being based on C_
The OTDR system signal noise ratio improvement method of S compound key " C-S compound key coding mode is proposed to improve system signal noise ratio.For big
Scale entirely with array grating for, since optical grating reflection optical wavelength is identical in grating array, if in optical fiber grating sensing network
The pulse code and decoding process of Gray code are directly quoted, then in the light pulse generated by continuous programming code mode, there are pulses
Width crosses the indistinguishable light pulse of ambassador's adjacent gratings reflected light, so that adjacent gratings reflected light can be under a wide light pulse
Overlapping crosstalk phenomenon is generated, and then can not correctly be demodulated.
Summary of the invention
The purpose of the present invention is in view of the above technical problems, provide a kind of large-scale optical fiber grating sensing based on Gray code
Network demodulation system and method.It introduces entirely in order to avoid the generation of above-mentioned crosstalk phenomenon and by coding techniques with grating array demodulation
In, the present invention will quote gray encoding principle, and optical fiber grating sensing network feature is combined to propose to be directed to optical fiber grating sensing
Pulse code and decoding process specific to network.
In order to achieve this, the large-scale optical fiber grating sensing network demodulation system designed by the present invention based on Gray code
System, which is characterized in that it includes that module, light path module, signal processing module occur for Gray code pulse, and the light path module includes
Adjustable narrow-band light source, photo-coupler, grating sensing network, photoelectric converter and signal acquisition module, the Gray code pulse hair
The control signal input of the signal output end connection adjustable narrow-band light source of raw module, the signal output end of adjustable narrow-band light source connect
The first interface of photo-coupler is connect, the second interface of photo-coupler accesses grating sensing network, and the third interface of photo-coupler connects
Connect photoelectric converter input terminal, the signal input part of photoelectric converter output end connection signal acquisition module, signal acquisition module
Signal output end connection signal processing module signal input part；
The Gray code pulse occurs module and is used to generate original gray code sequence complementation sequence according to Gray code production principle
Arrange A and B；
The Gray code pulse occurs module and is used to generate the first Gray according to original gray code sequence complementary series A and B
Code offset sequence is to A1And A2And second Gray code offset sequence to B1And B2, the A1=(1+A)/2, A2=(1-A)/2,
B1=(1+B)/2, B2=(1-B)/2；
The Gray code pulse occurs module and is used for the first Gray code offset sequence to A1And A2It is biased with the second Gray code
Sequence is to B1And B2It is biased sequence extension zero padding operation respectively；
Module occurs for the Gray code pulse for implementation sequence to A1And A2、B1And B2In 1 and 0 indicate high level with
Low level width, if the grating space of optical fiber optical grating array is L, the width W of design driven signal low and high level is W=
NL/c, n is optical fibre refractivity in formula, and c is the light velocity；
The Gray code pulse occurs module and is also used to extending offset sequence into the first Gray code biasing after zero padding operation
Sequence is to A'1And A'2And the second Gray code offset sequence after offset sequence extension zero padding operation is to B'1And B'2It generates and corresponds to
Four groups of light pulse driving signals.
A kind of large-scale optical fiber grating sensing network demodulation method based on Gray code, which is characterized in that it includes as follows
Step:
Step 1: the Gray code pulse occurs module and generates original gray code sequence complementation according to Gray code production principle
Sequence A and B；Gray code pulse occurs module and generates the first Gray code biasing sequence according to original gray code sequence complementary series A and B
Column are to A1And A2And second Gray code offset sequence to B1And B2, the A1=(1+A)/2, A2=(1-A)/2, B1=(1+
B)/2、B2=(1-B)/2；The first Gray code of module design offset sequence occurs for Gray code pulse to A1And A2And second Gray
Code offset sequence is to B1And B2The width of represented low and high level；Module occurs for Gray code pulse to the first Gray code offset sequence
To A1And A2With the second Gray code offset sequence to B1And B2It is biased sequence extension zero padding operation respectively；Gray code pulse hair
Raw module is by the first Gray code offset sequence after offset sequence extension zero padding operation to A'1And A'2And second Gray code biasing
Sequence is to B'1And B'2Generate corresponding four groups of light pulse driving signals；
Step 2: four groups of light pulse driving signals are successively sent to adjustable narrow by the Gray code pulse generation module
Band light source, adjustable narrow-band light source are λ for above-mentioned four groups of light pulse driving signals based on the received and the corresponding central wavelength of generationi
Train pulse light PA'1、PA'2、PB'1、PB'2；
Step 3: central wavelength λiTrain pulse light PA'1、PA'2、PB'1、PB'2Enter grating by photo-coupler to pass
Feel network, reflected light is obtained in grating sensing network, signal acquisition module collects above-mentioned reflected light by photoelectric converter
Obtain corresponding central wavelength lambdaiThe time domain electric signal of lower grating array
Step 4: the signal processing module is according to central wavelength lambdaiThe time domain electric signal of lower grating arrayIt is demodulated to obtain central wavelength lambdaiThe time domain response result y of lower grating array.
The central wavelength lambdaiThe time domain response result y of lower grating array is calculated by following equation；
In formula, * indicates auto-correlation computation,Indicate that convolution algorithm, h indicate that grating array receptance function, l indicate original lattice
The length of thunder code complement thereof A or B, A ', B ' are the zero padding sequence spreading of original gray code sequence complementary series, original lattice
The zero padding sequence spreading A ' of thunder code complement thereof, the sequence extension digit M of B ' are extended by optical pulse width W, pulse signal
The sample rate S three parts decision of digit N, data sampling module, i.e.,
M=W × S × (N+1) -1
The zero padding sequence spreading A ' of the original gray code sequence complementary series is in original gray code sequence complementary series A
In each adjacent code between supplement the position M 0；The zero padding sequence spreading B ' of the original gray code sequence complementary series is original
The position M 0 is supplemented between each adjacent code in gray code sequence complementary series B.
The invention has the benefit that
The demodulation method traditional compared to large-scale optical fiber grating sensing network, it is real that the present invention is based on gray encoding modes
Existing optical fiber optical grating sensing network demodulation can effectively solve coding techniques and introduce the superposition string that grating array clock pulse breaks through wide generation
The phenomenon different from the inconsistent generation response intensity of optical pulse width is disturbed, equivalent can be completed by four groups of sampled signals under this methodology
A large amount of samplings take average method, thus can solve largely to sample the limitation that time-consuming to demodulation speed in OTDR demodulation, can pass through
Less sampling effectively improves the signal-to-noise ratio and dynamic range of sensing network, and then increases the distance of optical fiber grating sensing network.
Detailed description of the invention
Fig. 1 is system construction drawing of the invention；
Fig. 2 is gray encoding pulse schematic diagram after extension zero padding；
Fig. 3 is the grating spectrum figure demodulated under the different pulse spacings；
Fig. 4 is the method for the present invention and multiple repairing weld method in 10km optical fiber grating sensing end result in time domain comparison diagram；
In figure, module, 2-light path modules, 2.1-adjustable narrow-band light sources, 2.2-optical couplings occur for 1-Gray code pulse
Device, 2.3-grating sensing networks, 2.4-photoelectric converters, 2.5-signal acquisition modules, 3-signal processing modules.
Specific embodiment
Below in conjunction with drawings and examples, the present invention is described in further detail:
Large-scale optical fiber grating sensing network demodulation system based on Gray code of the invention, as shown in Figure 1, it includes lattice
Thunder code pulse generating module 1, light path module 2, signal processing module 3, the light path module 2 include adjustable narrow-band light source 2.1, light
Mould occurs for coupler 2.2, grating sensing network 2.3, photoelectric converter 2.4 and signal acquisition module 2.5, the Gray code pulse
The control signal input of the signal output end connection adjustable narrow-band light source 2.1 of block 1, the signal output of adjustable narrow-band light source 2.1
The first interface of end connection photo-coupler 2.2, the second interface of photo-coupler 2.2 access grating sensing network 2.3, photo-coupler
2.2 third interface connects 2.4 input terminal of photoelectric converter, 2.4 output end connection signal acquisition module 2.5 of photoelectric converter
Signal input part, the signal input part of the signal output end connection signal processing module 3 of signal acquisition module 2.5；
In above-mentioned technical proposal, it is original for generating according to Gray code production principle that module 1 occurs for the Gray code pulse
Gray code sequence complementary series A and B；
Above-mentioned original gray code sequence complementary series A and B can be with are as follows:
A[1 1 1 -1 1 1 -1 1 1 1 1 ... -1 1 1 1 -1 1 1 ... -1 -1 1 1 1 -1
1...]
B[1 1 1 -1 1 1 -1 1 1 1 1 ... -1 -1 -1 -1 1 -1 -1 ... 1 1 -1 -1 -1 1
-1...]
In above-mentioned technical proposal, there can only be the light pulse of unipolarity forward direction in light path system, A, B need to be biased,
The Gray code pulse occurs module 1 and is used to generate the first Gray code biasing sequence according to original gray code sequence complementary series A and B
Column are to A1And A2And second Gray code offset sequence to B1And B2, the A1=(1+A)/2, A2=(1-A)/2, B1=(1+
B)/2、B2=(1-B)/2；
There can only be the light pulse of unipolarity forward direction in light path system, A, B need to be biased,
In above-mentioned technical proposal, the Gray code pulse occurs module 1 and is used for the first Gray code offset sequence to A1And A2
With the second Gray code offset sequence to B1And B2It is biased sequence extension zero padding operation respectively；
Module occurs for the Gray code pulse for implementation sequence to A1And A2、B1And B2In 1 and 0 indicate high level with
Low level width, if the grating space of optical fiber optical grating array is L, the width W for designing light pulse is
N is optical fibre refractivity in formula, and c is the light velocity；
If existing in light pulse sequence continuous according to sequence and pulse width generation light pulse after the biasing of original pattern
The width for grating space of the 1 wide light pulse indicated, this width light pulse is excessive, i.e. two neighboring light is passed through in light pulse
After grid, the reflected light of two neighboring grating can generate overlapping crosstalk, and continuous 1 number is different in original series indicates light pulse
Width is also different, then the intensity for the reflection light pulse that one group of sequence light pulse obtains at the same grating is not also identical, this will
Grating can not correctly be demodulated.It, need to be according to the above scheme to offset sequence A in order to avoid the generation of above-mentioned two situations1、A2、B1、B2
Extend zero padding.Make to become independent 1 after continuous 1 extension zero padding in sequence, i.e., each 1 one light pulse of independent expression and light pulse
Between spacing increase, two reflected lights are not overlapped crosstalk when such a light pulse acts on two gratings, can also make each arteries and veins
It is consistent to rush obtained response intensity.
In above-mentioned technical proposal, the Gray code pulse occurs that module 1 is also used to will be after offset sequence extension zero padding operation
The first Gray code offset sequence to A'1And A'2And the second Gray code offset sequence pair after offset sequence extension zero padding operation
B'1And B'2Generate corresponding four groups of light pulse driving signals.A'1、A'2、B'1、B'2Each bit sign represents one in sequence
Light pulse (pulse width W), 1 indicates to generate pulse, and 0 indicates not generate pulse.
In above-mentioned technical proposal, the Gray code pulse occurs module 1 and successively sends out four groups of light pulse driving signals
Adjustable narrow-band light source 2.1 is given, adjustable narrow-band light source 2.1 is used for above-mentioned four groups of light pulse driving signals and generation based on the received
Corresponding central wavelength is λiTrain pulse light PA'1、PA'2、PB'1、PB'2。
In above-mentioned technical proposal, the central wavelength is λiTrain pulse light PA'1、PA'2、PB'1、PB'2By optocoupler
Clutch 2.2 enters grating sensing network 2.3, reflected light is obtained in grating sensing network 2.3, reflected light is again by coupler
2.2 couplings reach photoelectric converter 2.4, are converted to electric signal in photoelectric converter 2.4, signal acquisition module 2.5 acquires telecommunications
Number obtaining above-mentioned reflected light obtains corresponding central wavelength lambdaiThe time domain electric signal of lower grating array
In above-mentioned technical proposal, the signal processing module 3 is according to central wavelength lambdaiThe time domain electric signal of lower grating arrayIt is demodulated to obtain central wavelength lambdaiThe time domain response result y of lower grating array.
In above-mentioned technical proposal, it is described to the first Gray code offset sequence to A1And A2With the second Gray code offset sequence pair
B1And B2It is each in original gray code sequence complementary series A for being biased the specific method of sequence extension zero padding operation respectively
Supplement the position N 0 between a adjacent code, 3≤N≤6, supplement N between each adjacent code in original gray code sequence complementary series B
0,3≤N≤6.Extension zero padding mode does not change Gray code complementary characteristic.
Extension mends 3 zero between each sequence in experiment, i.e., are as follows:
A:[1 000 1 000 1 000 -1 000 1 000 1 000 -1 000 1 000]
B:[1 000 1 000 1 000 -1 000 -1 000 -1 000 1 000 -1 000]
As shown in Fig. 2, each in sequence 1 or -1 represents a drive pulse signal, but due in photosystem only
Unidirectional positive polarity code can be used to indicate a light pulse, thus A, B need to be biased, after figure a is the biasing of continuous type A code
A1、A2A in code1The corresponding continuous type coded pulse driving signal schematic diagram of code ([111 01101]), figure b are the A after zero padding1
The corresponding coded pulse signal signal of code ([1 000 1 000 1 000 0 000 1 000 1 000 0 000 1 000])
Figure, therein 1, which represents pulsed drive module, generates pulse signal, and 0 indicates not generate pulse signal.
For extending the value of number N of zero padding in experiment obtained by experimental verification, experimental result as shown in figure 3,
It is the spectrogram of neighbouring 4 gratings of 5km in 10km optical fiber grating sensing network when extension zero takes different value: figure a, b, c, d, e
The spectrogram of respectively N above-mentioned 4 gratings when taking 0,1,2,3,4, figure f are above-mentioned 4 gratings under non-coded manner pulse
Spectrogram.By can be obtained to comparison shape and Wavelength demodulation result: can correctly demodulate spectral information when N >=3, and N takes herein
Value will participate in the calculating of sequence extension zero padding digit in subsequent demodulating algorithm.
In above-mentioned technical proposal, the central wavelength lambdaiThe time domain response result y of lower grating array is calculated by following equation
It obtains；
In formula, * indicates auto-correlation computation,Indicate that convolution algorithm, h indicate that grating array receptance function, l indicate original lattice
The length of thunder code complement thereof A or B, A ', B ' are the zero padding sequence spreading of original gray code sequence complementary series, original lattice
The zero padding sequence spreading A ' of thunder code complement thereof, the sequence extension digit M of B ' are extended by optical pulse width W, pulse signal
The sample rate S three parts decision of digit N, data sampling module, i.e.,
M=W × S × (N+1) -1
The zero padding sequence spreading A ' of the original gray code sequence complementary series is in original gray code sequence complementary series A
In each adjacent code between supplement the position M 0；The zero padding sequence spreading B ' of the original gray code sequence complementary series is original
The position M 0 is supplemented between each adjacent code in gray code sequence complementary series B.
As optical pulse width degree W is 16ns, light pulse sequence extension digit N is 3, the sample rate S of sampling system is
250MHz, then the zero padding digit M of A/B code are as follows:
M=W × S × (N+1) -1
=16 × 250 × 10^6/10^9 × (3+1) -1
=15
16 × 250 × 10^6/10^9 indicates the points that single pulse obtains under 250MHz sample rate in formula；3+1 is indicated
How many equivalent pulse width of width between two adjacent encoder pulse center intervals.Last calculated result 15 then indicates
15 0 need to be extended between [1 11010 1...1,101001 0...] original series each element when demodulating
(the digit M of the extension can also be obtained by adjacent pulse interval points observation in time-domain sampling signal, and be obtained with above-mentioned theory
Result fit like a glove), the sequence after extension carries out related calculation with sampled signal again, so far completes central wavelength lambdaiLower optical fiber light
The demodulation of grid sensing network；
A kind of large-scale optical fiber grating sensing network demodulation method based on Gray code, it includes the following steps:
Step 1: the Gray code pulse occurs module 1 and generates original gray code sequence complementation according to Gray code production principle
Sequence A and B；Gray code pulse occurs module 1 and generates the biasing of the first Gray code according to original gray code sequence complementary series A and B
Sequence is to A1And A2And second Gray code offset sequence to B1And B2, the A1=(1+A)/2, A2=(1-A)/2, B1=(1+
B)/2、B2=(1-B)/2；Gray code pulse occurs module 1 and designs the first Gray code offset sequence to A1And A2And second lattice
Thunder code offset sequence is to B1And B2The width of represented low and high level；Gray code pulse occurs module 1 and biases sequence to the first Gray code
Column are to A1And A2With the second Gray code offset sequence to B1And B2It is biased sequence extension zero padding operation respectively；Gray code pulse
Module 1 occurs by the first Gray code offset sequence after offset sequence extension zero padding operation to A'1And A'2And second Gray code
Offset sequence is to B'1And B'2Generate corresponding four groups of light pulse driving signals；
Step 2: four groups of light pulse driving signals are successively sent to adjustable narrow by the Gray code pulse generation module 1
Band light source 2.1, adjustable narrow-band light source 2.1 is for above-mentioned four groups of light pulse driving signals based on the received and generates cardiac wave in corresponding
A length of λiTrain pulse light PA'1、PA'2、PB'1、PB'2；
Step 3: central wavelength λiTrain pulse light PA'1、PA'2、PB'1、PB'2Enter light by photo-coupler 2.2
Grid sensing network 2.3, obtains reflected light in grating sensing network 2.3, and reflected light couples again by coupler 2.2 and reaches light
Electric transducer 2.4 is converted to electric signal in photoelectric converter 2.4, and signal acquisition module 2.5 acquires electric signal and obtains above-mentioned reflection
Light obtains corresponding central wavelength lambdaiThe time domain electric signal of lower grating array
Step 4: the signal processing module 3 is according to central wavelength lambdaiThe time domain electric signal of lower grating arrayIt is demodulated to obtain central wavelength lambdaiThe time domain response result y of lower grating array.
Present invention combination optical fiber grating sensing network feature propose peculiar light pulse gray encoding mode with it is corresponding mutual
Related operation algorithm, can be a large amount of average in four samplings of two groups of coded sequences and completion equivalent under computing cross-correlation algorithm,
The dynamic range of demodulation accuracy and system can be effectively improved while guaranteeing demodulation speed, while can also expand fiber grating survey
It measures sensing network and measures distance.
The content that this specification is not described in detail belongs to the prior art well known to professional and technical personnel in the field.
Claims (8)
1. a kind of large-scale optical fiber grating sensing network demodulation system based on Gray code, which is characterized in that it includes Gray code
Pulse generating module (1), light path module (2), signal processing module (3), the light path module (2) includes adjustable narrow-band light source
(2.1), photo-coupler (2.2), grating sensing network (2.3), photoelectric converter (2.4) and signal acquisition module (2.5), it is described
The control signal input of signal output end connection adjustable narrow-band light source (2.1) of module (1) occurs for Gray code pulse, adjustable narrow
The first interface of signal output end connection photo-coupler (2.2) with light source (2.1), the second interface of photo-coupler (2.2) connect
Enter grating sensing network (2.3), the third interface of photo-coupler (2.2) connects photoelectric converter (2.4) input terminal, photoelectric conversion
The signal input part of device (2.4) output end connection signal acquisition module (2.5), the signal output end of signal acquisition module (2.5)
The signal input part of connection signal processing module (3)；
The Gray code pulse occurs module (1) and is used to generate original gray code sequence complementary series according to Gray code production principle
A and B；
The Gray code pulse occurs module (1) and is used to generate the first Gray code according to original gray code sequence complementary series A and B
Offset sequence is to A1And A2And second Gray code offset sequence to B1And B2, the A1=(1+A)/2, A2=(1-A)/2, B1
=(1+B)/2, B2=(1-B)/2；
The Gray code pulse occurs module (1) and is used for the first Gray code offset sequence to A1And A2It is biased with the second Gray code
Sequence is to B1And B2It is biased sequence extension zero padding operation respectively；
The Gray code pulse occurs the first Gray code that module (1) is also used to extend offset sequence after zero padding operation and biases sequence
Column are to A1' and A'2And the second Gray code offset sequence after offset sequence extension zero padding operation is to B1' and B'2It generates corresponding
Four groups of light pulse driving signals.
2. the large-scale optical fiber grating sensing network demodulation system according to claim 1 based on Gray code, feature exist
In: module (1) occurs for the Gray code pulse for designing the first Gray code offset sequence to A1And A2, the second Gray code biasing
Sequence is to B1And B2In 1 and 0 indicate high level and low level width, if the fiber grating battle array in grating sensing network (2.3)
The grating space of column is L, then the width W for designing light pulse driving signal low and high level is W=nL/c, and n is optical fiber refraction in formula
Rate, c are the light velocity；
The Gray code pulse occurs module (1) and four groups of light pulse driving signals is successively sent to adjustable narrow-band light source
(2.1), adjustable narrow-band light source (2.1) for above-mentioned four groups of light pulse driving signals based on the received and generates corresponding central wavelength
For λiTrain pulse light PA '1、PA'2、PB’1、PB'2。
3. the large-scale optical fiber grating sensing network demodulation system according to claim 2 based on Gray code, feature exist
In: the central wavelength is λiTrain pulse light PA '1、PA'2、PB’1、PB'2Enter grating sensing by photo-coupler (2.2)
Network (2.3), obtains reflected light in grating sensing network (2.3), and reflected light couples again by coupler (2.2) and reaches light
Electric transducer (2.4) is converted to electric signal in photoelectric converter (2.4), and signal acquisition module (2.5) acquisition electric signal obtains
It states reflected light and obtains corresponding central wavelength lambdaiThe time domain electric signal of lower grating array
4. the large-scale optical fiber grating sensing network demodulation system according to claim 3 based on Gray code, feature exist
In: the signal processing module (3) is according to central wavelength lambdaiThe time domain electric signal of lower grating array
It is demodulated to obtain central wavelength lambdaiThe time domain response result y of lower grating array.
5. the large-scale optical fiber grating sensing network demodulation system according to claim 1 based on Gray code, feature exist
In: it is described to the first Gray code offset sequence to A1And A2With the second Gray code offset sequence to B1And B2It is biased sequence respectively
The specific method of column extension zero padding operation is that N are supplemented between each adjacent code in original gray code sequence complementary series A
0,3≤N≤6 supplement the position N 0,3≤N≤6 between each adjacent code in original gray code sequence complementary series B.
6. the large-scale optical fiber grating sensing network demodulation system according to claim 4 based on Gray code, feature exist
In: the central wavelength lambdaiThe time domain response result y of lower grating array is calculated by following equation；
In formula, * indicates auto-correlation computation,Indicate that convolution algorithm, h indicate that grating array receptance function, l indicate original Gray code
The length of complement thereof A or B, A ', B ' are the zero padding sequence spreading of original gray code sequence complementary series, original Gray code
The zero padding sequence spreading A ' of complement thereof, the sequence extension digit M of B ' extend digit by optical pulse width W, pulse signal
N, the sample rate S three parts of data sampling module determine, i.e.,
M=W × S × (N+1) -1
The zero padding sequence spreading A ' of the original gray code sequence complementary series is in original gray code sequence complementary series A
The position M 0 is supplemented between each adjacent code；The zero padding sequence spreading B ' of the original gray code sequence complementary series is in original Gray
The position M 0 is supplemented between each adjacent code in code complement thereof B.
7. a kind of large-scale optical fiber grating sensing network demodulation method based on Gray code, which is characterized in that it includes following step
It is rapid:
Step 1: Gray code pulse occurs module (1) and generates original gray code sequence complementary series A according to Gray code production principle
And B；Gray code pulse occurs module (1) and generates the first Gray code offset sequence according to original gray code sequence complementary series A and B
To A1And A2And second Gray code offset sequence to B1And B2, the A1=(1+A)/2, A2=(1-A)/2, B1=(1+B)/
2、B2=(1-B)/2；Gray code pulse occurs module (1) and designs the first Gray code offset sequence to A1And A2And second Gray
Code offset sequence is to B1And B2The width of represented low and high level；Gray code pulse occurs module (1) and biases sequence to the first Gray code
Column are to A1And A2With the second Gray code offset sequence to B1And B2It is biased sequence extension zero padding operation respectively；Gray code pulse
Module (1) occurs by the first Gray code offset sequence after offset sequence extension zero padding operation to A1' and A'2And second Gray
Code offset sequence is to B1' and B'2Generate corresponding four groups of light pulse driving signals；
Step 2: the Gray code pulse occurs module (1) and four groups of light pulse driving signals is successively sent to adjustable narrow-band
Light source (2.1), adjustable narrow-band light source (2.1) is for above-mentioned four groups of light pulse driving signals based on the received and generates corresponding center
Wavelength is λiTrain pulse light PA '1、PA'2、PB’1、PB'2；
Step 3: central wavelength λiTrain pulse light PA '1、PA'2、PB’1、PB'2Enter grating by photo-coupler (2.2)
Sensing network (2.3), obtains reflected light in grating sensing network (2.3), and reflected light is coupled to again by coupler (2.2)
Up to photoelectric converter (2.4), electric signal is converted in photoelectric converter (2.4), signal acquisition module (2.5) acquisition electric signal obtains
To corresponding central wavelength lambdaiThe time domain electric signal of lower grating array
Step 4: signal processing module (3) is according to central wavelength lambdaiThe time domain electric signal of lower grating arrayIt is demodulated to obtain central wavelength lambdaiThe time domain response result y of lower grating array.
8. the large-scale optical fiber grating sensing network demodulation method according to claim 7 based on Gray code, feature exist
In: the central wavelength lambdaiThe time domain response result y of lower grating array is calculated by following equation；
In formula, * indicates auto-correlation computation,Indicate that convolution algorithm, h indicate that grating array receptance function, l indicate original Gray code
The length of complement thereof A or B, A ', B ' are the zero padding sequence spreading of original gray code sequence complementary series, original Gray code
The zero padding sequence spreading A ' of complement thereof, the sequence extension digit M of B ' extend digit by optical pulse width W, pulse signal
N, the sample rate S three parts of data sampling module determine, i.e.,
M=W × S × (N+1) -1
The zero padding sequence spreading A ' of the original gray code sequence complementary series is in original gray code sequence complementary series A
The position M 0 is supplemented between each adjacent code；The zero padding sequence spreading B ' of the original gray code sequence complementary series is in original Gray
The position M 0 is supplemented between each adjacent code in code complement thereof B.
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