CN107607766A - The truly random four states modulation-demo-demodulation method of optical fiber current mutual inductor specular - Google Patents
The truly random four states modulation-demo-demodulation method of optical fiber current mutual inductor specular Download PDFInfo
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- CN107607766A CN107607766A CN201710666589.2A CN201710666589A CN107607766A CN 107607766 A CN107607766 A CN 107607766A CN 201710666589 A CN201710666589 A CN 201710666589A CN 107607766 A CN107607766 A CN 107607766A
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Abstract
The invention discloses a kind of truly random four states modulation-demo-demodulation method of optical fiber current mutual inductor specular, this method comprises the following steps：Electric on optical fiber current mutual inductor, its A/D converter starts sampling and obtains hits；A/D converter will be transferred to data demodulation module in hits, lowest order AD [0] of the data demodulation module in hits produces random sequence and Stochastic Modulation number；Data demodulation module generates truly random four state of specular according to random sequence and Stochastic Modulation number and modulated.The advantages of present invention had both had binary states, four states and four state Stochastic Modulation demodulation methods concurrently, and can makes up the deficiency of binary states, four states and four state Stochastic Modulations, can reduce noise, reduction and stable output zero-bit, solve low current measuring accuracy and DC test stability.
Description
Technical field
The invention belongs to fibre-optic current mutual inductance field, more particularly to a kind of optical fiber current mutual inductor specular are truly random
Four state modulation-demo-demodulation methods.
Background technology
Optical fiber current mutual inductor has simple insulation, small volume, safe and reliable, numeral as New type of current measuring apparatus
Change, be intelligent and measure, measure, protect the advantages that integrated, being the critical equipment of intelligent substation construction, develop in recent years fast
Speed, technological progress is larger, in Intelligent transformer station small batch application, represents the developing direction of transformer industry, not
Traditional electromagnetic transformer will progressively be substituted as power measurement field mainstream configuration equipment by carrying out optical fiber current mutual inductor.
Optical fiber current mutual inductor is current optical current mutual inductor main flow engineer applied scheme, and it mainly has light path, circuit
And modulation-demo-demodulation method composition, wherein modulation-demo-demodulation method is an important factor for influenceing optical fiber current mutual inductor performance.Light at present
Modulation-demo-demodulation method used in fiber current mutual inductor is mainly adjusted using binary states square-wave frequency modulation, four state Staircase waves, four state pseudorandoms
Three kinds of modulator approaches are made, wherein binary states square-wave frequency modulation amplitude is ± pi/2, and modulation period is optical fiber current mutual inductor optical interference circuit sheet
Transition time τ is levied, modulation is alternately repeated progress, as shown in Figure 1.Four state Staircase wave amplitudes are ± pi/2, ± 3 pi/2s, are modulated
Cycle is τ/2 for the half of optical fiber current mutual inductor intrinsic transition time, and ± pi/2, the modulation of ± 3 pi/2s are also to be alternately repeated progress,
As shown in Figure 2.Four state pseudorandom ripple modulation amplitudes are ± pi/2, ± 3 pi/2s, are getted over for optical fiber current mutual inductor is intrinsic modulation period
The half of time is τ/2, and four modulation amplitudes occur at random according to the random sequence for determining length, as shown in Figure 3.Binary states square wave
It is that positive and negative modulation amplitude frequency of occurrence is equal with four state staircase waveform advantages, output zero-bit is small and stably, without carrying out zero compensation.
Shortcoming is rule modulation period, modulation mode determine it is constant, modulated signal easily produce disturb and act in detected signal,
Cause larger noise, poor linearity, be unfavorable for low current test, the dead band that can't detect can be produced.Four state pseudorandom modulations are excellent
Point is ± pi/2, ± 3 pi/2 modulated randoms occur, and modulation mode is random, detection signal will not be disturbed, noise is small, linear
Spend, without dead band.Shortcoming be ± pi/2, ± 3 pi/2 modulated random sequences be determined by a row, the random number of regular length is given birth to
Into, modulate according to regular length random number implementation, after the completion of modulation repeat progresss, therefore be referred to as the state of pseudorandom four adjust
System, its positive and negative modulation amplitude is unequal, and output zero-bit is larger, easy fluctuation, and electric current reversely after zero-bit there is asymmetry.
Binary states square wave, four state ladders, which involve the modulation of four state pseudorandom ripples, the advantages of intrinsic and shortcoming, caused by it by mistake
Poor factor certainly exists.Noise, which crosses conference, influences low current measuring accuracy and electric quantity metering application.Zero-bit size and stability meeting
Have a strong impact on direct current measuring accuracy.Therefore, optical fiber current mutual inductor can when carrying out low current test or direct current electrical testing
Take the necessary measures and above mentioned problem is suppressed or eliminated.Under normal circumstances, prior art means can be by the method for sowing
Solved：First, by optimizing current transformer optical interference circuit, noise level is reduced, improves measuring accuracy.Second, pass through increasing
Add the sensing ring coiling number of turns, improve sensitive signal to noise ratio to reduce noise.Third, built by exporting zero-bit to current transformer
Mould compensates, and eliminating zero-bit influences.Fourth, by improving and optimizating, modulation-demo-demodulation method carries out noise suppressed and zero-bit size controls.Just
State-of-the art, optimization light path are limited to domestic existing optic technology level, and noise reduction is limited.Increase sensing ring coiling circle
Number can greatly improve optical fiber current mutual inductor noise level, but multi-turn technique for coiling difficulty is larger, and yield rate is relatively low, and cost increases
Add, can not produce in batches.Due to optical fiber current mutual inductor zero-bit poor repeatability and fluctuation and asymmetry be present, zero-bit modeling is mended
It is unsatisfactory to repay result.It is to reduce noise that innovation is carried out to modulation-demo-demodulation method, the important method of stable zero-bit, but current effect
It is unsatisfactory.
The content of the invention
Present invention solves the technical problem that it is：Overcome the deficiencies in the prior art, there is provided a kind of optical fiber current mutual inductor is used
The truly random four states modulation-demo-demodulation method of specular, the advantages of both having had binary states, four states and four state Stochastic Modulation demodulation methods concurrently, again
The deficiency of binary states, four states and four state Stochastic Modulations is can overcome the disadvantages that, noise, reduction and stable output zero-bit can be reduced, solve small electricity
Current test precision and DC test stability.
The object of the invention is achieved by the following technical programs：A kind of optical fiber current mutual inductor specular is truly random
Four state modulation-demo-demodulation methods, this method comprise the following steps：
(1) electric on optical fiber current mutual inductor, its A/D converter starts sampling and obtains hits；
(2) A/D converter will be transferred to data demodulation module in hits in step (1), and data demodulation module is according to adopting
Lowest order AD [0] in sample number produces random sequence and Stochastic Modulation number；
(3) data demodulation module is truly random according to random sequence in step (2) and Stochastic Modulation number generation specular
Four states are modulated.
In the above-mentioned truly random four states modulation-demo-demodulation method of optical fiber current mutual inductor specular, also comprise the following steps：
(3-1) is by the modulation of specular truly random four state is by A/D converter and discharge circuit is after-applied arrives Y waveguide.
In the above-mentioned truly random four states modulation-demo-demodulation method of optical fiber current mutual inductor specular, in the step (3),
The truly random four states modulation of generation specular comprises the following steps：
(4) data demodulation module produces truly random four state according to random sequence and modulated, and data demodulation module is according to step (2)
In Stochastic Modulation number carry out application modulation, when application modulation number be more than step (2) in Stochastic Modulation number when, sentence
Whether truly random four states modulation meets specular caused by disconnected；
(5) when meeting specular, by the tune of the application for the Stochastic Modulation number being more than in step (4) in step (2)
Truly random four state modulation before number processed carries out mirror image and implements to form the truly random four states modulation of specular；
(6) when being unsatisfactory for specular, modulation is continued to until meeting specular condition, repeat step (5).
In the above-mentioned truly random four states modulation-demo-demodulation method of optical fiber current mutual inductor specular, in the step (4),
Specular condition is：The current modulation sequence of truly random four state modulation and the difference of the modulation amplitude of a upper modulation sequence be ±
Pi/2 or ± 3 pi/2s.
In the above-mentioned truly random four states modulation-demo-demodulation method of optical fiber current mutual inductor specular, in the step (4),
The modulation number of application is 4~10 times.
In the above-mentioned truly random four states modulation-demo-demodulation method of optical fiber current mutual inductor specular, in the step (3),
Truly random four state is modulated to persistently be produced as stochastic source by AD lowest orders AD [0], and random number is without repetition, no periodic, by random
The modulation sequence completely random of number production.
The present invention has the advantages that compared with prior art：
(1) present invention effectively improves signal to noise ratio, reduces output test current noise, improves detection sensitivity；
(2) present invention improves optical fiber current mutual inductor zero-bit output stability, and zero-bit output is non-right after suppressing electric current reversely
Title property.
Brief description of the drawings
Fig. 1 is binary states square-wave frequency modulation demodulation principle figure of the prior art；
Fig. 2 is four states Staircase wave demodulation principle figure of the prior art；
Fig. 3 is the state principles of modulation and demodulation figure of pseudorandom four of the prior art；
Fig. 4 is the optical fiber current mutual inductor overall plan schematic diagram of the present invention；
Fig. 5 is the truly random four states principles of modulation and demodulation figure of specular of the present invention；
Fig. 6 is the truly random four states modulation-demo-demodulation method flow chart of specular of the present invention.
Embodiment
The present invention is described in further detail below in conjunction with the accompanying drawings：
As shown in figure 4, light source, under driving refrigeration circuit effect, the light sent enters integrated optics by coupler A
Device, after Y waveguide integrated optical device carries out phase-modulation to light, two bunch polarised lights are exported, wherein light beam receives
Modulation, two bunch polarised lights along polarization maintaining optical fibre fast axle and slow axis by after coupler B, entering delay line respectively, then by λ/4
Wave plate is changed into two beam circularly polarized lights, wherein a branch of left-handed, another beam dextrorotation, the sensitive optical fibre into fiber optic loop is propagated,
Two beam elliptically polarized lights produce phase difference under Faraday magneto-optic effects and tested electric current collective effectTwo beams are ellipse
Circularly polarized light, which is traveled to after speculum is reflected, is again introduced into sensitive optical fibre, and former left-handed rotation is changed into right-handed rotation, and former right-handed rotation is changed into
Left-handed rotation, generate phase difference under Faraday magneto-optic effects and tested electric current collective effect againIt is now total
Phase difference variable isThe elliptically polarized light that two beams carry current information is changed into line by the wave plate of λ/4 again
Polarised light, while the linearly polarized light propagated originally along slow axis is changed into along fast axis propagation, the linearly polarized light propagated originally along slow axis becomes
To be propagated along slow axis, eventually pass back to Y waveguide integrated optical device and interfere, interference light is again by integrated optical device, coupler A
It is output to and reaches photodetector, detector converts optical signal into electric signal, sampled by A/D, right according to applied modulated signal
Data signal exports measured signal after being demodulated demodulation, while produces modulated signal, feedback staircase waveform, error feedback signal,
Finally modulated signal, staircase waveform, error feedback are commonly applied on Y waveguide device, complete digital newspaper industry.
Fig. 6 is the truly random modulation-demo-demodulation method flow chart of specular of the present invention.As shown in fig. 6, the fibre-optic current is mutual
The truly random four states modulation-demo-demodulation method of sensor specular comprises the following steps：
(1) electric on optical fiber current mutual inductor, its A/D converter starts sampling and obtains hits；
(2) A/D converter will be transferred to data demodulation module in hits in step (1), and data demodulation module is according to adopting
Lowest order AD [0] in sample number produces random sequence and Stochastic Modulation number；
(3) data demodulation module is truly random according to random sequence in step (2) and Stochastic Modulation number generation specular
Four states are modulated；
(3-1) is by the modulation of specular truly random four state is by A/D converter and discharge circuit is after-applied arrives Y waveguide.
In step (3), the truly random four states modulation of generation specular comprises the following steps：
(4) data demodulation module produces truly random four state according to random sequence and modulated, and its modulation sequence is by stochastic source AD [0]
The generating random number of output, random number is not repeated, no periodic, therefore modulation amplitude is combined by ± pi/2 or ± 3 pi/2 completely randoms
Formed.Data demodulation module carries out application modulation according to the Stochastic Modulation number in step (2), when the modulation number of application is more than
During Stochastic Modulation number in step (2), whether truly random four states modulation caused by judgement meets specular；Specular bar
Part is：The current modulation sequence of truly random four state modulation and the difference of the modulation amplitude of a upper modulation sequence be ± pi/2 or ± 3 π/
2.As shown in figure 5, current modulation sequence is the modulation applied, it is adjacent thereto applied be modulated to a modulation
Sequence, it is adjacent thereto will apply modulation for next modulation sequence.
(5) when meeting specular, by the tune of the application for the Stochastic Modulation number being more than in step (4) in step (2)
Truly random four state modulation before number processed is modulated implementation in a mirror-image fashion again, forms complete specular truly random four
State is modulated；
(6) when being unsatisfactory for specular, modulation is continued to until meeting specular condition, repeat step (5).
Specifically, in step (1) and step (2), optical fiber current mutual inductor modulation-demodulation circuit is in powered on moment, A/D
Conversion chip starts to sample, and has output in the case where whetheing there is measurement current conditions, because A/D conversion chips multidigit exports, A/D cores
Piece lowest order AD [0] is 0 and 1 random quantity, using AD [0] as random number sequence source, generates true random sequence and the random tune of setting
Number processed.
In step (3), truly random four state is modulated to the random number that Stochastic Modulation sequence is exported by stochastic source AD [0] and given birth to
Into random number is not repeated, no periodic, therefore modulation amplitude is combined and formed by ± pi/2 or ± 3 pi/2 completely randoms.
In step (4), according to random sequence, apply completely random modulation, make previous modulation sequence and next tune
The difference of modulation amplitude is ± pi/2 or ± 3 pi/2s between sequence processed, and modulation sequence modulation number is randomly set to 4~10 times or more
It is secondary.
In step (5) and step (6), after Stochastic Modulation sequence reaches setting number, progress can symmetrically judge, can be right
It is ± pi/2 or ± 3 pi/2s that Rule of judgment, which is referred to as that modulation amplitude differs between current modulation sequence and next modulation sequence,.If
Meet symmetric condition, can symmetrically judge to terminate.If being unsatisfactory for symmetric condition, random symmetric waveform is continued to, until full
Can symmetric condition, therefore a symmetrical Stochastic Modulation waveform modulated number is not fully equal to setting value.
After satisfaction can symmetrically judge, Stochastic Modulation waveform will be applied before and carry out mirror image implementation again, complete one completely
Symmetrical truly random four state modulation.After the completion of carry out next symmetrical Stochastic Modulation again, as shown in Figure 5.It is previous right in Fig. 5
The Stochastic Modulation cycle is referred to as 8 τ, and behind line of demarcation, next symmetrical Stochastic Modulation be 4 τ, modulation period according to set at random number and
It can determine whether conditional decision.
After system electrification, parameter initialization is completed, phase difference is caused by after interference as caused by Magnet-Optic Faraday Effect
Light intensity signal, electric signal is converted into by photodetector, electric signal carries out signal demodulation by A/D samplings, while produce with
Machine random sequence and Stochastic Modulation number, Stochastic Modulation waveform is produced by modulation sequence and modulation number, more than setting modulation time
Carry out symmetrically judging after number, if meeting symmetric condition, carry out mirror image Stochastic Modulation, if being unsatisfactory for symmetric condition, continue
Implement Stochastic Modulation, until meeting symmetric condition, then carry out mirror image again.The truly random four states modulation of specular is passed through into A/D
Converter and discharge circuit are after-applied on Y waveguide.The truly random four states modulation-demo-demodulation method of specular possesses symmetrical and random
Two characteristics, both there are the positive and negative ± pi/2 of square wave, ± 3 pi/2 modulation amplitude frequency of occurrence phases, there is the state of pseudorandom four again
The advantages of modulation ± pi/2, ± 3 pi/2s occur at random, and its random sequence completely random, modulation period are random, can be effective gram
Detection sensitivity caused by taking original modulator approach is poor, noise is big, zero-bit reversely asymmetric and zero fluctuation the shortcomings that.
The truly random modulation of specular as shown in figure 5, include two truly random modulating waves of complete specular altogether in Fig. 5
Shape, two complete modulation waveforms are separated with line of demarcation, and modulation waveform modulation number is 16 times before line of demarcation, and the cycle is 8 τ, and preceding 8
It is individual to be modulated to truly random modulation, behind 8 modulation be with symmetry axis to first 8 modulation carry out mirror images.Because modulation number is random
It is set as 4~10 times, therefore specular modulation number is 8 times behind line of demarcation, the cycle is 4 τ.In addition, modulation needs progress can
Symmetry judges, even if modulation number is more than setting modulation number, when being unsatisfactory for symmetrically judging, is still to continue to implement to adjust at random
System, until just mirror image implementation after meeting symmetric condition, modulation period also there is randomness.Therefore the truly random modulation of specular
The modulation sequence of demodulation method and modulation period are respectively provided with random feature.
The present invention effectively improves signal to noise ratio, reduces output test current noise, improves detection sensitivity；And the present invention carries
High optical fiber current mutual inductor zero-bit output stability, zero-bit output asymmetry after suppressing electric current reversely.
Embodiment described above is the present invention more preferably embodiment, and those skilled in the art is in this hair
The usual variations and alternatives carried out in the range of bright technical scheme should all include within the scope of the present invention.
Claims (6)
- A kind of 1. truly random four states modulation-demo-demodulation method of optical fiber current mutual inductor specular, it is characterised in that methods described Comprise the following steps：Step 1：Electric on optical fiber current mutual inductor, its A/D converter starts sampling and obtains hits；Step 2：A/D converter will be transferred to data demodulation module in hits in step 1, data demodulation module is according to hits In lowest order AD [0] produce random sequence and Stochastic Modulation number；Step 3：Data demodulation module generates truly random four state of specular according to random sequence in step 2 and Stochastic Modulation number Modulation.
- 2. the truly random four states modulation-demo-demodulation method of optical fiber current mutual inductor specular according to claim 1, it is special Sign is, also comprises the following steps：Step 3-1：The truly random four states modulation of specular is passed through into A/D converter and discharge circuit It is after-applied to arrive Y waveguide.
- 3. the truly random four states modulation-demo-demodulation method of optical fiber current mutual inductor specular according to claim 1, it is special Sign is：In the step 3, the truly random four states modulation of generation specular comprises the following steps：Step 4：Data demodulation module produces truly random four state according to random sequence and modulated, and data demodulation module is according in step 2 Stochastic Modulation number carry out application modulation, when application modulation number be more than step 2 in Stochastic Modulation number when, judge to produce Whether raw truly random four state modulation meets specular；Step 5：When meeting specular, by the modulation number of the application for the Stochastic Modulation number being more than in step 4 in step 2 Truly random four state modulation before carries out mirror image and implements to form the truly random four states modulation of specular；Step 6：When being unsatisfactory for specular, modulation is continued to until meeting specular condition, repeat step 5.
- 4. the truly random four states modulation-demo-demodulation method of optical fiber current mutual inductor specular according to claim 3, it is special Sign is：In the step 4, specular condition is：The current modulation sequence of truly random four states modulation and upper one modulation The difference of the modulation amplitude of sequence is ± pi/2 or ± 3 pi/2s.
- 5. the truly random four states modulation-demo-demodulation method of optical fiber current mutual inductor specular according to claim 3, it is special Sign is：In the step 4, the modulation number of application is 4~10 times.
- 6. the truly random four states modulation-demo-demodulation method of optical fiber current mutual inductor specular according to claim 1, it is special Sign is：In the step 3, truly random four state is modulated to persistently be produced as stochastic source by AD lowest orders AD [0], random number Without repetition, no periodic, the modulation sequence completely random produced by random number.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107422166A (en) * | 2017-08-07 | 2017-12-01 | 北京航天时代光电科技有限公司 | A kind of optical fiber current mutual inductor suppression optical power fluctuation modulation-demo-demodulation method |
| CN109631871A (en) * | 2018-12-09 | 2019-04-16 | 西安航天精密机电研究所 | A kind of cross-linked Stochastic Modulation of inhibition fibre optic gyroscope and demodulation method |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6700928B1 (en) * | 2000-05-11 | 2004-03-02 | The Boeing Company | Tetrahedron modem |
| CN1844853A (en) * | 2006-05-19 | 2006-10-11 | 北京航空航天大学 | Four-state modulation and demodulation method for automatically tracking optical fiber gyro 2pai voltage |
| CN101246009A (en) * | 2008-02-29 | 2008-08-20 | 北京航空航天大学 | Digital closed-loop optic fiber gyroscope accidental modulating method based on four-state markov chain |
| CN105911503A (en) * | 2016-07-08 | 2016-08-31 | 中国能源建设集团湖南省电力设计院有限公司 | On-line verification system for all-fiber optical current transformer |
-
2017
- 2017-08-07 CN CN201710666589.2A patent/CN107607766B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6700928B1 (en) * | 2000-05-11 | 2004-03-02 | The Boeing Company | Tetrahedron modem |
| CN1844853A (en) * | 2006-05-19 | 2006-10-11 | 北京航空航天大学 | Four-state modulation and demodulation method for automatically tracking optical fiber gyro 2pai voltage |
| CN101246009A (en) * | 2008-02-29 | 2008-08-20 | 北京航空航天大学 | Digital closed-loop optic fiber gyroscope accidental modulating method based on four-state markov chain |
| CN105911503A (en) * | 2016-07-08 | 2016-08-31 | 中国能源建设集团湖南省电力设计院有限公司 | On-line verification system for all-fiber optical current transformer |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107422166A (en) * | 2017-08-07 | 2017-12-01 | 北京航天时代光电科技有限公司 | A kind of optical fiber current mutual inductor suppression optical power fluctuation modulation-demo-demodulation method |
| CN107422166B (en) * | 2017-08-07 | 2020-02-11 | 北京航天时代光电科技有限公司 | Modulation and demodulation method for suppressing light power fluctuation for optical fiber current transformer |
| CN109631871A (en) * | 2018-12-09 | 2019-04-16 | 西安航天精密机电研究所 | A kind of cross-linked Stochastic Modulation of inhibition fibre optic gyroscope and demodulation method |
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