CN104977079A - Signal demodulation method and apparatus - Google Patents
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Abstract
The embodiment of the invention provides a signal demodulation method and apparatus. The method comprises the following steps that: first signal frames detected by a first detector and second signal frames detected by a second detector are acquired; at least one weak signal pair corresponding to the same time point in the first signal frames and the second signal frames are determined; when each weak signal pair is processed, weak signals in the first signal frames and the second signal frames in current weak signal pairs are expanded according to a first type Bessel function, so that corresponding function expansions corresponding to the weak signals in the current weak signal pairs can be obtained respectively; and phase difference generated by outside disturbance signals corresponding to the current weak signal pairs can be determined according to the function expansions, and the current weak signal pairs can be demodulated through the phase difference. With the signal demodulation schemes provided by the embodiment of the invention, the weak signals can be demodulated accurately, and therefore, the position of an intruder can be positioned accurately.
Description
Technical field
The present invention relates to signal processing technology field, particularly relate to a kind of signal demodulating method and device.
Background technology
Along with the development of society, the raising of people's security protection consciousness, all kinds of security and guard technology means are widely used.Modern conventional safety-protection system solution is as infrared point-to-point correlation scheme, fence, electrical network, induction cable and optical fiber safety-protection system.Optical fiber safety-protection system utilizes optical fiber as a kind of sensor-based system of sensor information, and optical fiber is as the medium again as optical transport while sensor information.Current optical fiber safety-protection system can monitor 40Km in real time with exterior domain, and carries out long-range and real-time warning to the accident in certain accuracy rating.
The principle of work of optical fiber safety-protection system is: optical fiber safety-protection system sends sensor fibre to defence area, and the light signal of being returned by fiber reflection by optical signal detector carries out demodulation, is positioned, and send warning message by the position of demodulation result to invader.
The core of optical fiber safety-protection system is the long-distance sensing system based on optical fiber Sagnac (Sagnac) interferometer principle, based on optical fiber Sagnac interferometer principle long-distance sensing system light path structure as shown in Figure 1.In Fig. 1, SLD is light source, C
1for circulator, C
2be 3 × 3 coupling mechanisms, M is faraday rotation mirror, P
1, P
2be respectively two-way detector.P
1, P
2the signal received mainly is divided into two classes, and the first kind is P
1, P
2middle point of crossing is not at the signal of null value, and this type of signal is referred to as strong signal; Equations of The Second Kind is P
1, P
2middle point of crossing is positioned at the signal of null position, and this type of signal is referred to as weak signal.Current signal receiving scheme, to P
1, P
2when the signal detected carries out demodulation, can't tell the men from the boys signal, but no matter all signals are that strong signal or weak signal all carry out demodulation according to differential algorithm or normalization algorithm by blindness.
And differential algorithm or normalization algorithm carry out the method for demodulation to signal, be only applicable to the demodulation of strong signal, for the demodulation of weak signal according to this method, the demodulation result accuracy obtained is low.Visible, existing this scheme of signal being carried out to demodulation, due to by all signals all blindly carry out demodulation according to differential algorithm or normalization algorithm, therefore, there is the problem low to weak signal demodulation result accuracy.Further, existing this scheme of signal being carried out to demodulation, due to low to weak signal demodulation result accuracy, and the demodulation result of weak signal is also the important privacy positioned invader, therefore, cause the most at last positioning the position of invader exactly.
Summary of the invention
Embodiments provide a kind of signal demodulating method and device, to solve current signal demodulating method, because accurate demodulation cannot be carried out to weak signal, and cause cannot exactly to the problem that the position of invader positions.
In order to solve the problem, the invention discloses a kind of signal demodulating method, comprising: the first signal frame obtaining the first detector detection, and the secondary signal frame of the second detector detection; Determine at least one weak signal pair corresponding to synchronization in described first signal frame and described secondary signal frame; To each weak signal to when processing, by current weak signal to described in weak signal in the first signal frame and described secondary signal frame launch according to Bessel function of the first kind respectively, obtain the function expansion corresponding with the weak signal of current weak signal centering respectively; By described function expansion, determine the phase differential that current weak signal produces the external disturbance signal of correspondence, by described phase differential to current weak signal to carrying out demodulation.
Preferably, describedly determine that corresponding at least one weak signal of synchronization in described first signal frame and described secondary signal frame comprises step: the signal in each moment in the signal in each moment in described first signal frame and described secondary signal frame is normalized; The signal in each moment in the described secondary signal frame after the signal in each moment in described first signal frame after normalized and normalized is compared; By synchronization and the signal being all null value after normalized is defined as a pair weak signal.
Preferably, weak signal in first signal frame of current weak signal centering and described secondary signal frame is launched according to Bessel function of the first kind respectively, the step obtaining the function expansion corresponding with current weak signal centering weak signal respectively comprises: determine the first expression formula that weak signal in described first signal frame is corresponding, and the second expression formula that weak signal in described secondary signal frame is corresponding; Determine Taylor's formula that carry out Bessel function of the first kind expansion, that launch under specified point; The Taylor's formula launched under specified point described in described first expression formula being substituted into, obtains first function expansion corresponding with the weak signal in described first signal frame; The Taylor's formula launched under specified point described in described second expression formula being substituted into, obtains second function expansion corresponding with the weak signal in described secondary signal frame.
Preferably, the first expression formula corresponding to the weak signal in described first signal frame is:
second expression formula corresponding to the weak signal in described secondary signal frame is:
wherein, described ω represents the normalized radian frequency of the outer signals disturbance that optical fiber is responded to, and t represents the moment that weak signal is corresponding, C
nrepresent normalization coefficient, represent the initial phase difference of the two-way light that the first detector and the second detector detect,
represent the external disturbance signal phase difference that the weak signal of t is corresponding; The Taylor's formula launched under specified point described in described first expression formula is substituted into, first function expansion corresponding with the weak signal in the first signal frame obtained is:
the Taylor's formula launched under specified point described in described second expression formula is substituted into, second function expansion corresponding with the weak signal in secondary signal frame obtained is:
Preferably, describedly pass through function expansion, determine that the step of the phase differential of the external disturbance signal generation that current weak signal is corresponding comprises: only retain in described first function expansion, setting exponent number item generation the 3rd function expansion, only retain in described second function expansion, setting exponent number item generation the 4th function expansion; Described 3rd function expansion and described 4th function expansion are processed, obtains the differential of described weak signal to the phase differential that the external disturbance signal of correspondence produces; Integral and calculating is carried out to described differential, obtains the phase differential that current weak signal produces the external disturbance signal of correspondence.
In order to solve the problem, the invention also discloses a kind of signal demodulating equipment, comprising: acquisition module, for obtaining the first signal frame of the first detector detection, and the secondary signal frame of the second detector detection; Determination module, for determining at least one weak signal pair corresponding to synchronization in described first signal frame and described secondary signal frame; Demodulation module, for to each weak signal to when processing, by current weak signal to described in weak signal in the first signal frame and described secondary signal frame launch according to Bessel function of the first kind respectively, obtain the function expansion corresponding with the weak signal of current weak signal centering respectively; By described function expansion, determine the phase differential that current weak signal produces the external disturbance signal of correspondence, by described phase differential to current weak signal to carrying out demodulation.
Preferably, described determination module comprises: normalization module, for being normalized the signal in each moment in the signal in each moment in described first signal frame and described secondary signal frame; Comparing module, for comparing to the signal in each moment in the described secondary signal frame after the signal in each moment in described first signal frame after normalized and normalized; Weak signal to determination module, for by synchronization and the signal being all null value after normalized is defined as a pair weak signal.
Preferably, weak signal in first signal frame of current weak signal centering and described secondary signal frame is launched according to Bessel function of the first kind by described demodulation module respectively, when obtaining the function expansion corresponding with current weak signal centering weak signal respectively: determine the first expression formula that weak signal in described first signal frame is corresponding, and the second expression formula that weak signal in described secondary signal frame is corresponding; Determine Taylor's formula that carry out Bessel function of the first kind expansion, that launch under specified point; The Taylor's formula launched under specified point described in described first expression formula being substituted into, obtains first function expansion corresponding with the weak signal in described first signal frame; The Taylor's formula launched under specified point described in described second expression formula being substituted into, obtains second function expansion corresponding with the weak signal in described secondary signal frame.
Preferably, the first expression formula corresponding to the weak signal in described first signal frame is:
second expression formula corresponding to the weak signal in described secondary signal frame is:
wherein, described ω represents the normalized radian frequency of the outer signals disturbance that optical fiber is responded to, and t represents the moment that weak signal is corresponding, C
nrepresent normalization coefficient, represent the initial phase difference of the two-way light that the first detector and the second detector detect,
represent the external disturbance signal phase difference that the weak signal of t is corresponding; The Taylor's formula launched under specified point described in described first expression formula is substituted into, first function expansion corresponding with the weak signal in the first signal frame obtained is:
the Taylor's formula launched under specified point described in described second expression formula is substituted into, second function expansion corresponding with the weak signal in secondary signal frame obtained is:
Preferably, described demodulation module passes through function expansion, when determining the phase differential of the external disturbance signal generation that current weak signal is corresponding: only retain in described first function expansion, setting exponent number item generation the 3rd function expansion, only retain in described second function expansion, setting exponent number item generation the 4th function expansion; Described 3rd function expansion and described 4th function expansion are processed, obtains the differential of described weak signal to the phase differential that the external disturbance signal of correspondence produces; Integral and calculating is carried out to described differential, obtains the phase differential that current weak signal produces the external disturbance signal of correspondence.
Compared with prior art, the present invention has the following advantages:
The signal receiving scheme that the embodiment of the present invention provides, getting acquisition first detector detection the first signal frame, and the second detector detection secondary signal frame time, first determine the weak signal pair in signal frame.Bessel function of the first kind is then adopted to launch for weak signal to i.e. weak signal, obtain the function expansion corresponding with the weak signal of current weak signal centering respectively, and then function expansion is processed, determine the phase differential that weak signal produces the external disturbance signal of correspondence.Visible, the signal receiving scheme that the embodiment of the present invention provides is when processing the signal in signal frame, weak signal and strong signal can be distinguished, and targetedly to weak signal to carrying out demodulation, owing to adopting mode effectively in the embodiment of the present invention, demodulation is carried out to weak signal, therefore, it is possible to carry out accurate demodulation to weak signal, and then can position the position of invader exactly.
Accompanying drawing explanation
Fig. 1 is fibre optic interferometer light channel structure figure;
Fig. 2 is the flow chart of steps of a kind of signal demodulating method according to the embodiment of the present invention one;
Fig. 3 is the flow chart of steps of a kind of signal demodulating method according to the embodiment of the present invention two;
Fig. 4 is the flow chart of steps adopting the signal demodulating method shown in embodiment two to carry out signal receiving;
Fig. 5 is the original waveform figure adopting the method shown in Fig. 4 to carry out the signal frame of demodulation;
Fig. 6 is after adopting the method shown in Fig. 4 to carry out demodulation to the signal frame shown in Fig. 5, the curve map of the demodulation result obtained;
Fig. 7 is after adopting existing method to carry out demodulation to the signal frame shown in Fig. 5, the curve map of the demodulation result obtained;
Fig. 8 is the structured flowchart of a kind of signal demodulating equipment according to the embodiment of the present invention three.
Embodiment
For enabling above-mentioned purpose of the present invention, feature and advantage become apparent more, and below in conjunction with the drawings and specific embodiments, the present invention is further detailed explanation.
Embodiment one
With reference to Fig. 1, show the flow chart of steps of a kind of signal demodulating method according to the embodiment of the present invention one.
The signal demodulating method of the embodiment of the present invention comprises the following steps:
Step S102: the first signal frame obtaining the first detector detection, and the secondary signal frame of the second detector detection.
Detector, after detecting signal, carries out process to signal and converts thereof into electric signal, then sends signal frame according to setpoint frequency to master control set (such as: computing machine, processing module, processor, main control module etc.).Be provided with two detectors in fibre optic interferometer light path in the present embodiment, therefore, master control set can obtain the signal frame that two detectors i.e. the first detector and the second detector send respectively.
Step S104: determine at least one weak signal pair corresponding to synchronization in the first signal frame and secondary signal frame.
In signal frame, comprise multiple signal, and each signal is to having respective signal intensity and time point and moment.Strong signal is not referred to as at the signal of null value based on point of crossing in two paths of signals, in two paths of signals, point of crossing is positioned at the signal of null position, this type of signal is referred to as the principle of weak signal, is compared by the signal of synchronization in two signal frames too, determine weak signal pair in the present embodiment.
It should be noted that, determined weak signal to only having a pair, but also may have multipair, and concrete quantity is decided by the signal in the first signal frame and secondary signal frame.
In the present embodiment, determining each weak signal in the first signal frame and secondary signal frame to rear, each signal frame is carried out to the process of subsequent step S106 and step S108.
Step S106: to each weak signal to when processing, weak signal in current weak signal centering first signal frame and secondary signal frame is launched according to Bessel function of the first kind respectively, obtains the function expansion corresponding with the weak signal of current weak signal centering respectively.
Preferably, when weak signal being launched according to Bessel function of the first kind, in Taylor's formula expression formula corresponding for weak signal substituted into, launched under specified point, then can realize function expansion weak signal being launched according to Bessel function of the first kind to obtain.
Step S108: by function expansion, determines the phase differential that current weak signal produces the external disturbance signal of correspondence, by this phase differential to weak signal to carrying out demodulation.
In the present embodiment, by above-mentioned signal demodulating method, the phase differential that external disturbance signal corresponding to each pair of weak signal in the first signal frame and secondary signal frame produces can be demodulated, then the phase differential that each corresponding to the strong signal external disturbance signal demodulated in the first signal frame and secondary signal frame by existing correlation demodulation method is produced, adopts the position of existing correlation technique to invader to position by each phase differential demodulated.
By the signal demodulating method that the present embodiment provides, getting acquisition first detector detection the first signal frame, and the second detector detection secondary signal frame time, first determine the weak signal pair in signal frame.Bessel function of the first kind is then adopted to launch for weak signal to i.e. weak signal, obtain the function expansion corresponding with the weak signal of current weak signal centering respectively, and then function expansion is processed, determine the phase differential that weak signal produces the external disturbance signal of correspondence.Visible, the signal demodulating method that the present embodiment provides, have to property to weak signal to carrying out demodulation, owing to adopting mode effectively in the present embodiment, demodulation is carried out to weak signal, therefore, it is possible to carry out accurate demodulation to weak signal, and then can position the position of invader exactly.
Embodiment two
With reference to Fig. 2, show the flow chart of steps of a kind of signal demodulating method according to the embodiment of the present invention two.
The signal demodulating method of the embodiment of the present invention specifically comprises the following steps:
Step S202: main control module obtains the first signal frame of the first detector detection, and the secondary signal frame of the second detector detection.
Comprise multiple signal in signal frame, and each signal is to having respective signal intensity and time point and moment.In the present embodiment, by the signal P in the first signal frame
1represent, by the signal P in secondary signal frame
2represent.Wherein, the first detector and the second detector synchronizing detection signal, main control module, receiving after the first detector and the second detector detect signal frame, is analyzed after two-way synchronizing signal being combined.
Step S204: the signal of main control module to each moment in the signal in each moment in the first signal frame and secondary signal frame is normalized.
Wherein, a kind of mode be preferably normalized the signal in the first signal frame is as follows:
S1: determine maximum signal value in the first signal frame, and minimum signal strength value;
S2: the signal in each moment in the first signal frame is poor with minimum signal strength value respectively, then uses difference divided by the difference of maximum signal value and minimum signal strength value, to realize being normalized the signal in each moment in the first signal frame.
Such as: the signal intensity of three signals comprised in the first signal frame is respectively 3,4 and 5, so, when being normalized first signal, then it is (3-3)/(5-3)=0, correspondingly, the result after other two signal normalization process is respectively 1/2,1.
Adopt and can be normalized the signal in each moment in secondary signal frame the mode that the signal in the first signal frame is normalized.
Step S206: the signal of main control module to each moment in the secondary signal frame after the signal in each moment in the first signal frame after normalized and normalized is compared, by synchronization and the signal being all null value after normalized is defined as a pair weak signal.
It should be noted that, may there is multiple weak signal pair in secondary signal frame, also only may there is a weak signal pair in the first signal frame, concrete number depends on the signal intensity in the first signal frame and secondary signal frame.
In the present embodiment, determine in the first signal frame with each pair of weak signal in secondary signal frame after, respectively each pair of weak signal is handled as follows.
Step S208: main control module to when processing, determines the first expression formula that weak signal in the first signal frame is corresponding to current weak signal, and the second expression formula that weak signal in secondary signal frame is corresponding.
First expression formula corresponding to the weak signal in the first signal frame is:
second expression formula corresponding to the weak signal in secondary signal frame is:
Wherein, ω represents the normalized radian frequency of the outer signals disturbance that optical fiber is responded to, and t represents the moment that weak signal is corresponding, C
nrepresent normalization coefficient, represent the initial phase difference of the two-way light that the first detector and the second detector detect,
represent the external disturbance signal phase difference that the weak signal of t is corresponding.
It should be noted that, in specific implementation process, C
nvalue can be arranged according to the actual requirements by those skilled in the art, such as: be arranged to 1,2,3 etc., the present embodiment does not do concrete restriction to this.
Step S210: main control module determines Taylor's formula that carry out Bessel function of the first kind expansion, that launch under specified point.
Wherein, Taylor's formula is
When the Taylor's formula launched under specified point is a=0, the expansion after Taylor's formula conversion.
Step S212: the first expression formula is substituted into the Taylor's formula launched under specified point by main control module, obtains first function expansion corresponding with the weak signal in the first signal frame; Second expression formula is substituted into the Taylor's formula launched under specified point, obtain second function expansion corresponding with the weak signal in secondary signal frame.
First expression formula is substituted into the Taylor's formula launched under specified point, first function expansion corresponding with the weak signal in the first signal frame obtained is:
The Taylor's formula launched under specified point described in second expression formula is substituted into, second function expansion corresponding with the weak signal in secondary signal frame obtained is:
Step S214: main control module only retains in the first function expansion, setting exponent number item generation the 3rd function expansion, only retains in the second function expansion, setting exponent number item generation the 4th function expansion.
Wherein, setting exponent number item can be arranged according to the actual requirements by those skilled in the art, such as: be arranged to only retain first three rank item, higher order term later for three rank items is ignored, again such as: be arranged to only retain front quadravalence item, high-order later for quadravalence item is ignored, certainly, only can also retain the first five rank item or only retain front two rank items etc.
Preferably, be arranged to only retain first three rank item, ignored by higher order term later for three rank items, the 3rd function expansion ignoring rear generation is:
4th function expansion is:
Step S216: main control module processes the 3rd function expansion and the 4th function expansion, obtains the differential of weak signal to the phase differential that the external disturbance signal of correspondence produces.
One preferably processes the 3rd function expansion and the 4th function expansion, obtains the mode of weak signal to the differential of the phase differential that the external disturbance signal of correspondence produces as follows:
S1, is added the 3rd function expansion with the 4th function expansion, obtains the first function expression;
That is:
S2, subtracts each other the 3rd function expansion and the 4th function expansion, obtains the second function expression;
That is:
S3, differentiates the second function expression;
The functional expression obtained is:
S4, adopts the first function expression to obtain
(10) are substituted into (11) and obtain by S5
It should be noted that, in specific implementation process, to be not limited in the present embodiment cited, the 3rd function expansion and the 4th function expansion are done poor and.Concrete processing procedure, can be determined according to the actual requirements by those skilled in the art.
Step S218: carry out integral and calculating to differential, obtains the phase differential that current weak signal produces the external disturbance signal of correspondence.
The phase differential that current weak signal produces the external disturbance signal of correspondence
expression formula be:
In concrete computation process, if the coupling mechanism in fibre optic interferometer is 3 × 3 coupling mechanisms, then by φ
0be set to
preferably, by C
nbe set to 1, can calculating be simplified like this.
In the present embodiment, by above-mentioned signal demodulating method, the phase differential that external disturbance signal corresponding to each pair of weak signal in the first signal frame and secondary signal frame produces can be demodulated, then the phase differential that each corresponding to the strong signal external disturbance signal demodulated in the first signal frame and secondary signal frame by existing correlation demodulation method is produced, adopts the position of existing correlation technique to invader to position by each phase differential demodulated.Such as: perform following treatment scheme successively to each phase differential that demodulation obtains: digital filtering, spectrum analysis, curve, wavelet analysis, look for depression points, after determining depression points, position corresponding to depression points is the position of invader.
By the signal demodulating method that the present embodiment provides, getting acquisition first detector detection the first signal frame, and the second detector detection secondary signal frame time, first determine the weak signal pair in signal frame.Bessel function of the first kind is then adopted to launch for weak signal to i.e. weak signal, obtain the function expansion corresponding with the weak signal of current weak signal centering respectively, and then function expansion is processed, determine the phase differential that weak signal produces the external disturbance signal of correspondence.Visible, the signal demodulating method that the present embodiment provides, have to property to weak signal to carrying out demodulation, owing to adopting mode effectively in the present embodiment, demodulation is carried out to weak signal, therefore, it is possible to carry out accurate demodulation to weak signal, and then can position the position of invader exactly.
Be described with the demodulation method of an instantiation to the optical fibre vibration sensor feeble signal of the present embodiment below, idiographic flow is see accompanying drawing 4.As shown in Figure 4, the demodulation method of the optical fibre vibration sensor feeble signal of the present embodiment comprises the following steps:
Step S402: preprocessed data.
To the first signal frame, and secondary signal frame carries out pre-service, and wherein, pre-service can comprise the first signal framing and secondary signal framing that intercept setting-up time section.
Step S404: each signal in the first signal frame is normalized.
Step S406: each signal in secondary signal frame is normalized.
It should be noted that, step S406 is not limited to and performs after step S404, can perform before step S404, can also with step S404 executed in parallel.
In the first signal frame after normalized with the oscillogram in secondary signal frame as shown in Figure 5.
Particularly can see correlation process method in embodiment two to the method for signal frame process.In this instantiation, the signal in each moment in the secondary signal frame after the signal in each moment in the first signal frame after normalized and normalized is compared, by synchronization and the signal being all null value after normalized is defined as a pair weak signal.
In this instantiation, determine in the first signal frame with each pair of weak signal in secondary signal frame after, respectively each pair of weak signal is handled as follows.
Step S408: to the weak signal in the first signal frame according to series expansion.
Step S410: to the weak signal in secondary signal frame according to series expansion.
For in step S408 and step S410 to the concrete grammar of weak signal according to series expansion, can not repeat them here to step S214 see step S208 in embodiment two.
Step S412: the series expansion obtained in step S408 and step S410 is added.
In this step, the first function expression is obtained after the series expansion obtained in step S408 and step S410 being added.
Step S414: the series expansion obtained in step S408 and step S410 is subtracted each other.
In this step, the second function expression is obtained after the series expansion obtained in step S408 and step S410 being added.
Step S416: adopt the first function expression to obtain
For how to obtain
can obtain see the associated expression in embodiment two.
Step S418: the second function expression is differentiated.
Step S420: obtained by step S416 and step S418
expression formula and differential expressions obtain
Step S422: to the differential obtained
carry out integral and calculating, obtain the phase differential that current weak signal produces the external disturbance signal of correspondence.
In this instantiation, by above-mentioned signal demodulating method, the phase differential that external disturbance signal corresponding to each pair of weak signal in the first signal frame and secondary signal frame produces can be demodulated, then the phase differential that each corresponding to the strong signal external disturbance signal demodulated in the first signal frame and secondary signal frame by existing correlation demodulation method is produced, adopts the position of existing correlation technique to invader to position by each phase differential demodulated.Such as: perform following treatment scheme successively to each phase differential that demodulation obtains: digital filtering, spectrum analysis, curve, wavelet analysis, look for depression points, after determining depression points, position corresponding to depression points is the position of invader.After the method shown in Fig. 4 of employing carries out demodulation to the signal frame shown in Fig. 5, the curve map of the demodulation result obtained as shown in Figure 6.Correspondingly, if adopt existing method to carry out demodulation to the signal frame shown in Fig. 5, so, the curve map of the demodulation result obtained as shown in Figure 7.
Embodiment three
With reference to Fig. 8, show the structured flowchart of a kind of signal demodulating equipment of the embodiment of the present invention three.
Signal demodulating equipment in the present embodiment can be applied to optical fiber warning system, and the signal demodulating equipment in the present embodiment comprises: acquisition module 802, for obtaining the first signal frame of the first detector detection, and the secondary signal frame of the second detector detection; Determination module 804, for determining at least one weak signal pair corresponding to synchronization in the first signal frame and secondary signal frame; Demodulation module 806, for to each weak signal to when processing, weak signal in current weak signal centering first signal frame and secondary signal frame is launched according to Bessel function of the first kind respectively, obtains the function expansion corresponding with the weak signal of current weak signal centering respectively; By function expansion, determine the phase differential that current weak signal produces the external disturbance signal of correspondence, by phase differential to current weak signal to carrying out demodulation.
Preferably, determination module 804 comprises: normalization module 8042, for being normalized the signal in each moment in the signal in each moment in the first signal frame and secondary signal frame; Comparing module 8044, for comparing to the signal in each moment in the secondary signal frame after the signal in each moment in the first signal frame after normalized and normalized; Weak signal to determination module 8046, for by synchronization and the signal being all null value after normalized is defined as a pair weak signal.
Preferably, weak signal in first signal frame of current weak signal centering and secondary signal frame is launched according to Bessel function of the first kind by demodulation module 806 respectively, when obtaining the function expansion corresponding with current weak signal centering weak signal respectively: determine the first expression formula that weak signal in the first signal frame is corresponding, and the second expression formula that weak signal in secondary signal frame is corresponding; Determine Taylor's formula that carry out Bessel function of the first kind expansion, that launch under specified point; First expression formula is substituted into the Taylor's formula launched under specified point, obtain first function expansion corresponding with the weak signal in the first signal frame; Second expression formula is substituted into the Taylor's formula launched under specified point, obtain second function expansion corresponding with the weak signal in secondary signal frame.
Preferably, the first expression formula corresponding to the weak signal in the first signal frame is:
second expression formula corresponding to the weak signal in secondary signal frame is:
wherein, ω represents the normalized radian frequency of the outer signals disturbance that optical fiber is responded to, and t represents the moment that weak signal is corresponding, C
nrepresent normalization coefficient, represent the initial phase difference of the two-way light that the first detector and the second detector detect,
represent the external disturbance signal phase difference that the weak signal of t is corresponding; First expression formula is substituted into the Taylor's formula launched under specified point, first function expansion corresponding with the weak signal in the first signal frame obtained is:
second expression formula is substituted into the Taylor's formula launched under specified point, second function expansion corresponding with the weak signal in secondary signal frame obtained is
Preferably, demodulation module 806 passes through function expansion, when determining the phase differential of the external disturbance signal generation that current weak signal is corresponding: only retain in the first function expansion, setting exponent number item generation the 3rd function expansion, only retain in the second function expansion, setting exponent number item generation the 4th function expansion; 3rd function expansion and the 4th function expansion are processed, obtains the differential of weak signal to the phase differential that the external disturbance signal of correspondence produces; Integral and calculating is carried out to differential, obtains the phase differential that current weak signal produces the external disturbance signal of correspondence.
The signal demodulating equipment of the present embodiment is used for realizing corresponding signal demodulating method in previous embodiment one, embodiment two, and has the beneficial effect of corresponding embodiment of the method, does not repeat them here.
Each embodiment in this instructions all adopts the mode of going forward one by one to describe, and what each embodiment stressed is the difference with other embodiments, between each embodiment identical similar part mutually see.For system embodiment, due to itself and embodiment of the method basic simlarity, so description is fairly simple, relevant part illustrates see the part of embodiment of the method.
Above to a kind of signal demodulating method provided by the present invention and device, be described in detail, apply specific case herein to set forth principle of the present invention and embodiment, the explanation of above embodiment just understands method of the present invention and core concept thereof for helping; Meanwhile, for one of ordinary skill in the art, according to thought of the present invention, all will change in specific embodiments and applications, in sum, this description should not be construed as limitation of the present invention.
Claims (10)
1. a signal demodulating method, is characterized in that, comprising:
Obtain the first signal frame of the first detector detection, and the secondary signal frame of the second detector detection;
Determine at least one weak signal pair corresponding to synchronization in described first signal frame and described secondary signal frame;
To each weak signal to when processing, by current weak signal to described in weak signal in the first signal frame and described secondary signal frame launch according to Bessel function of the first kind respectively, obtain the function expansion corresponding with the weak signal of current weak signal centering respectively; By described function expansion, determine the phase differential that current weak signal produces the external disturbance signal of correspondence, by described phase differential to current weak signal to carrying out demodulation.
2. method according to claim 1, is characterized in that, describedly determines that corresponding at least one weak signal of synchronization in described first signal frame and described secondary signal frame comprises step:
The signal in each moment in the signal in each moment in described first signal frame and described secondary signal frame is normalized;
The signal in each moment in the described secondary signal frame after the signal in each moment in described first signal frame after normalized and normalized is compared;
By synchronization and the signal being all null value after normalized is defined as a pair weak signal.
3. method according to claim 1 and 2, it is characterized in that, weak signal in first signal frame of current weak signal centering and described secondary signal frame launched according to Bessel function of the first kind respectively, the step obtaining the function expansion corresponding with current weak signal centering weak signal respectively comprises:
Determine the first expression formula that weak signal in described first signal frame is corresponding, and the second expression formula that weak signal in described secondary signal frame is corresponding;
Determine Taylor's formula that carry out Bessel function of the first kind expansion, that launch under specified point;
The Taylor's formula launched under specified point described in described first expression formula being substituted into, obtains first function expansion corresponding with the weak signal in described first signal frame; The Taylor's formula launched under specified point described in described second expression formula being substituted into, obtains second function expansion corresponding with the weak signal in described secondary signal frame.
4. method according to claim 3, is characterized in that,
First expression formula corresponding to the weak signal in described first signal frame is:
Second expression formula corresponding to the weak signal in described secondary signal frame is:
Wherein, described ω represents the normalized radian frequency of the outer signals disturbance that optical fiber is responded to, and t represents the moment that weak signal is corresponding, C
nrepresent normalization coefficient, represent the initial phase difference of the two-way light that the first detector and the second detector detect,
represent the external disturbance signal phase difference that the weak signal of t is corresponding;
The Taylor's formula launched under specified point described in described first expression formula is substituted into, first function expansion corresponding with the weak signal in the first signal frame obtained is:
The Taylor's formula launched under specified point described in described second expression formula is substituted into, second function expansion corresponding with the weak signal in secondary signal frame obtained is:
5. method according to claim 4, is characterized in that, described by function expansion, determines that the step of the phase differential of the external disturbance signal generation that current weak signal is corresponding comprises:
Only retain in described first function expansion, setting exponent number item generation the 3rd function expansion, only retain in described second function expansion, setting exponent number item generation the 4th function expansion;
Described 3rd function expansion and described 4th function expansion are processed, obtains the differential of described weak signal to the phase differential that the external disturbance signal of correspondence produces;
Integral and calculating is carried out to described differential, obtains the phase differential that current weak signal produces the external disturbance signal of correspondence.
6. a signal demodulating equipment, is characterized in that, comprising:
Acquisition module, for obtaining the first signal frame of the first detector detection, and the secondary signal frame of the second detector detection;
Determination module, for determining at least one weak signal pair corresponding to synchronization in described first signal frame and described secondary signal frame;
Demodulation module, for to each weak signal to when processing, by current weak signal to described in weak signal in the first signal frame and described secondary signal frame launch according to Bessel function of the first kind respectively, obtain the function expansion corresponding with the weak signal of current weak signal centering respectively; By described function expansion, determine the phase differential that current weak signal produces the external disturbance signal of correspondence, by described phase differential to current weak signal to carrying out demodulation.
7. device according to claim 6, is characterized in that, described determination module comprises:
Normalization module, for being normalized the signal in each moment in the signal in each moment in described first signal frame and described secondary signal frame;
Comparing module, for comparing to the signal in each moment in the described secondary signal frame after the signal in each moment in described first signal frame after normalized and normalized;
Weak signal to determination module, for by synchronization and the signal being all null value after normalized is defined as a pair weak signal.
8. the device according to claim 6 or 7, it is characterized in that, weak signal in first signal frame of current weak signal centering and described secondary signal frame is launched according to Bessel function of the first kind by described demodulation module respectively, when obtaining the function expansion corresponding with current weak signal centering weak signal respectively:
Determine the first expression formula that weak signal in described first signal frame is corresponding, and the second expression formula that weak signal in described secondary signal frame is corresponding;
Determine Taylor's formula that carry out Bessel function of the first kind expansion, that launch under specified point;
The Taylor's formula launched under specified point described in described first expression formula being substituted into, obtains first function expansion corresponding with the weak signal in described first signal frame; The Taylor's formula launched under specified point described in described second expression formula being substituted into, obtains second function expansion corresponding with the weak signal in described secondary signal frame.
9. device according to claim 8, is characterized in that,
First expression formula corresponding to the weak signal in described first signal frame is:
Second expression formula corresponding to the weak signal in described secondary signal frame is:
Wherein, described ω represents the normalized radian frequency of the outer signals disturbance that optical fiber is responded to, and t represents the moment that weak signal is corresponding, C
nrepresent normalization coefficient, represent the initial phase difference of the two-way light that the first detector and the second detector detect,
represent the external disturbance signal phase difference that the weak signal of t is corresponding;
The Taylor's formula launched under specified point described in described first expression formula is substituted into, first function expansion corresponding with the weak signal in the first signal frame obtained is:
The Taylor's formula launched under specified point described in described second expression formula is substituted into, second function expansion corresponding with the weak signal in secondary signal frame obtained is:
10. device according to claim 9, is characterized in that, described demodulation module passes through function expansion, when determining the phase differential of the external disturbance signal generation that current weak signal is corresponding:
Only retain in described first function expansion, setting exponent number item generation the 3rd function expansion, only retain in described second function expansion, setting exponent number item generation the 4th function expansion;
Described 3rd function expansion and described 4th function expansion are processed, obtains the differential of described weak signal to the phase differential that the external disturbance signal of correspondence produces;
Integral and calculating is carried out to described differential, obtains the phase differential that current weak signal produces the external disturbance signal of correspondence.
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