CN105812023A - Sequence cross correlation property-based spectrum spreading and modulating as well as spectrum despreading and demodulating method and device - Google Patents
Sequence cross correlation property-based spectrum spreading and modulating as well as spectrum despreading and demodulating method and device Download PDFInfo
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Abstract
The invention relates to a sequence cross correlation property-based spread spectrum modulation as well as spectrum despreading and demodulating method and device. The spectrum spreading and modulating method comprises the following spectrum spreading steps: a sequence pair which is high in autocorrelation and small in cross correlation is generated; a first numerical code of original information is subjected to spectrum spreading operation with a first sequence of the sequence pair being used as a spectrum spreading code word, and a second numerical code of the original information is subjected to the spectrum spreading operation with a second sequence of the sequence pair being used as the spectrum spreading code word. The first numerical code of the original information data is subjected to the spectrum spreading operation with the first sequence being used as the spectrum spreading code word via a transmitter, and the second numerical code of the original information data is subjected to the spectrum spreading operation with the second sequence being used as the spectrum spreading code word. According to the spectrum despreading and demodulating method, correlation operation can be conducted with the first sequence being used as a local spectrum despreading code word, and two spectrum despreading states that are a correlated state and an uncorrelated state can be obtained. The sequence cross correlation property-based spectrum spreading and modulating as well as spectrum despreading and demodulating method and device can help solve a problem of reliability in power line carrier communication, and no synchronization loop is needed.
Description
Technical field
The present invention relates to power line carrier communication (PLC) field, especially relate to a kind of band spectrum modulation based on Cross-correlations of Sample Sequences and despreading demodulation method and device.
Background technology
One of key technology that power line carrier communication (PLC) technology is applied as intelligent grid and Internet of Things, enjoying global concern in recent years, the communication how realizing low cost and high reliability under severe power line channel environment is always up the technical barrier in this field.Owing to low-voltage power line network topology structure is complicated, the electrical appliance (being called load) accessing electrical network is various and random so that power line channel noise bad environments, and presents stronger time variation.On the other hand, existing electrical network is utilized to be in that it relatively low realizes cost as the big advantage that carrier communicates.Therefore spread spectrum and the mode of single-carrier modulated demodulation it mostly is at present in the communication system of low-voltage power line field maturation application.The technical combinations being most frequently with is that baseband direct sequence spread spectrum (DS-SS) is modulated in conjunction with radio frequency FSK or PSK.This is combined through the spread spectrum to message sequence, to pay the related gain after certain transmitted bandwidth exchanges reception signal despreading for for cost, it is possible to reduce system to a certain extent and reach signal to noise ratio (SNR) condition needed for same payload rates.
In actual applications, particularly under severe power line channel environment, conventional communication system has the disadvantage that, receiver utilizes the autocorrelation performance that spreading code is strong to recover size and the symbol of base-band information soft value from demodulation signal.This mode is recovered the quality of signal and is depended on that system sending and receiving end is at phase place, frequency and temporal synchronization extent.Receiver generally requires to be paid higher one-tenth and originally realized the circuit such as accurate carrier phase synchronization, Frequency Synchronization, spreading code phase capturing and tracking to carry out the recovery of signal synchronizing information.These synchronization loops with feedback under power line channel adverse circumstances because signal to noise ratio is relatively low, noise change violent etc. because usually easily there is losing lock and concussion, cause system instability, communication performance sharply declines；After causing despreading time serious, auto-correlation soft value symbol overturns or locks onto by mistake pseudo-peak, causes judgement error code.Thus greatly reducing the reliability of electric line communication system, and it is being implemented as present aspect without any advantage.
Summary of the invention
The technical problem to be solved is to provide a kind of band spectrum modulation based on Cross-correlations of Sample Sequences and despreading demodulation method and device, to solve the integrity problem of power line carrier communication, simultaneously without any synchronization loop.
The present invention solves that above-mentioned technical problem employed technical scheme comprise that a kind of spread spectrum modulation technique of proposition, including utilizing spreading code, raw information is carried out the step of spread spectrum, with the step that the data after spread spectrum are modulated, wherein said spreading step comprises the following steps: produce the sequence pair that autocorrelation is excellent and cross correlation is less；And as spread spectrum code word, the first number of described raw information is carried out spread spectrum with the First ray of described sequence pair, as spread spectrum code word, the second number of described raw information is carried out spread spectrum by the second sequence of described sequence pair.
In one embodiment of this invention, described sequence pair meets: the autocorrelation spectrum in the described First ray cycle presents sharp-pointed single-peak response: absolute value=1, normalized autocorrelation peak and only occurring once, all the other secondary lobes absolute value < 0.2；The coherence spectra bounded of two sequences, normalized crosscorrelation absolute value < 0.3.
In one embodiment of this invention, described sequence pair is that the m-sequence produced by different primitive polynomials for a pair is preferably right.
In one embodiment of this invention, described sequence pair be Gold sequence to or Golay complementary series pair.
In one embodiment of this invention, described sequence preferably to the second sequence be full 0 sequence.
The present invention proposes a kind of despread-and-demodulation method, including the step being demodulated to received signal, it is filtered producing I to demodulation signal, the filter step of Q two-way baseband signal, and to described I, Q two-way baseband signal carries out the step de-spread, wherein said spreading steps includes: produce this locality despreading code word, it is excellent that described local despreading code word is chosen from an autocorrelation, and the First ray in the less sequence pair of cross correlation, in raw information in wherein said reception signal, first number is that the First ray with described sequence pair carries out spread spectrum as spread spectrum code word, second number be by the second sequence of described sequence pair as spread spectrum code word to carrying out spread spectrum；And respectively described I, Q two-way baseband signal is de-spread by described local despreading code word.
In one embodiment of this invention, the step respectively described I, Q two-way baseband signal de-spread by described local despreading code word includes: carries out I road related operation with described local despreading code word and I roadbed band signal, and carries out Q road related operation by described local despreading code word with Q roadbed band signal simultaneously；Described I road correlation result is carried out squared computing, obtains I road despread signal；Simultaneously to the squared computing of correlation result of described Q road, obtain Q road despread signal；Described I road despread signal and described Q road despread signal are carried out addition and obtain correlation energy total value；And described correlation energy total value is normalized computing, obtain normalization correlation energy.
In one embodiment of this invention, the step respectively described I, Q two-way baseband signal de-spread by described local despreading code word also includes: described normalized energy is set a normalization threshold value and makes decisions；In each code word period of described local despreading code word, when described normalization correlation energy value exceedes described normalization threshold value, adjudicate as described first digital；And when described normalization correlation energy value is lower than described normalization threshold value, adjudicate as described second digital.
In one embodiment of this invention, the step respectively described I, Q two-way baseband signal de-spread by described local despreading code word includes: carries out I road related operation with described local despreading code word and I roadbed band signal, and carries out Q road related operation by described local despreading code word with Q roadbed band signal simultaneously；Described I road correlation result is asked signed magnitude arithmetic(al), obtains I road despread signal；Described Q road correlation result is asked signed magnitude arithmetic(al) simultaneously, obtain Q road despread signal；And described I road despread signal and described Q road despread signal are carried out addition and obtain correlation energy total value.
In one embodiment of this invention, the step respectively described I, Q two-way baseband signal de-spread by described local despreading code word also includes: described correlation energy total value is set a threshold value and makes decisions；In each code word period of described local despreading code word, when described correlation energy total value exceedes described threshold value, adjudicate as described first digital；And when described correlation energy total value is lower than described threshold value, adjudicate as described second digital.
The present invention also proposes a kind of band spectrum modulation device, including spreading code generator, generates a pair autocorrelation excellent, and the less sequence pair of cross correlation is as spread spectrum code word；Spectrum-spreading unit, receive the sequence pair that described spreading code generator generates, as spread spectrum code word, the first number of described raw information is carried out spread spectrum with the First ray of described sequence pair, as spread spectrum code word, the second number of described raw information is carried out spread spectrum by the second sequence of described sequence pair；Base band formed filter, is shaped filtering to the signal after described spectrum-spreading unit spread spectrum；Carrier generator, generates modulation Yong mono-tunnel carrier signal；And modulating unit, utilize described sinusoidal carrier signal that the signal after described base band formed filter is modulated.
The present invention also proposes a kind of despread-and-demodulation device, including: local carrier generator, generate mutually orthogonal a pair carrier signal that solution is called；Demodulating unit, utilizes the pair of mutually orthogonal carrier signal to be demodulated to received signal, output I, Q two-way demodulation signal；Low pass filter, demodulates signal to described I, Q two-way and carries out low-pass filtering, export I, Q two-way baseband signal；Local solution extended code generator, produce this locality despreading code word, described local despreading code word is chosen from the First ray in the sequence pair that an autocorrelation is excellent and cross correlation is less, in raw information in wherein said reception signal, first number is that the First ray with described sequence pair carries out spread spectrum as spread spectrum code word, the second number be by the second sequence of described sequence pair as spread spectrum code word to carrying out spread spectrum；And despread unit, receive the described local this locality despreading code word solving the generation of extended code generator, utilize described local despreading code word respectively described I, Q two-way baseband signal to be de-spread.
The second number in original information data, owing to the first number in original information data being carried out spread spectrum using First ray as spread spectrum code word at transmitter, is carried out spread spectrum using the second sequence as spread spectrum code word by the spread spectrum modulation technique of the present invention；And at receiver, de-spreading code word using First ray as this locality carries out related operation, it is possible to obtain two kinds of despreading states: " being correlated with " and " uncorrelated ", when the correlation energy value in each code word period exceedes certain thresholding, judgement is the first number；The correlation not having thresholding occurs, then can adjudicate is the second number.This judgement mode does not rely on accurate synchronization, thus can omit synchronization loop, reduces and realizes cost.
Accompanying drawing explanation
For the above-mentioned purpose of the present invention, feature and advantage can be become apparent, below in conjunction with accompanying drawing, the specific embodiment of the present invention is elaborated, wherein:
Fig. 1 illustrates communication system population structure block diagram according to embodiments of the present invention.
Fig. 2 illustrates the communication system transmitter structured flowchart of first embodiment of the invention.
Fig. 3 illustrates the communication system receiver structured flowchart of first embodiment of the invention.
Fig. 4 illustrates the communication system receiver structured flowchart of second embodiment of the invention.
Fig. 5 illustrates the communication system transmitter structured flowchart of third embodiment of the invention.
Detailed description of the invention
Below in conjunction with accompanying drawing embodiment, the present invention is described in further detail.
Fig. 1 illustrates communication system population structure block diagram according to embodiments of the present invention, and with reference to shown in Fig. 1, the communication system of the present embodiment includes transmitter and receiver.Transmitter includes spectrum-spreading unit 101 and modulating unit 102, and information data coupled to power line channel 103 after spread spectrum, modulation and is transmitted.Receiver includes demodulating unit 104, despread unit 105 and energy decision unit 106, finally recovers raw information.
Need when transmitter carries out spread spectrum to use sequence as spread spectrum code word.Mainly utilize autocorrelation performance to provide isometric a pair sequence possessing special correlation properties as spread spectrum code word the difference is that, embodiments of the invention with conventional spread spectrum code word, meet following two condition simultaneously:
Autocorrelation spectrum in one code word period presents sharp-pointed single-peak response: absolute value=1, normalized autocorrelation peak and only occurring once, all the other secondary lobes absolute value < 0.2；
The coherence spectra bounded of two code words, normalized crosscorrelation absolute value < 0.3.
Two spread spectrum codes CaAnd CbThe coherence spectra of complete cycle can be defined by following formula:
Wherein N is code word size.Work as Cb=CaTime, namely above formula becomes autocorrelation spectrum.
For m-sequence, according to its character, autocorrelation spectrum is two-value, is given by:
The autocorrelation performance of visible m-sequence is excellent, presents sharply unimodal, meets above-mentioned spread spectrum code word and chooses condition 1.；But the cross correlation between any two m-sequence is not necessarily all fine, its coherence spectra be probably three values, four values or many-valued, cross correlation value is not of uniform size.
2. embodiments of the invention choose condition according to described frequency code word, concentrate at m-sequence, and search selects the m-sequence produced by different primitive polynomials preferably to C a pairaAnd Cb, the coherence spectra of such special m-sequence pair is three values, and these three value is:
Here:
Wherein, the cycle of sequence is N=2n-1。
CaAnd CbBe m-sequence preferably to sufficient condition as follows:
During to 4 delivery, n ≠ 0；Namely n is odd number or n=2 during to 4 delivery；
Cb=CaQ (), wherein q is odd number value q=2k+ 1 or q=22k-2k+ 1:
Wherein gcd is for taking greatest common divisor.
Such as, when taking n=5, N=31, the m-sequence chosen according to conditions above is preferably to CaAnd Cb, for arbitrary phase shift, its coherence spectra is all three values, for:And maximum normalized crosscorrelation absolute value < 0.3.
Visible, now CaAnd Cb1. and 2. meet two spreading codes of the present invention simultaneously and choose condition.Namely for CaSequence, has been provided simultaneously with the excellent autocorrelation to self, and to CbThe less cross correlation of sequence.
Therefore, what the embodiment of the present invention provided is different from the method for conventional usual direct sequence spread spectrum is: at transmitter, first in original information data is digital, for instance " 1 " is with CaSequence carries out spread spectrum as spread spectrum code word, second in original information data is digital, for instance " 0 " is with CbSequence carries out spread spectrum as spread spectrum code word；And at receiver, with CaSequence de-spreads code word as this locality and carries out related operation, it is possible to obtains two kinds of despreading states: " being correlated with " and " uncorrelated ", when the correlation energy value in each code word period exceedes certain thresholding, adjudicates as information " 1 "；The correlation not having thresholding occurs, then can adjudicate as information " 0 ".
Spread spectrum code word in approach described above is chosen, it is possible to be m-sequence preferably to, Gold sequence to or Golay complementary series equity meet described spreading code simultaneously and choose condition special sequence 1. and 2..
Each embodiment of the present invention described in detail below.
First embodiment
The present embodiment in actual applications, the consideration according to data rate, the selection of work clock and the aspect such as implementation complexity and cost, select a pair length be the m-sequence of 31 preferably to as spread spectrum code word, generator polynomial is G respectivelya(x)=x5+x2+ 1 and Gb(x)=x5+x4+x3+x2+1。
For BPSK modulation system, specifically comprise following processing procedure:
Fig. 2 illustrates the communication system transmitter structured flowchart of first embodiment of the invention.With reference to shown in Fig. 2, transmitter 200 includes spectrum-spreading unit 201, spreading code generator 202, base band formed filter 203, modulating unit 204 and carrier generator 205.Spectrum-spreading unit 201, base band formed filter 203 and modulating unit 204 are sequentially connected with.Spreading code generator 202 connects spectrum-spreading unit 201, and carrier generator 205 connects modulating unit 204.
First, it is assumed that binary information sequence to be sent is s (t), spreading code generator 202 generates the m-sequence of two-way 31-bit length preferably to CaAnd Cb1. and 2., and meet aforementioned spread spectrum code word simultaneously and choose condition.
Make spread spectrum code word Carrier modulation frequency is fc, then information data transmitting signal after spectrum-spreading unit 201, base band formed filter 203, modulating unit 204 process is:
T (t)=Css·cos(2πfct)
Fig. 3 illustrates the communication system receiver structured flowchart of first embodiment of the invention.With reference to shown in Fig. 3, receiver 300 includes demodulating unit 301 and 303, local carrier generator 302, low pass filter 304 and 305, despread unit 306 and 308, local solution extended code generator 307, squarer 309 and 310, adder 311, normalization unit 312 and threshold judgement unit 313.
Receiver 300 transmits through power line channel, and the reception signal entering receiver is:
WhereinFor sending the phase distortion that signal produces after transmission, Δ f is frequency deviation.The computing of demodulated unit 301,303, output I, Q two-way demodulation signal:
Through low pass filter 304,305, after filtering radio-frequency component, obtain I, Q two-way baseband signal:
Through despread unit 306,308, carry out related operation, obtain I, Q two-way despread signal:
Wherein CdessCode word is de-spread for receiver this locality.OrderFor despreading correlation.
In conventional conventional techniques, the spread spectrum codes C of transmitterssSolution extended code C with receiverdessFor same group of code word, receiver must by the circuit such as spread spectrum code acquisition and bit synchronization tracking, and when making sending and receiving code bit Complete Synchronization, despreading correlation R reaches maximum.Therefore receiver generally also includes the carrier synchronization restoring circuits such as NCO, phase discriminator, loop filter, descriminator in the past, when making the phase place of receiver local carrier, frequency with the signal Complete Synchronization received by loop feedback adjustment, just hasΔ f=0, so time:
M (t)=R cos (0)=R
N (t)=R sin (0)=0
Transmission information s (t) can be obtained after I road despreading output M (t) soft value is carried out threshold judgement.
Visible, previous methods, could undistorted recovery raw information s (t) only when communication system reaches precise synchronization.But when communication system not exclusively synchronizes, namelyDuring Δ f ≠ 0, result above is also false.
In actual applications, communication system net synchronization capability is often along with the severe degree of noise circumstance sharply declines, under Low SNR, there is the problem influencing each other and being difficult to reach ideal stability state in the loop such as codeword bit synchronization, carrier phase synchronization, Frequency Synchronization.Chip delay phase place,There is error or erroneous estimate in the estimation of the synchronization parameters such as Δ f, M (t) soft value of the despreading output of reality can be made to diminish, and can produce relatively macrorelief with channel variation.Even the factor such as (fall π), loop concussion causes despreading output soft value symbol upset because carrier phase 180 ° upset, error code after causing adjudicating.
According to the present embodiment, improving on the basis of transmitter spread spectrum mode, have also been changed the reception mode that conventional art is usual simultaneously, do not need any synchronization loop, and rely on despreading correlation energy total value to make decisions, recover primary signal.The following is detailed description of the invention:
It was noted that the complete expression of I, Q two-way despread signal M (t) described above, N (t), contain two orthogonal factors of cos and sin respectively, when carrier wave Complete Synchronization, after despreading, correlation energy concentrates on I road (in-phase branch)；When carrier wave is asynchronous, energy can to some extent " leakage " to Q road (quadrature branch).So, by squarer 309,310 and adder 311, seek the quadratic sum of M (t) and N (t), it is possible to obtain a correlation energy total value unrelated with carrier wave phase-frequency error:
Meanwhile, according to the dicode spread spectrum of the present embodiment offer, solid size despreading strategy, have:
Namely C is usedaSequence is simultaneously as I, Q two-way this locality despreading code word.
So now
Wherein RaK () is CaAuto-correlation function, due in a code word period, RaK it is unimodal to there is sharp-pointed auto-correlation in (), and Ra,b(k) absolute value bounded and much smaller than Ra(k) peak value, by normalization unit 312, the normalization correlation energy after can de-spreading:
Therefore, we set a normalization threshold value (such as 0.7), by threshold judgement unit 313, to E'(t in each code word period) make decisions, if there being correlation energy value to exceed thresholding, then this code word period is adjudicated as " 1 "；If all crossing thresholding without correlation in a code word period, then can adjudicate as " 0 ".Thus can correctly recover raw information s (t).
Second embodiment
Fig. 4 illustrates the communication system receiver structured flowchart of second embodiment of the invention.With reference to shown in Fig. 4, the receiver 400 of the present embodiment includes demodulating unit 401 and 403, local carrier generator 402, low pass filter 404 and 405, despread unit 406 and 408, local solution extended code generator 407, despread unit 409 and 410, adder 411 and threshold judgement unit 412.The transmitter of the present embodiment can be identical with the transmitter 200 of first embodiment.
On the basis of first embodiment, based on the consideration reducing circuit realiration cost, the receiver 400 of the present embodiment is when calculating correlation energy total value E (t), by asking absolute value element 409,410 and adder 411, with absolute value summation operation approximate substitution quadratic sum computing, it may be assumed that
OrderKnown It addition, have equally Therefore:
Meanwhile, for reducing implementation complexity further, save normalization unit, E (t) is not done normalization computing, and by arranging suitable soft value thresholding TH, threshold judgement unit 412 is made directly judgement.
In each code word period, if there being correlation energy value E (t) > TH, then this code word period is adjudicated as " 1 "；If all crossing thresholding without correlation in a code word period, then judgement is " 0 ".Thus can recover raw information s (t).
3rd embodiment
In actual applications, based on reducing circuit realiration complexity further and reducing the consideration of transmitter power consumption, it is proposed to the present embodiment.
Fig. 5 illustrates the communication system transmitter structured flowchart of third embodiment of the invention.With reference to shown in Fig. 5, transmitter 500 includes spectrum-spreading unit 501, spreading code generator 502, base band formed filter 503, modulating unit 504 and carrier generator 505.Spectrum-spreading unit 501, base band formed filter 503 and modulating unit 504 are sequentially connected with.Spreading code generator 502 connects spectrum-spreading unit 501, and carrier generator 505 connects modulating unit 504.
The present embodiment, on the basis of embodiment one or embodiment two, changes the spread spectrum strategy launching pusher side, for " 1 " in original binary information data s (t), still with CaSequence carries out spread spectrum as spread spectrum code word；And for information data " 0 ", with special full 0 sequence (Cb=0) as spread spectrum code word, it may be assumed that
So after transmitter spread spectrum multiplication operation, carrier modulation multiplication operation, in the period corresponding to input data " 0 ", radio frequency output data are full 0, namely do not launch any energy.Transmitter output signal is as follows:
Therefore, the number of number occurs, it is possible in the consumption reducing transmitting power in varying degrees with " 0 " in raw information s (t).
The receiver of the present embodiment can be identical with receiver 300 and 400 shown in first embodiment or the second embodiment.For receiver, there is C equallydess=Ca, the calculating receiving correlation energy total value E (t) is identical with first embodiment one or the second embodiment, is distinctive in that the R when s (t)=0a,b(k) correlation.Due to now Cb=0, transmitter does not have energy to send at s (t)=0 data segment, what therefore participate in despreading correlation computations after this period enters receiver down coversion, filters is the random noise being mixed on line, generally may be considered the white noise in Gauss distribution, and it de-spreads code word C with localaOrthogonal, and little in frequency acceptance band self-energy.Therefore Ra,b(k) calculated coherence spectra absolute value still bounded, and C during much smaller than s (t)=1aAutocorrelation spectrum peak value R (0).Meet two spread spectrum code words of the present invention and choose condition.
So, by with the identical decision method described in first embodiment or the second embodiment, according to pre-determined threshold, in a code word period, correlation energy E (t) is carried out threshold judgement, primary signal s (t) can be recovered.
Although the present invention discloses as above with preferred embodiment; so it is not limited to the present invention, any those skilled in the art, without departing from the spirit and scope of the present invention; when doing a little amendment and perfect, therefore protection scope of the present invention is when with being as the criterion that claims define.
Claims (12)
1. a spread spectrum modulation technique, including utilizing spreading code that raw information carries out the step of spread spectrum, and to the step that the data after spread spectrum are modulated, wherein said spreading step comprises the following steps:
Produce the sequence pair that autocorrelation is excellent and cross correlation is less；And
As spread spectrum code word, the first number of described raw information is carried out spread spectrum with the First ray of described sequence pair, as spread spectrum code word, the second number of described raw information is carried out spread spectrum by the second sequence of described sequence pair.
2. spread spectrum modulation technique as claimed in claim 1, it is characterised in that described sequence pair meets:
Autocorrelation spectrum in the described First ray cycle presents sharp-pointed single-peak response: absolute value=1, normalized autocorrelation peak and only occurring once, all the other secondary lobes absolute value < 0.2；
The coherence spectra bounded of two sequences, normalized crosscorrelation absolute value < 0.3.
3. spread spectrum modulation technique as claimed in claim 1, it is characterised in that described sequence pair is that the m-sequence produced by different primitive polynomials for a pair is preferably right.
4. spread spectrum modulation technique as claimed in claim 1, it is characterised in that described sequence pair be Gold sequence to or Golay complementary series pair.
5. spread spectrum modulation technique as claimed in claim 3, it is characterised in that described sequence preferably to the second sequence be full 0 sequence.
6. a despread-and-demodulation method, including the step being demodulated to received signal, demodulation signal is filtered producing the filter step of I, Q two-way baseband signal, and to the step that described I, Q two-way baseband signal de-spreads, wherein said spreading steps includes:
Produce this locality despreading code word, described local despreading code word is chosen from the First ray in the sequence pair that an autocorrelation is excellent and cross correlation is less, in raw information in wherein said reception signal, first number is that the First ray with described sequence pair carries out spread spectrum as spread spectrum code word, the second number be by the second sequence of described sequence pair as spread spectrum code word to carrying out spread spectrum；And
Respectively described I, Q two-way baseband signal is de-spread by described local despreading code word.
7. despread-and-demodulation method as claimed in claim 6, it is characterised in that the step respectively described I, Q two-way baseband signal de-spread by described local despreading code word includes:
Carry out I road related operation with described local despreading code word and I roadbed band signal, and carry out Q road related operation by described local despreading code word with Q roadbed band signal simultaneously；And
Described I road correlation result is carried out squared computing, obtains I road despread signal；Simultaneously to the squared computing of correlation result of described Q road, obtain Q road despread signal；
Described I road despread signal and described Q road despread signal are carried out addition and obtain correlation energy total value；And
Described correlation energy total value is normalized computing, obtains normalization correlation energy.
8. despread-and-demodulation method as claimed in claim 7, it is characterised in that the step respectively described I, Q two-way baseband signal de-spread by described local despreading code word also includes:
Described normalized energy is set a normalization threshold value make decisions；
In each code word period of described local despreading code word, when described normalization correlation energy value exceedes described normalization threshold value, adjudicate as described first digital；
When described normalization correlation energy value is lower than described normalization threshold value, adjudicate as described second digital.
9. despread-and-demodulation method as claimed in claim 6, it is characterised in that the step respectively described I, Q two-way baseband signal de-spread by described local despreading code word includes:
Carry out I road related operation with described local despreading code word and I roadbed band signal, and carry out Q road related operation by described local despreading code word with Q roadbed band signal simultaneously；
Described I road correlation result is asked signed magnitude arithmetic(al), obtains I road despread signal；Described Q road correlation result is asked signed magnitude arithmetic(al) simultaneously, obtain Q road despread signal；
Described I road despread signal and described Q road despread signal are carried out addition and obtain correlation energy total value.
10. despread-and-demodulation method as claimed in claim 9, it is characterised in that the step respectively described I, Q two-way baseband signal de-spread by described local despreading code word also includes:
Described correlation energy total value is set a threshold value make decisions；
In each code word period of described local despreading code word, when described correlation energy total value exceedes described threshold value, adjudicate as described first digital；And
When described correlation energy total value is lower than described threshold value, adjudicate as described second digital.
11. a band spectrum modulation device, including:
Spreading code generator, generates a pair autocorrelation excellent, and the less sequence pair of cross correlation is as spread spectrum code word；
Spectrum-spreading unit, receive the sequence pair that described spreading code generator generates, as spread spectrum code word, the first number of described raw information is carried out spread spectrum with the First ray of described sequence pair, as spread spectrum code word, the second number of described raw information is carried out spread spectrum by the second sequence of described sequence pair；
Base band formed filter, is shaped filtering to the signal after described spectrum-spreading unit spread spectrum；
Carrier generator, generates modulation Yong mono-tunnel carrier signal；And
Modulating unit, utilizes described sinusoidal carrier signal that the signal after described base band formed filter is modulated.
12. a despread-and-demodulation device, it is characterised in that including:
Local carrier generator, generates mutually orthogonal a pair carrier signal that solution is called；
Demodulating unit, utilizes the pair of mutually orthogonal carrier signal to be demodulated to received signal, output I, Q two-way demodulation signal；
Low pass filter, demodulates signal to described I, Q two-way and carries out low-pass filtering, export I, Q two-way baseband signal；
Local solution extended code generator, produce this locality despreading code word, described local despreading code word is chosen from the First ray in the sequence pair that an autocorrelation is excellent and cross correlation is less, in raw information in wherein said reception signal, first number is that the First ray with described sequence pair carries out spread spectrum as spread spectrum code word, the second number be by the second sequence of described sequence pair as spread spectrum code word to carrying out spread spectrum；And
Despread unit, receives the described local this locality despreading code word solving the generation of extended code generator, utilizes described local despreading code word respectively described I, Q two-way baseband signal to be de-spread.
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