CN106508101B - Hidden antijam communication transmitter and receiver - Google Patents
Hidden antijam communication transmitter and receiverInfo
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- CN106508101B CN106508101B CN200610119865.5A CN200610119865A CN106508101B CN 106508101 B CN106508101 B CN 106508101B CN 200610119865 A CN200610119865 A CN 200610119865A CN 106508101 B CN106508101 B CN 106508101B
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Abstract
The invention discloses a kind of hidden jam-resistant communication system, wherein, transmitter includes：Modulating unit, simulation upconverting unit and the power emitting unit being sequentially connected, is also included coding spread spectrum unit, is connected with modulating unit, there is provided coding spread spectrum signal；The coding spread spectrum unit enters modulating unit modulation after being added with the same step pseudo-code signal of tracking and the data road signal for sending for capture, or is added output again after two-way is respectively fed to modulating unit modulation.Of the invention have identical capacity of resisting disturbance with existing spread spectrum system, while reducing the transmission occupied bandwidth of spread spectrum signal, reduces the complexity of circuit realiration.
Description
Technical field
The present invention relates to a kind of transceiver communication system, more particularly to hidden jamproof communication transmitter and receiver.
Background technology
To prevent from being scouted and being disturbed by enemy in military communication, generally ensure the hidden anti-interference of communication link using spread spectrum technology
Transmission.Spread spectrum technology is a kind of information processing transmission technology.Spread spectrum technology is utilized with the unrelated code of data to be transmitted (information)
To being transmitted signal extension frequency spectrum, it is allowed to take considerably beyond the minimum bandwidth necessary to transmission information.Utilize in receivers
The same code docking collection of letters number synchronizes relevant treatment with despread-and-demodulation and recovers data.Conventional modulation system, such as amplitude modulation, tune
Frequency and pulse code modulation etc. also extend the frequency spectrum for being transmitted information, but they are all not belonging to spread spectrum technology.Wide-band LFM makes
Radio frequency bandwidth is very wide, or even also wider than the bandwidth of some spread spectrum systems, but wide-band LFM is mainly used in radar,
It spread spectrum technology is not attributed to.
Here the spread spectrum technology said has three below characteristic：
1. spread spectrum signal is uncertain pseudorandom broadband signal；
2. spread spectrum signal bandwidth is much larger than data to be transmitted (information) bandwidth；
3. there must be the copy with broadband carrier frequency synchronization in receiver.
Due to the above-mentioned characteristic of spread spectrum technology, spread spectrum system has the characteristics that：
1. due to the unpredictability of spread spectrum signal, spread spectrum system has very high antijamming capability.Because intruder is difficult to pass through
Observation improves its jamming performance, and can only use and the unmatched perturbation technique of disturbed signal.
2. the power of spread spectrum signal is quite evenly distributed on very wide frequency range, so that it is very low to be transmitted signal power density, detect
Receiver is examined to be difficult to detect.Therefore, spread spectrum system has low probability of intercept.
3. by the coherent detection to broadband spread spectrum signal, it can make spread spectrum system that there is very high range discrimination.Thus, expand
Spectrum signal is easily solved that operating distance is remote and the high contradiction of range discrimination, and can not obscure and test the speed, available for anti-multipath jamming.
4. spectrum-expanding communication system has good CDMA communication ability.
5. couple different user uses different codes, other people can not eavesdrop their communication, thus spread spectrum system has high secrecy
Property.
Spread spectrum technology research subject matter be performance metric, spread-spectrum codes design and performance, the lockon and follow of spread spectrum signal and
Interference rejection capability of spread spectrum system etc..Existing conventional spread spectrum system has following three class：
1. Direct sequence spectrum system
Direct sequence spread spectrum system abbreviation directly-enlarging system (DDS) is Resistant DS Spread Spectrum System (DS), or cries direct sequence system
System.Precisely, it is this to be referred to as the system with coded sequence to carrier modulation.Coded sequence in direct sequency system leads to
It is often pseudo-random sequence or is pseudo noise (PN) code.What is transmitted becomes binary digit sequence after information digitalization, it and it is pseudo-
After random sequence exclusive-OR modulation carrier wave is removed into compound key.Phase-shift keying (PSK) modulation generally is carried out to carrier wave in direct sequency system.
Balanced modulator is used in order to save transmission power and improve in transmitting operating efficiency, spread spectrum system.The balance modulation of suppressed carrier
Device is also favourable to the anti-reconnaissance capability for improving spread spectrum signal.Launched after spread spectrum signal is modulated using phase-shift keying (PSK) by antenna,
There is the synchronous local code of the pseudo noise code in one and emitter in receivers, signal be de-spread, the signal after despreading
It is sent to the information that demodulator takes out transmission.
The features such as Direct sequence spectrum system has hidden, anti-interference, anti-intercepting and capturing, anti-multipath and CDMA, the army of being widely used in
Thing communicates and commercial communication field, but the frequency-hopping spectrum-expanding system being described below to determining the strongly disturbing antijamming capability of frequency to be not so good as.
2. frequency-hopping spectrum-expanding system
Frequency hopping spread spectrum system abbreviation frequency-hopping spectrum-expanding system (FHS), more specifically should be called " multifrequency, code choosing, frequency displacement key
Control " system.Simple frequency shift keying generally only utilizes two frequencies.And frequency hopped systems usually have thousands of or even tens thousand of
Individual frequency is alternative, is determined from which frequency by code.
Frequency hopped systems are mainly made up of code generator and frequency synthesizer two parts.The frequency synthesizer of quick response is frequency
The critical component of jump system.The emitter of frequency hopped systems is in a predetermined frequency set by code sequence control frequency synthesis
Device makes tranmitting frequency randomly jump to another by one.Frequency synthesizer also saltus step in the same order in receiver, is produced
The local frequency of one and tranmitting frequency an only poor intermediate frequency, obtains a fixed intermediate-freuqncy signal after mixed.This intermediate frequency is believed
It is number amplified to be sent to the information that demodulator takes out transmission.
Frequency-hopping spectrum-expanding system has anti-frequency decline, hides the features such as interference and easily composition communication network, is widely used in electromagnetism
In the complicated GSM of environment, but there is the problem of signal is disguised poor, the mode of avoidance can only be taken interference signal.
Expand mixing spread spectrum system 3. jumping
The higher application scenario of processing gain is being required, a kind of spectrum extending method presented hereinbefore is used alone and can be potentially encountered technology
Difficulty in realization, at this moment can be received using the direct-sequence spread spectrum system of frequency hopping one (FH/DS is referred to as jumped and expanded mixing spread spectrum system)
Preferable effect.
Jumping expansion mixing spread spectrum system has the advantages that Direct sequence spectrum system and frequency-hopping spectrum-expanding system, while utilizing Direct sequence spectrum system
Disguise makes up the deficiency of frequency-hopping spectrum-expanding system with certain anti-point frequency interference performance, and interference is hidden by frequency-hopping spectrum-expanding system
Feature, to overcome Direct sequence spectrum system to be afraid of the fixed strongly disturbing problem of frequency.Jump and expand mixing spread spectrum system due to the advantage of itself,
Used by satellite communication link.
The subject matter that above-mentioned three kinds of spread spectrum systems are present is：While antijamming capability is improved, the bandwidth of signal transmission
Greatly increase, increased multiple is from tens times to thousands of times.CDMA up-link is saved frequency band using multi-system spread spectrum and accounted for
With, but there are problems that synchronization acquistion time length, need feedback information and circuit realiration, be not suitable for military antijam communication
System.
The content of the invention
Therefore the technical problems to be solved by the invention, which are to provide a kind of and existing spread spectrum system, has identical antijamming capability, same
When reduce spread spectrum signal transmission occupied bandwidth and reduction circuit realiration complexity hidden jam-resistant communication system, the system can
Save existing frequency resource.
What the present invention was specifically realized in：
A kind of hidden antijam communication emitter, including：Modulating unit, simulation upconverting unit and the power emission being sequentially connected
Unit, also including coding spread spectrum unit, being connected with modulating unit, there is provided coding spread spectrum signal；The coding spread spectrum unit will be used
Into modulating unit modulation, or two after capturing with the same step pseudo-code signal of tracking and being added for the data road signal of transmission
Road is added output again after being respectively fed to modulating unit modulation.
By such scheme, data to be sent are weaved into 2NGroup code, with pseudo noise code PN logical multiplications, is changed into compound key, each
Moment is used as address to gate specific 2 by the data-signal of N-bitNAccordingly exporting all the way in group code, is used as data road to believe
Number；By by locally generated with described 2NGroup code coded system and code length identical synchronizing signal are patrolled with identical pseudo noise code PN
Collect and be multiplied, be changed into compound key, be used as same step pseudo-code signal；Wherein, N is for integer and equal to or more than 4.
By such scheme, described 2NGroup code uses mutually orthogonal walsh code characters or gold code characters or m-sequence group.
By such scheme, when described 2NWhen the code length of group code is equal to or more than 128, type B error random code PN length and 2NGroup code
Code length it is identical, be combined after length it is constant, one symbol of length representative of a compound key.
By such scheme, when described 2NWhen the code length of group code is less than 128, type B error random code PN length is 2NThe code length of group code
Integral multiple, the length that the length after being combined is pseudo noise code PN, the length of a compound key can transmit the integer symbol
Data.
A kind of hidden antijam communication receiver, including：The radiofrequency signal receiving unit that is sequentially connected, analog down unit,
AD conversion unit, Digital Down Convert unit, it is also single including same step acquiring pseudo code and tracking cell and the despreading of data road and demodulation
Member；The signal point two-way come from Digital Down Convert unit, send same step acquiring pseudo code to synchronize signal with tracking cell all the way
Capture and tracking, the despreading and demodulation that the despreading of data road with demodulating unit receive data are sent in another road；With step acquiring pseudo code
With tracking cell synchronizing signal is provided for the despreading of data road with demodulating unit.
By such scheme, the capture of synchronizing signal is using matching correlation method：In each sampling, sent by Digital Down Convert unit
Signal carries out related operation in matched filter with local pseudo-code input signal, its output through thresholding relatively after most
The synchronizing signal that big value obtains for acquisition success.
By such scheme, the despreading of data road includes 2 with demodulating unitNThe parallel correlator accumulator in road, a maximum comparator and
One decoder；The synchronizing signal captured with step acquiring pseudo code and tracking cell is supplied to the despreading of data road and demodulating unit conduct
The cumulative output pulse of the cumulative reset signal of correlator accumulator and a upper PN-code capture；There is one per correlator accumulator all the way locally
Pseudo-code input signal, when the signal that Digital Down Convert unit is sent is identical with the pseudo-code input signal on this road, road correlation is tired
Plus device can export a big correlation peak signal, 2NThe output of road correlator accumulator is compared in maximum comparator simultaneously,
The decoding that the output on a maximum road send decoder to carry out N-bit is taken out, decoder is output as the data flow that despread-and-demodulation goes out；
Wherein, 2NTo send the group number of data.
By such scheme, correlator accumulator includes accumulator, latch, quadratic sum circuit and threshold compataror；Accumulator is one
There is the adder of symbol, the signal that adder is sent to digital down-converter unit carries out accumulation and added deduct, the step-length of accumulation is pseudo-code
The half period of chip, the symbol end control added deduct by accumulator, the input at symbol end is controlled by local pseudo-code input signal；
When the signal that Digital Down Convert unit is sent is identical with the pseudo-code input signal on the road, accumulator is output as positive or negative phase
Peak value is closed, the accumulated value of a upper PN-code capture is squeezed into latch by the peak value before accumulator clearing by synchronizing signal, subsequent
Quadratic sum circuit is uniformly changed into accumulated value positive value, is easy to Threshold detection below；When threshold compataror detects the road square
When the value of sum is more than a certain value, show the possibility for there are relevant peaks, the value is directly to maximum comparator；Such as value of the road quadratic sum
No more than a certain value when, show the possibility very little of relevant peaks, to the road assign a very little value, be then sent through maximum and compare
Device.
By such scheme, the input at accumulator symbol end is by local pseudo-code input signal control：Pseudo-code input signal is logic
Add when 1, subtract when being logical zero；Or pseudo-code input signal be logical zero when add, subtract when being logic 1.
As a result of said apparatus, the present invention compared with prior art, with advantages below：
The present invention, using multi-system thought, makes the occupancy of frequency band be reduced to original 1/4 while hidden antijam communication is provided
Hereinafter, it compensate for deficiency of the existing spread spectrum system in Military Application.
The present invention is compared with Direct sequence spectrum system, removed by the application of coding spread spectrum technology (alternatively referred to as encoding spread spectrum technology)
Outside with its due hidden noiseproof feature, it is ensured that the frequency band for saving more than 4 times takes, and is adapted to what is be limited in band resource
In the case of, improve antijamming capability or improve message transmission rate.Due to the flexibility of coding spread spectrum system design, by same
The different utilizations of step, can be applicable in the systems such as military burst transfers of data, high dynamic data transfer and ranging localization.
Threshold compataror is employed in the present invention in the realization of data despread-and-demodulation and maximum comparator two-stage compares, it is to avoid one
The erroneous judgement of level, improves the reliability of data receiver, reduces the bit error rate for receiving data.
After the completion of the present invention is developed, we enter in terms of emulation and practical application two with the Direct sequence spectrum system of same spread gain
The comparison of following performance is gone：
1. anti-interference, anti-intercepting and capturing performance
Anti-interference, anti-intercepting and capturing performance is mainly embodied by spreading gain.By emulation and actual test, spread spectrum of the invention increases
Benefit is more slightly lower than Direct sequence spectrum gain, but within 0.5dB.
2. anti-multipath performance
Tested by instrument simulation, both are without any difference.
3. performance is caught soon
Theoretical calculation and actual test all indifferences.
4. frequency band is saved
The multiple that frequency band is saved is relevant with code efficiency, but is limited by data rate and frequency band transmission resource, and code efficiency is too high
System, which is realized, afterwards becomes complicated.System, most short spread-spectrum pseudo code length are encoded with saving the pass of multiple by frequency band after coding spread spectrum
It is as shown in the table：
| Encode system | Frequency band saves multiple | Most short spread-spectrum pseudo code length |
| 4-16 is encoded | 4 times | 32 |
| 5-32 is encoded | 5 times | 64 |
| 6-64 is encoded | 6 times | 128 |
| 7-128 is encoded | 7 times | 256 |
| 8-256 is encoded | 8 times | 512 |
The efficiency of coding system presentation code in table, such as " 4-16 codings " represents that the data of 4 bits are represented with 16 groups of codes,
The length of 32 expressions pseudo-code used in colleague.In direct sequence spread spectrum, if the length of spreading code is 32, represent that 1 compares
Special data are replaced with the pseudo-code of 32, and transmission bandwidth is 32 times before spread spectrum.After 4-16 coding spread spectrums, digit is spread
Kept for 32, be only 8 times before spread spectrum because 32 pseudo-codes represent transmission bandwidth after the data of 4 bits, spread spectrum, make transmission
Frequency band save 4 times.
Brief description of the drawings
Fig. 1 for coding spread spectrum QPSK modulation in I, Q two paths of signals signal format；
Fig. 2 is the theory diagram of hidden jam-resistant communication system；
Fig. 3 is the generation of hidden jam-resistant communication system emission part demal and realizes block diagram；
Fig. 4 be hidden jam-resistant communication system receiving portion pseudo-code tracing and data demodulate realize block diagram；
Fig. 5 realizes block diagram for hidden jam-resistant communication system receiving portion despread-and-demodulation；
Fig. 6 is the compound schematic diagram in embodiment one with step or data road yard；
Fig. 7 is the compound schematic diagram in embodiment two with step or data road yard.
Embodiment
The specific implementation process of the present invention is further described below in conjunction with accompanying drawing：
First, the present invention is main saves spectral bandwidth by the application of coding spread spectrum technology, first below to the reality of coding spread spectrum technology
Existing principle is explained.
Coding spread spectrum technology employs the thought of multi-system spread spectrum, the information of N-bit with one group mutually orthogonal 2NGroup code is carried out
Represent, this 2NGroup code can be mutually orthogonal walsh code characters, gold code characters or m-sequence group.Walsh code characters are completely just
The code character of friendship, can just meet 2NThe requirement of length, as each membership synchronization in code character, cross-correlation function is zero, orthogonal
Property very well, but autocorrelation is bad, it is impossible to is captured and is tracked as synchronous code, so individually by 2NGroup walsh codes can not
Constitute actual system；The length of gold code characters and m-sequence group is 2N- 1, afterbody when actually used in code adds one 1,
Making the length of code turns into 2NPosition, but be quasiorthogonal code between each code of such code character, cross correlation value is smaller but is not zero, auto-correlation
Function preferably, can complete the capture and tracking of code as synchronous code, if directly using needs 2NGroup matching correlator is completed
The capture and tracking of code, can also so do during only several groups codes, and when N is more than 2, capture can refer to the resource shared by tracking
Several times increase, and algorithm also becomes complicated, constitutes a practical system difficult.
The coding spread spectrum technology used in the present invention overcomes the difficulty in above-mentioned realization.Now illustrated by taking walsh code characters as an example.
If every 4 bit is a symbol, theoretical by multi-system needs 16 group (24Group) mutually orthogonal walsh codes, the length of code
When taking 32 (minimum length required in coding spread spectrum technology), there are 32 mutually orthogonal codes, use wjTo represent a code,
J is 0 to 31 integer, and table real code number chooses 16 codes that j is 1 to 16 when realizing.Any chip of any one yard
It is expressed as wjn, n is 0 to 31 integer, then the cross-correlation of any two yards is represented by：
Formula (1) is the correlation properties of walsh codes.It can be seen that from formula (1), when only the same signal of two-way is related,
Just there is related big value, available for solution data output.Walsh codes and the pseudo noise code used below are all 2 system numbers, used
Multiplying is logical multiplication.
To solve capture and the tracking problem of coding spread spectrum system, w0As same step (also referred to as with phase road, abbreviation I roads),
wj(j is 1 to 16), as data road (also referred to as positive cross-channel, abbreviation Q roads), this two-way is multiplied by same 32 (gold respectively
Code or m-sequence add a pseudo noise code PN 1), then I roads signal is changed into PN × w0Compound key, Q roads signal is changed into PN × wj
Compound key, I roads signal is referred to as and road signal after being added with Q roads signal.With PN × wj(j is 0 to 16 integer) conduct
Local code goes with I, Q road and road signal to carry out related operation, and when locally synchronous with the signal on I, Q road, correlation output is：
The result in formula (1) has been used in formula (2).It can be seen that from formula (2), do not influence the solution on data road with step
Number.
When locally asynchronous with the signal on I, Q road, correlation output is：
Formula (3) has used the correlation properties of pseudo noise code, illustrate data road do not influence the capture of the pseudo noise code of same step with
Track characteristic.With reference to formula (2) and formula (3), using coding spread spectrum technology, the data solution under multi-system spread spectrum system can be achieved
The capture and tracking of mediation code.
2nd, based on above-mentioned principle, coding spread spectrum system is described further by following three aspects.
1. system uses requirement of the direct sequence spread spectrum to transmission bandwidth
Assuming that the data rate to be transmitted is 1Mbps, using the direct sequence spread spectrum of 32 pseudo-codes, then the bit rate after spreading is：
rc=32 × 1Mbps=32MHz (4)
After being modulated using BPSK, a width of 64MHz of band that signal main lobe takes, the limit band for carrying out 80% is also required to 50MHz's
Transmission bandwidth.So big transmission bandwidth, very big difficulty is all brought to circuit realiration and frequency allocation.Using coding spread spectrum skill
It is postoperative, band resource occupancy can be solved well greatly and technology realizes the problem of difficulty is big, it is easily real under existing technical conditions
It is existing.
2. system uses requirement of the coding spread spectrum to transmission bandwidth
The basic thought of coding spread spectrum is that before spread spectrum data are carried out with coding reduction of speed processing.The data of N-bit are compiled when realizing
(limited for a symbolic unit in view of code efficiency by data rate, frequency band transmission resource and system complexity, N number
Value scope is generally 4~8, and 4 are let n equal here and is easy to description, is not intended to limit the invention), the data of this 4 bit are hinted obliquely at
For 16 symbols, w is set to1, w2... w16, each symbol replaces with a spread-spectrum pseudo code, and this 16 groups of pseudo-codes are mutually orthogonal.
Spread spectrum code check after reduction of speed is handled is：
r′c=32 × 256kbps=8MHz (5)
Wherein, 256Kbps is the character rate after 1Mbps data rate reductions of speed.After being modulated using BPSK, signal main lobe is accounted for
13MHz transmission bandwidth is only needed to after a width of 16MHz of band, the limit band for carrying out 80%.Such transmission bandwidth is using existing
Spread spectrum telemetering channel can be transmitted, but despreading processing can not with simple direct sequence spread spectrum processing method.Because the biography of data
It is defeated be it is random, that transmitted in each moment channel is one in 16 groups of orthogonal pseudo-codes, despreading receiver can not possibly be simultaneously
This 16 groups codes are captured and tracked, it is necessary to there are new means to solve the capture and tracking of coding spread spectrum signal with method.
3. acquiring pseudo code and the realization of tracking in coding spread spectrum
To solve to modulate using QPSK in the capture of pseudo-code and tracking problem, scheme in coding spread spectrum.The I roads of modulation be for
The synchronous pseudo-code signal with tracking is captured, Q roads are coding spread spectrum signal.The signal format of I, Q two paths of signals is as shown in Figure 1.
It can be seen from figure 1 that I roads spread-spectrum pseudo code is 128 (mending " 1 " behind 127 gold codes), a synchronous PN-code capture is included
The data symbol pseudo-code of 4 32.Modulated signal is after such specially treated, and when despreading is with demodulation, I roads can be used
The method of direct sequence spread spectrum carries out the capture and tracking of pseudo-code.After the completion of code tracking, the parallel correlator accumulator in 16 tunnels is passed through on Q roads,
The demodulation of 16 symbols is carried out, is finally 4 demodulated data streams the symbol substitution of demodulation.It is another after the modulation scheme
Maximum benefit is that I roads spreading gain is big, improves the probability of success of system acquisition and the precision of pseudo-code tracing.
After the processing of encoded spread spectrum and I, Q two-way modulated signal, the reduction of speed and spread spectrum of data are not only realized, letter is also allowed for
Number capture and tracking.But the transmission time of pictorial data is short, it is desirable to which receiver is rapidly completed the capture and tracking of signal.Using
After coding spread spectrum technology, every 4 bit represents the symbol pseudo-code for including 4 Q roads in a symbol, the PN-code capture on each I roads,
The data of 16 bits are then included in the PN-code capture on each I roads.In capture, if using half-chip as an acquisition phase,
Then the pseudo-code of 128 needs 256 phase slips.Using the conventional sequential correlation technique of direct sequence spread spectrum, then needed for once capturing
Maximum number bits be：
256 × 16=4096 (bits)
Time equivalent to 4.096ms, to ensure reliable capture, capture time takes 10 times of the time, i.e. 40.96ms.Root
The characteristics of according to practical application, it is necessary to using the fast Capture Technique of pseudo-code, it is ensured that catching for pseudo-code is completed within several milliseconds of time
Obtain.
To complete fast Acquisition when realizing, commonly use matched filter correlation method and replace sequential correlation technique.The work of matched filter
Principle is that when its input signal is a buckles, it can actually produce an output signal, and the signal is wave filter
The reversion of the input signal of desired detection in time, that is to say, that the transfer function of matched filter is wanted matched signal
Complex conjugate.When signal is embedded in Gaussian noise, matched filter makes its output signal-to-noise ratio maximum.
From the point of view of the characteristic of matched filter, after PN synchronization capture is upper, matched filter is output as maximum, compares through thresholding
After provide acquisition success instruction.In Digital Realization scheme, matched filter is to carry out a related operation in each sampling,
When sample rate is 2 times of pseudo- bit rate, required capture time is 1/the 128 of sequential detection, it is ensured that system is 1ms's
The capture of signal is completed in time.The acquisition speed of this catching method is fast, reduces the time just caught and caught again, is adapted to burst and passes
Defeated application field.
3rd, it is of the invention to implement：
It is as shown in Figure 2 using the hidden jam-resistant communication system of coding spread spectrum technology.The system includes emitting portion and receiving portion,
Dotted line is above is emitting portion, dotted line is the following is receiving portion.Emitting portion completes to send the spread spectrums of data, modulation, in simulation
Frequency conversion and power emission, the reception of receiving portion completion radiofrequency signal, analog down, analog-to-digital conversion, Digital Down Convert, number
According to despreading and demodulation.What dotted line left side presentation code was spread realizes part, includes the spreading part spreads and despread-and-demodulation of coding spread spectrum
Part, the right represents the other parts of system support.
The generation of emission part demal of the present invention is as shown in Figure 3 with realizing.With step signal by w0Obtain same with PN codes logical multiplication
The compound key of step, data route wjThe compound key on data road is obtained with PN codes logical multiplication, it is assumed here that it is one to take 4 bits
Group is encoded, then j takes 1 to 16 integer, and data road each moment expresses this 4 bit by one of 16 groups of compound keys
Number, is that this 16 groups of numbers are put into storage stack when implementing, is used as address by the data-signal of 4 bits to gate tool
Accordingly exporting all the way in 16 groups of codes of body.With step with data road signal be added after enter modulation, can also two-way respectively to one
To being added output after quadrature carrier modulation again, the latter is conducive to the permanent carrier-wave transmission of aerial waveform.
In emitting portion, the generation of code belongs to the innovative point of the present invention, its principle and implements and is above making detailed retouch
State, other realizations use the ordinary skill in the art, be not described in detail herein.
The realization of pseudo-code tracing and the data demodulation of receiving portion of the present invention is as shown in Figure 4.Intermediate-freuqncy signal after being digitized through A/D
Digital Down Convert is first passed through, intermediate-freuqncy signal is changed into the baseband signal of zero intermediate frequency.Baseband signal point two-way, leads up to same step
Signal completes the capture and tracking of code, and the despread-and-demodulation for data road provides synchronizing signal.Another road goes to 16 tunnels on data road related
Accumulator, after the information of reception is mutually shut with any road in 16 tunnels, the road is output as a maximum, and is exported with other roads
Compared to obvious difference.The signal all the way of maximum is exported after decoding, the data message of transmission can be recovered.
The reception down coversion part of receiving portion of the present invention, A/D conversion portions, Digital Down Convert part are embodied as routine techniques,
With the capture of step and the capture realized with existing spread-spectrum pseudo code of track algorithm as the realization of track algorithm, routine is fallen within
Technology.With matching correlation technique to realize fast Acquisition, is employed in the capture of step pseudo-code, match the realization of correlator with it is straight
Realizing in sequence spread spectrum system is identical, falls within routine techniques.The realization of the despreading and demodulation on coding spread spectrum receiving portion data road
Creative for the present invention is realized, below to now particularly being solved in fact.
Fig. 5 is that the despread-and-demodulation that coding spread spectrum is received realizes block diagram.The signal come from Digital Down Convert, send same step to carry out all the way
Send the despreading and demodulation that data road carries out data-signal in the synchronization and tracking of synchronous pseudo-code, another road.Catching for pseudo-code is completed with step
After obtaining, into pseudo-code tracking mode when the output one and synchronization pulse of PN synchronization, the signal is supplied to the conduct of data road
The cumulative output pulse of the cumulative reset signal of data road correlator accumulator and a upper PN-code capture.Data road has 16 tunnels correlation cumulative
Device, per there is a local pseudo-code input signal all the way, when the input signal after down coversion is identical with the pseudo-code signal on this road,
The road correlator accumulator can export a big correlation peak signal.The output of 16 road correlator accumulators is compared in a maximum simultaneously
It is compared in device, the output for taking out a maximum road carries out the decoding of 4 bits, and decoding is output as the data flow solved.
The correlator accumulator of the present invention includes accumulator, latch, quadratic sum circuit and threshold compataror.Accumulator has symbol for one
Number adder, adder carries out accumulation to the signal that is inputted after down coversion and adds deduct, and the step-length of accumulation is half of pseudo-code chip
Cycle, the symbol end control added deduct by accumulator, the input at symbol end is controlled by local pseudo-code, when defining pseudo-code for logic 1
Plus, subtract when being logical zero, when input signal and the road signal code-phase simultaneously, accumulator is output as positive or negative relevant peaks
The accumulated value of a upper PN-code capture is squeezed into latch by value, the peak value before accumulator clearing by synchronizing signal, subsequent square
Accumulated value is uniformly changed into positive value with circuit, is easy to Threshold detection below.When threshold compataror detects this road quadratic sum
When value is more than a certain value, show the possibility for there are relevant peaks, the value is directly to maximum comparator；Value such as this road quadratic sum is little
When a certain value, show the possibility very little of relevant peaks, the value of a very little is assigned to the road, maximum comparator is then sent through.
Two embodiments are set forth below to be further described implementing for the present invention：
The present invention is according to pseudo noise code and the difference of walsh code lengths, and it is realized there is certain difference, embodiment is divided below
One and embodiment two illustrate.
Embodiment one：When the code spread for multi-system data is longer, when typically taking more than or equal to 128, using embodiment one
Implementation, the difference of implementation be mainly reflected in two-way code it is compound on.In the implementation complex method of code with Fig. 6 come
Represent, the length of pseudo noise code is as the length of walsh codes in figure, and the length after being combined is constant, the length of a compound key
Represent a symbol.Because data spreading code is longer when this mode is realized, walsh codes can be replaced with pseudo noise code, this
When original compound key be changed into only pseudo noise code.Each pseudo-code of recipient can solve the information of a symbol.
Embodiment two：When the code spread for multi-system data is shorter, when typically taking less than 128, using the reality of embodiment two
Existing mode, the difference of implementation is mainly reflected in being combined for two-way code.The complex method of code is represented with Fig. 7 in the implementation,
The length of pseudo noise code is 4 times (or other integral multiples) of walsh code lengths in figure, and the length after being combined is the length of pseudo-code
Degree, the length of a compound key can transmit the data of 4 symbols.Because data spreading code is shorter when this mode is realized, to protect
Demonstrate,prove orthogonality good, general to use walsh codes, at this moment compound key is pseudo noise code and the logic multiply of 4 groups of walsh codes.Recipient
Each pseudo-code can solve the information of 4 symbols, if encoded using 4-16, each bit of symbology 4, then a puppet
The code cycle can transmit the data of 16 bits.
Embodiment enumerated above is only typical application, can not limit the interest field of the present invention with this certainly, therefore according to
The equivalent variations that scope of the present invention patent is made, still belong to the scope that the present invention is covered.
Claims (3)
1. a kind of hidden antijam communication receiver, including：The radiofrequency signal receiving unit that is sequentially connected, analog down unit,
AD conversion unit, Digital Down Convert unit, it is characterised in that also including same step acquiring pseudo code and tracking cell and data road
Despreading and demodulating unit；
The signal point two-way come from Digital Down Convert unit, send same step acquiring pseudo code to synchronize signal with tracking cell all the way
Capture and tracking, the despreading and demodulation that the despreading of data road with demodulating unit receive data are sent in another road；With step acquiring pseudo code
With tracking cell synchronizing signal is provided for the despreading of data road with demodulating unit；
Data road is de-spread includes 2 with demodulating unitNThe parallel correlator accumulator in road, a maximum comparator and a decoder；
The synchronizing signal captured with step acquiring pseudo code and tracking cell is supplied to the despreading of data road with demodulating unit as correlator accumulator
The cumulative output pulse of cumulative reset signal and a upper PN-code capture；There is a local pseudo-code input letter per correlator accumulator all the way
Number, when the signal that Digital Down Convert unit is sent is identical with the pseudo-code input signal on this road, the road correlator accumulator can export one
Individual big correlation peak signal, 2NThe output of road correlator accumulator is compared in maximum comparator simultaneously, takes out a maximum
The decoding that decoder carries out N-bit is sent in the output on value road, and decoder is output as the data flow that despread-and-demodulation goes out；
Wherein, 2NTo send the group number of data；
Correlator accumulator includes accumulator, latch, quadratic sum circuit and threshold compataror；Accumulator is an addition for having symbol
Device, the signal that adder is sent to digital down-converter unit carries out accumulation and added deduct, and the step-length of accumulation is half week of pseudo-code chip
Phase, the symbol end control added deduct by accumulator, the input at symbol end is controlled by local pseudo-code input signal；When change under numeral
When the signal that frequency unit is sent is identical with the pseudo-code input signal on the road, accumulator is output as positive or negative correlation peak, should
The accumulated value of a upper PN-code capture is squeezed into latch, subsequent quadratic sum circuit by peak value before accumulator clearing by synchronizing signal
Accumulated value is uniformly changed into positive value, is easy to Threshold detection below；When threshold compataror detects that the value of the road quadratic sum is more than
During a certain value, show the possibility for there are relevant peaks, the value is directly to maximum comparator；The value of such as road quadratic sum is no more than a certain
During value, show the possibility very little of relevant peaks, the value of a very little is assigned to the road, maximum comparator is then sent through.
2. hidden antijam communication receiver as claimed in claim 1, it is characterised in that
The capture of synchronizing signal is using matching correlation method：In each sampling, the signal sent by Digital Down Convert unit with it is local
Pseudo-code input signal a related operation is carried out in matched filter, its export through thresholding relatively after maximum to be captured as
The synchronizing signal that work(is obtained.
3. hidden antijam communication receiver as claimed in claim 1, it is characterised in that
The input at accumulator symbol end is controlled by local pseudo-code input signal：Pseudo-code input signal adds when being logic 1, to patrol
Subtract when collecting 0；Or pseudo-code input signal be logical zero when add, subtract when being logic 1.
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|---|---|---|---|
| CN200610119865.5A CN106508101B (en) | 2006-09-21 | 2006-09-21 | Hidden antijam communication transmitter and receiver |
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| CN200610119865.5A CN106508101B (en) | 2006-09-21 | 2006-09-21 | Hidden antijam communication transmitter and receiver |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115189715A (en) * | 2021-04-02 | 2022-10-14 | 湖南工商大学 | Optical transmission device and method based on direct spread spectrum time division multiplexing |
| CN116667880A (en) * | 2023-07-26 | 2023-08-29 | 天津七一二通信广播股份有限公司 | Network domain cooperative interference detection and intelligent frequency hopping anti-interference method and system |
-
2006
- 2006-09-21 CN CN200610119865.5A patent/CN106508101B/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115189715A (en) * | 2021-04-02 | 2022-10-14 | 湖南工商大学 | Optical transmission device and method based on direct spread spectrum time division multiplexing |
| CN116667880A (en) * | 2023-07-26 | 2023-08-29 | 天津七一二通信广播股份有限公司 | Network domain cooperative interference detection and intelligent frequency hopping anti-interference method and system |
| CN116667880B (en) * | 2023-07-26 | 2023-11-10 | 天津七一二通信广播股份有限公司 | Network domain cooperative interference detection and intelligent frequency hopping anti-interference method and system |
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