CN108667484A - Incoherent spread spectrum digital transceiver instantaneous frequency measurement and demodulation method - Google Patents
Incoherent spread spectrum digital transceiver instantaneous frequency measurement and demodulation method Download PDFInfo
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/69—Spread spectrum techniques
- H04B1/707—Spread spectrum techniques using direct sequence modulation
- H04B1/7073—Synchronisation aspects
- H04B1/7075—Synchronisation aspects with code phase acquisition
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/69—Spread spectrum techniques
- H04B1/707—Spread spectrum techniques using direct sequence modulation
- H04B1/7073—Synchronisation aspects
- H04B1/7085—Synchronisation aspects using a code tracking loop, e.g. a delay-locked loop
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/69—Spread spectrum techniques
- H04B1/707—Spread spectrum techniques using direct sequence modulation
- H04B1/7073—Synchronisation aspects
- H04B1/7087—Carrier synchronisation aspects
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/69—Spread spectrum techniques
- H04B1/707—Spread spectrum techniques using direct sequence modulation
- H04B1/7097—Interference-related aspects
- H04B1/71—Interference-related aspects the interference being narrowband interference
- H04B1/7101—Interference-related aspects the interference being narrowband interference with estimation filters
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/69—Spread spectrum techniques
- H04B1/707—Spread spectrum techniques using direct sequence modulation
- H04B1/7097—Interference-related aspects
- H04B1/711—Interference-related aspects the interference being multi-path interference
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/0014—Carrier regulation
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/26—Systems using multi-frequency codes
- H04L27/2601—Multicarrier modulation systems
- H04L27/2647—Arrangements specific to the receiver only
- H04L27/2655—Synchronisation arrangements
- H04L27/2657—Carrier synchronisation
- H04L27/2659—Coarse or integer frequency offset determination and synchronisation
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/32—Carrier systems characterised by combinations of two or more of the types covered by groups H04L27/02, H04L27/10, H04L27/18 or H04L27/26
- H04L27/34—Amplitude- and phase-modulated carrier systems, e.g. quadrature-amplitude modulated carrier systems
- H04L27/38—Demodulator circuits; Receiver circuits
- H04L27/3845—Demodulator circuits; Receiver circuits using non - coherent demodulation, i.e. not using a phase synchronous carrier
- H04L27/3854—Demodulator circuits; Receiver circuits using non - coherent demodulation, i.e. not using a phase synchronous carrier using a non - coherent carrier, including systems with baseband correction for phase or frequency offset
- H04L27/3872—Compensation for phase rotation in the demodulated signal
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/0014—Carrier regulation
- H04L2027/0024—Carrier regulation at the receiver end
- H04L2027/0026—Correction of carrier offset
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/0014—Carrier regulation
- H04L2027/0044—Control loops for carrier regulation
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- Synchronisation In Digital Transmission Systems (AREA)
Abstract
A kind of incoherent Spread Spectrum Digital transceiver instantaneous frequency measurement and demodulation method disclosed by the invention, it is desirable to provide a kind of algorithm implementation complexity is low, the instantaneous frequency measurement and demodulation method of anti-multistation interference, the technical scheme is that：Incoherent reception algoritic module captures Doppler frequency and code phase, and the sampled data of analog-digital converter is detected by synchronous head, completes synchronous head coherent detection；Instantaneous frequency measurement module, which is measured and compensated near real-time ms magnitude Doppler frequency differences with Digital Down Converter Module, eliminates Doppler, pass through IDF filtering extraction device filtering extractions and matched filtering, sign bit is directly taken to I, Q data, become single-bit subsequent processing, completes non-coherent demodulation, RS decoding output user data；Spread spectrum transmission algoritic module send DAC digital-to-analogue conversions, DAC to turn single-end transformer by both-end, output instantaneous frequency measurement and demodulated signal is filtered through second filter by carrying out symbol mapping, modulation after framing, RS codings, differential encoding and Direct Sequence Spread Spectrum processing.
Description
Technical field
Present invention is mainly applied to the formation of inexpensive short-distance wireless or cluster observing and controlling or low speed number to pass field, be 10km or less
Short-distance wireless fleet system provide interference between a kind of low cost, anti-multinode, small in volume Spread Spectrum Digital transceiver.
Technical background
Any digital communication system is all the transmission of discrete signal, it is desirable that transmitting-receiving two-end signal is identical in frequency and phase
It is upper consistent, it could correctly demodulate information.Spread spectrum communication system is no exception.One relevant spread-spectrum digital communication system, connects
Receiving end must realize that synchronous information code element, PN codes symbol and sequence synchronization and radio carrier frequency synchronize with transmitting terminal.Only realize
These are synchronized, and floating enlarging system could normally work.It may be said that not synchronous just do not have spread spectrum communication system.Can be that spread spectrum is logical
Letter is very important technology in current information field, since spread spectrum communication has very strong anti-interference letter, good confidentiality
And the features such as low in energy consumption, so it becomes a kind of communication technology being widely used.Sequence spread spectrum code sequence is that a kind of comparison is normal
With pseudo-random sequence, why it can obtain the attention of height in spread spectrum communication, be because it has relatively good auto-correlation
Property, it is that pseudo noise sequence in the narrow sense, and small sequence is easy to generate and replicate.Scrambling, encryption in numerical data, mistake
Sequence is also commonly used in the various fields such as symbol measure and the CDMA of synchronization and satellite communication.Due to some of pseudo noise code
Relevant characteristic makes pseudo-random sequence come through the frequency spectrum frequently as the spread spectrum in spread spectrum communication system.And the speed in these characteristics
The important indicators such as degree, length, type of coding directly affect the performance of spread spectrum communication system.In the sequence of symhols of random signal
It is likely to occur waveform and continuously occurs same waveform within very long a period of time.This can cause receiving terminal that cannot will be apparent that
Recognize the terminal of symbol.
Carrier synchronization in any one communication system, all can't do without send and received signal.In actual application
In the process, the useful signal sended over is exactly extracted from the signal received.Because of the meeting in the transmission process of signal
The factors such as noise, interference are encountered to be distorted.These factors will influence the parameters such as the amplitude of signal itself, phase and frequency.
So-called synchronization is exactly that can preferably restore original signal just to may require that the process for carrying out these signals parameter estimation.In reality
Synchronization includes carrier synchronization, code synchronization and bit synchronization etc. in commonly used communication system.Wherein carrier synchronization plays non-wherein
Often important position.There are mainly two types of the methods of carrier synchronization.It is inserted into pilot tone system.The method is exactly the signal sent in transmitter
The middle synchronization for being inserted into a special wave.Pilot tone is typically the sinusoidal signal without ovennodulation of single or multiple specific frequencies.
Then it proposes pilot signal in receiving terminal, the locally generated load of receiver is determined using the phase and frequency of this pilot signal
The phase and frequency of wave signal.This method is usually in the transmission process of signal and signal using more.Direct method be exactly
Receiver end directly extracts carrier signal from the useful signal received, comes without special in first method
Transmit pilot signal.This method can also be called self-synchronizing method.Direct method has the signal of carrying information during transmission
The characteristics of possessing whole transmission powers.The prior art proposes that the method for carrier wave is to use usually in the signal that receiving terminal receives
Frequency multiplication divides method.But in frequency dividing, there are phase indeterminacies.Also, there is also unstability in channel, make to receive
The phase of signal generates random fluctuation, if the carrier wave of receiving terminal cannot track variation with it, will result in same phase
It is reverse.Receiver not can determine that the initial position for receiving spreading code in signal in general, this is because transceiver
Caused by the factors such as both sides' clock is unstable, signal propagation delay, frequency expansion sequence startability difference.In order to solve the problems,
So needing a yard synchronization system in receiver system.
The first step of code synchronization system is exactly Code acquisition, and Code acquisition is exactly to make the code in receiver and the code in reception signal
Phase alignment, Code acquisition are also known as thick synchronous.Next it is code tracking, the effect of code tracking is exactly to allow the local code of receiver
It is further reduced with error on the signal phase that receives.One important characteristic of pseudo-random sequence is its auto-correlation letter
Several main peak values is very big, and the capture and tracking of frequency expansion sequence are realized according to this characteristic.It is main in digital transceiver
The link wanted is PN synchronization, and two committed steps in code simultaneous techniques are Code acquisition and code tracking.Point based on correlator
Duan Xiangguan seeks the serial acquisition method of absolute value sum；Track the method using delay lock loop.In actual application, code
Synchronizing process is more complicated, and there are many kinds of the synchronous method of code.If considering from the signal domain received, big portion
Divide main study still over the frequency domain.And for opposite time domain, the signal received is handled from frequency domain to be made
Reach synchronous there is quite high anti-interference and multipath effect, and can more solve those since sending and receiving end frequency is different, more
Problem caused by general Le effect.The process of PN synchronization is namely consistent the pseudo-code at digital transceiver both ends,
During this PN synchronization mainly include two parts, one be pseudo-code capture, the other is pseudo-code with Code acquisition
Stage, so that the pseudo noise code of the generation of digital receiver is differed in phase with the pseudo noise code received and be less than some valve
Value, this threshold values set in actual application process are smaller than the minimum chip width of half of pseudo noise code.In its capture
Method on it is most of be all to use serial acquisition, parallel capture, serial parallel capture, multichannel correlation capturing and matched filter
Method etc., at present there is no special new technologies.
The research to pseudo-code tracing domestic at present is mainly to the selection of loop bandwidth and the design of loop parameter, to change
The performance of PN code tracking loop.The country also has many experts to want to realize acquiring pseudo code using technologies such as wavelet transformation, nerve nets
New way, but currently the majority is merely resting on the stage of research, without much practical applications.Just enter after the completion of capture
Tracking phase makes the pseudorandom phase that digital receiver generates closer to the phase of the pseudo noise code of digital transmitter,
It is exactly the phase for the pseudo-code that digital receiver receives.The tracking of pseudo-code is also known as essence and synchronizes, and transmitting-receiving in general can be made after code tracking
The symbol error of both-end can control in 1/10th symbol.Code tracking is typically all the track side using delay lock loop
Method.The method of delay lock loop is very effective in the phase difference for tracking two signals, this is because auto-correlation function has
Diadic characteristic, such delay lock loop can be to them into line trace.So all being utilized in most of communication system this
Method carries out pseudo-code tracing.Transceiver uses Digital Signal Processing, is realized with adaptive-filtering.The transmitting-receiving run at present
Letter machine substantially use amplitude keying formula can internal loopback transceiver, using noncoherent detection (15 "+) mode, i.e.,
Envelope detection.It is realized simply, but noise robustness is undesirable.Receiver can use the phase that coherent demodulator and integrator form
Device is closed to realize, condition, which is the filter after coherent demodulation, to be designed in strict accordance with the requirement of matched filtering, could be realized true
Positive optimum reception.The relevant detection of signal can make the energy resonance of information enhance, greatly improve signal-to-noise ratio, still
It needs to generate local with frequently with phase carrier wave.Meanwhile in order to realize optimum reception, sharp filter is also realized, to inhibit noise
Energy improves signal-to-noise ratio.If the local carrier with frequency with phase with signal carrier cannot be generated, would be possible to after coherent demodulation
Bring serious distortion；Meanwhile the filter Design of Passive Power Filter of high q-factor is extremely complex, technological level requirement is very high, it is difficult to
Ensure performance, and time delay is very big, this is also exactly current transceiver rare the reason of using coherent demodulation.
Home and abroad document discloses the spread spectrum transceiver for much using irrelevant method, and disclosed scheme is usually more
Be mostly to use complicated code using related spread spectrum receiver method and synchronize ring scheme, receiver is still more complicated,
FPGA resource consumption is relatively more；Its algorithm structure includes three big loop of code ring, carrier wave ring and bit synchronization ring, and design is complicated most
Height is not suitable for low at design use.There is no the scheme of instantaneous frequency measurement compensation using the present invention.Resistant DS Spread Spectrum System can be met
To various interference, removes outside multi-path jamming, common are broadband interference and (throat sound usually is from, such as thunder and lightning, atmospheric noise, industry
Equipment igniter etc.).Demodulation calculates the detection structure for being followed by preamble detecting, differential ference spiral pair using irrelevant cross product and dot product
Carrier wave frequency deviation is insensitive, but carrier wave frequency deviation is excessive or carrier wave frequency deviation produces phase, caused decision problem in the data that are added to.
In synchronous transmission network, each data station is assigned in a series of time slots, and each website can only be in the time slot of oneself
Middle transmission data, and other website cannot send information in this time slot.So some empty time slots are just had
It is not utilized, causes the waste in resource.
Invention content
The purpose of the present invention is for the big deficiency of the of high cost of the prior art, algorithm complexity, provide it is a kind of it is small,
Light weight and cost is low, algorithm implementation complexity is low, the incoherent Spread Spectrum Digital transceiver instantaneous frequency measurement and solution of anti-multistation interference
Tune method, to solve the problems, such as that wireless short-range remote control sum number passes instantaneous frequency measurement and demodulation.
The above-mentioned purpose of the present invention can be reached by the following measures, and a kind of incoherent Spread Spectrum Digital transceiver is instantaneous
Frequency measurement and demodulation method have following technical characteristic：Incoherent reception algoritic module built in on-site programmable gate array FPGA and
Spread spectrum transmission algoritic module, plug-in a piece of BPI configuration chips and Clock management chip CLK and Clock management chip CLK pass through
Analog-digital converter ADC connected cmos memory CMOS, analog-digital converter ADC turn both-end by single-ended
Transformer is connected first filter；FPGA output ends plug-in digital analog converter DAC, digital analog converter DAC turn single-ended by both-end
Transformer is connected second filter；External clock in single ended input is divided into three tunnels by Clock management chip CLK, and first via clock passes through
First CMOS supplies FPGA, and the second road clock is supplied to analog-digital converter ADC to be used as and adopts by the 2nd CMOS outputs 40MHz frequencies
Sample clock, third road clock export Low Voltage Differential Signal LVDS and supply FPGA fan-out mode converters DAC as sampling clock；
Incoherent reception algoritic module is received through the first single-ended the first filtering for turning both-end transformer down coversion and being sent into analog-digital converter ADC
Device be filtered after filtering signal, capture Doppler frequency and code phase, frame be followed by using irrelevant cross product and dot product calculating
Head detection, synchronous head detect the sampled data of analog-digital converter ADC, complete related；In FPGA, analog-digital converter ADC samplings
Data carry out ms magnitudes instantaneous frequency measurement through Digital Down Convert, instantaneous frequency measurement unit module and update cycle, near real-time ms magnitudes are more
Doppler is eliminated in general Le frequency difference compensation, direct to I, Q data after IDF filtering extraction device filtering extractions and matched filtering
Sign bit is taken, becomes single-bit and carries out subsequent processing, RS decodings is then completed, user is exported after non-coherent demodulation, RS decodings
Data；Spread spectrum transmission algoritic module receives user data, is handled by framing, RS codings, differential encoding and Direct Sequence Spread Spectrum
Symbol mapping, modulation are carried out later, digital analog converter DAC is sent to carry out digital-to-analogue conversion, and digital analog converter DAC turns single-ended by both-end
Transformer filters output instantaneous frequency measurement and demodulated signal through second filter.
The present invention has the advantages that compared with the prior art.
It is small, light weight and cost is low.The present invention uses incoherent reception algorithm built in on-site programmable gate array FPGA
Module and spread spectrum transmission algoritic module, plug-in a piece of BPI configuration chips and Clock management chip CLK and Clock management chip
The analog-digital converter ADC that CLK is connected by cmos memory CMOS, analog-digital converter ADC pass through list
End turns the connected first filter of both-end transformer；The plug-in digital analog converter DAC of FPGA output ends, digital analog converter DAC passes through double
End turns the connected second filter of single-end transformer.Using low cost, the FPGA of low-power consumption and its attached chip, FPGA, which is used, to be had
The Xilinx-XC65SLX100 chips of 1000000 gate logic resources, cost of hardware design is low, and entire pcb board size is 65mm*
35mm, weight 20g, power consumption are less than 4W, meet entire design requirement.System cost, volume, weight and power consumption can be made to reduce, firmly
Part designs and digital algorithm is using low cost and low-complexity implementing method, and the soft and hardware method of use is from communication system angle
Optimize cost and implementation complexity, meets the requirement of system, volume at low cost compared to complicated coherent reception implementation
Small, light-weight, small power consumption.Using frequency instantaneously adjustable digital down converter, instantaneous frequency measurement Doppler effect correction.Incoherent solution
It adjusts, export user data after RS decodings.It is that follow-up related and preamble detecting all greatly simplifies due to only taking symbol to signal, directly
The method for picking up sign bit can remove the AGC modules of prime needs from, also greatly simplify the subsequent arithmetic processing of system, such as
Multiplication becomes addition and subtraction etc..
Algorithm implementation complexity is low.The present invention uses incoherent reception algoritic module built in on-site programmable gate array FPGA
Doppler frequency and phase acquisition are realized with spread spectrum transmission algoritic module, and the frame synchronization in conjunction with dot product cross product data result is fuzzy
Detection, enhances the robustness of detection；Demodulation is followed by preamble detecting using irrelevant cross product and dot product calculating, using instantaneous frequency measurement
The unit module ms magnitude update cycles, using the incoherent spread spectrum receiver algorithm of open loop, in combination with a variety of letters normal in engineering
Change JPL and simplify algorithm, and is related using a variety of simplified algorithms such as similar accumulators, further decrease computing resource consumption and
FPGA power consumptions.Complicated spreading code ring, carrier wave ring, bit synchronization ring scheduling algorithm structure are not used, are encoded using RS (15,11), is poor
Coded, spread spectrum code length 32~512, BPSK modulation systems, direct open loop receive, and optimize, are not necessarily to from communication sending and receiving link
It designs code complicated in correlation receiver scheme and synchronizes ring, carrier synchronization ring, bit synchronization ring, reduce algorithm complexity, reduce
FPGA resource consumption.In conjunction with subsequent noncoherent detection, dot product cross product non-coherent demodulation can tolerate the frequency deviation of 2kHz, preceding
Face Doppler frequency compensation pressure is little, and instantaneous frequency measurement can meet, and without complicated loop, further decreases the resource of algorithm
The complexity of consumption and entire reception scheme；The IDF methods that output is reset using accumulator and periodically substitute traditional FIR filters
Correlator is become accumulator by wave device, reduces resource consumption, and JPL simplifies algorithm and realizes that plural modulus substitutes using adder-subtractor
The multiplier resources of script, to I, Q data directly carry out hard decision, simplify the complexity of follow-up despreading correlation computations.It adopts
With the method for frame head fuzzy detection, i.e., by the negated later data of the data and the two of the dot product of data and cross product all into
Row preamble detecting detects that the data frame of frame head is output as correct frame and receives and export, and avoids necessary complicated carrier wave phase
Position parameter estimation algorithm.
Anti- multistation interference.The present invention opens electricity before crystal oscillator and other factors cause frequency drift to be stablized for system, just fast
Speed enter working condition application characteristic, incoherent reception algoritic module receive through first it is single-ended turn both-end transformer down coversion,
First filter be filtered after analog-digital converter ADC sampled data, related, synchronous head detection and non-is completed in FPGA
Correlation demodulation.The non-coherent approaches of use are all detected judgement to cross product and dot product, and not having other method phaselocked loops can not
It locks or because of the problems such as impacting losing lock.Spread spectrum transmission algoritic module direct sequence spread spectrum has very high processing gain, can be to useful
Signal carries out correlation reception, spouts row spread spectrum to interference signal, and most of power of interference can be received machine intermediate frequency band logical
Filter filters out, so the anti-dry anti-performance of system is very strong.
Algorithm implementation complexity is small.The present invention uses two-stage frequency measurement scheme (bigness scale and accurate measurement), with millisecond ms magnitudes
The frequency compensation update cycle, it disclosure satisfy that engineering requirements；Instantaneous frequency measurement Doppler Compensation Method of the present invention, point
The irrelevant demodulation method of product-cross product, synchronous head inspecting method and data frame head inspecting method, make the digital algorithm of receiving terminal,
It no longer needs complicated carrier synchronization ring, bit synchronization ring and PN synchronization ring, therefore incoherent is connect than traditional in terms of complexity
Receiving algorithm and coherent reception algorithm has apparent advantage.
The present invention uses integrate-dump IDF filtering extractions device, sign bit is taken to adjudicate direct hard decision, JPL simplification algorithm, letter
Simple correlation etc. reduces computing resource consumption；This is because when signal cross over-sampling multiple it is very high when integrate-dump IDF filters, no
As traditional FIR filter is realized using multiply-accumulator resource, but is realized using accumulator, adjacent sampled point is added up
Together, it is completed at the same time the function of filter and extraction, after the points for the requirement that added up, integrator (accumulator) is reset, into
Row is accumulated next time, therefore resource consumption is smaller；It is to do hard decision to the fixed-point data of multidigit width (such as 10) to take symbol, defeated
Go out to obtain 0,1bit streams, the various calculating of bit streams are all simplified, saves FPGA resource consumption；JPL, which will simplify algorithm, to be answered
Miscellaneous plural modulus, is reduced to add operation, saves FPGA resource consumption；The later correlation of hard decision is on bit flowing water
It carries out, no longer using multi-position fixed point multiplier, but the simply bit arithmetics such as and-or inverter, simplify operation.
Description of the drawings
It for a clearer understanding of the present invention, now will through the embodiment of the present invention, referring concurrently to attached drawing, to describe this hair
It is bright, wherein：
Fig. 1 is the incoherent Spread Spectrum Digital transceiver instantaneous frequency measurement of the present invention and demodulation hardware circuit composition frame chart.
Fig. 2 is the circuit diagram of the incoherent reception algoritic module and spread spectrum transmission algoritic module in Fig. 1.
Fig. 3 is the instantaneous frequency measurement module principle block diagram in Fig. 2.
Fig. 4 is the schematic diagram that frequency-code phase two dimension that frequency divides slot to search in Fig. 3 divides slot to search for.
Fig. 5 is non-coherent demodulation module principle block diagram in Fig. 2.
Specific implementation mode
Refering to fig. 1.In the embodiment described below, incoherent Spread Spectrum Digital transceiver instantaneous frequency measurement and demodulation method
The hardware circuit of incoherent the Spread Spectrum Digital transceiver instantaneous frequency measurement and demodulation that use, including, it is embedded on pcb board at the scene
Program the open loop type incoherent reception algoritic module and spread spectrum transmission algoritic module in gate array FPGA chip.Field programmable gate
The peripheries array FPGA mounting Clock management chip, filtering chip, electrical level transferring chip, BPI configuration chips and interface card,
Receiving signal digitalization and transmitting signal analog-digital converter ADC and digital analog converter DAC respectively.The plug-in a piece of BPI configurations of FPGA
Chip and Clock management chip CLK and Clock management chip CLK pass through cmos memory CMOS phases
Analog-digital converter ADC even, wherein incoherent reception algoritic module input terminal is single-ended by analog-digital converter ADC connected first
Turn both-end transformer and first filter, analog-digital converter ADC turns the connected first filter of both-end transformer by single-ended；FPGA
Output end plug-in digital analog converter DAC, digital analog converter DAC turn the connected second filter of single-end transformer by both-end；Clock
External clock in single ended input is divided into three tunnels by managing chip CLK, and first via clock supplies FPGA by the first CMOS, when the second tunnel
Clock exports 40MHz frequencies by the 2nd CMOS and analog-digital converter ADC is supplied to be used as sampling clock, and third road clock exports low pressure
Differential signal LVDS supplies FPGA fan-out mode converters DAC as sampling clock；Incoherent reception algoritic module receives warp
First it is single-ended turn both-end transformer down coversion be sent into analog-digital converter ADC first filter be filtered after filtering signal,
Doppler frequency and code phase are captured, preamble detecting is followed by using irrelevant cross product and dot product calculating, synchronous head detects modulus and turns
The sampled data of parallel operation ADC is completed related；In FPGA, analog-digital converter ADC sampled datas are through Digital Down Convert, instantaneous survey
Frequency unit module carries out ms magnitudes instantaneous frequency measurement and update cycle, and Doppler is eliminated in the compensation of near real-time ms magnitude Doppler frequency differences,
After IDF filtering extraction device filtering extractions and matched filtering, sign bit is directly taken to I, Q data, becomes single-bit progress
Subsequent processing then completes RS decodings, user data is exported after non-coherent demodulation, RS decodings；Spread spectrum transmission algoritic module connects
User data is received, by carrying out symbol mapping, modulation after framing, RS codings, differential encoding and Direct Sequence Spread Spectrum processing, is sent
Digital analog converter DAC carries out digital-to-analogue conversion, and digital analog converter DAC turns single-end transformer by both-end, filtered through second filter
Export instantaneous frequency measurement and demodulated signal.
FPGA is the core algorithm chip of digital transceiver algorithm, and Xilinx company models may be used and be
The fpga chip of XC6SLX100-2FG484I, the fpga core chip voltage are 1.2V, and I/O voltages are 3.3V, logical resource
It is 1,000,000.The plug-in a piece of BPI of FPGA configure chip, may be used and support BPI patterns, model S29GL256P10TFI010
32MB.
Analog-digital converter ADC chips may be used resolution ratio be 14bit, sampling rate 80Msps, model TI companies
ADS6142 chips.Resolution ratio 14bit, sample rate 1Gsps, model ADI company AD9957 may be used in digital analog converter DAC
Chip.
Model LFCN-80 chips may be used in filter.Clock chip uses the AD9513 of ADI, clock input range
For 0~1.6GHz, the output of AD9513 clocks includes 3 road LVDS or 6 road CMOS, and wherein LVDS maximum outputs frequency is 800MHz,
CMOS maximum output frequencies are 250MHz.Interior external clock realizes switching, the input of AD9513 clocks by changing ac coupling capacitor
End uses single ended input, 1 road CMOS (40MHz) of output to be supplied to ADC chips, and as sampling clock, LVDS outputs all the way supply
DAC sampling clocks are given, CMOS supplies FPGA all the way.
Single-ended 1 for turning both-end transformer and Mini-Circuit companies may be used:1 level conversion transformer (TC1-1T+).
Single ended signal is converted to differential signal and is sent to ADC chips or on the contrary DAC by level conversion transformer
Output difference signal is converted into single-ended analog signal output.
Refering to Fig. 2.Since the same frequency multistation spread spectrum system that the present embodiment uses is non-correlation reception, according to actual measurement Doppler
Frequency deviation does not influence subsequent demodulation processing within 2MHz, thus it is of less demanding to the frequency-measurement accuracy of instantaneous frequency measurement module, but to surveying
The real-time of frequency has the requirement of the frequency measurement update cycle of ms magnitudes, and instantaneous frequency measurement module, which must use, inhibits the signal at other stations dry
It disturbs, single the case where using of standing, instantaneous frequency measurement scheme can also be further simplified searching algorithm；This implementation real system link channel
Condition is preferable, using instantaneous frequency measurement method, disclosure satisfy that non-coherent demodulation and the relevant requirement of pseudo-code, therefore do not have in receiving algorithm
The loops such as the carrier synchronization ring, spread and disposal plus loop, the sign synchronization ring that have design complicated reduce the complexity of system realization
Degree.Spread spectrum transmission algoritic module built in FPGA and incoherent reception algoritic module.
Spread spectrum transmission algoritic module includes：Data framing module, RS coding modules, differential encoding module, direct sequence expand
The modules such as frequency module, symbol mapping block, modulation module and shaping filter, data framing module realize user's bit streams by fixation
Frame length forms physical layer transmission frame, and adds and synchronized and the frame synchronization head of acquisition of information, frame information field for receiving terminal；
RS coding modules use the IPcore in FPGA to realize that the RS of RS (15,11) format is encoded；Differential encoding module is public using coding
Formula：Realize differential encoding, that is, the coding at k moment exports input Ins of the Out (k) by the k moment
(k) exclusive or with the coding at k-1 moment output Out (k-1) obtains；Direct Sequence Spread Spectrum module is according to the PN codes of user setting
Number, it selects corresponding pseudo-code as spreading code from pseudo-code sequence module, the user data bit streams of input is spread；Expand
Data bit streams after frequency realize the symbol mapping of biphase phase shift keying BPSK modulation, i.e., bit symbols 0 are mapped to -1 constellation point,
Bit symbols 1 are mapped to+1 constellation point；The carrier wave that modulation module generates the number of constellation points evidence of input and carrier wave generation module
Cos is multiplied, and obtains modulation output；Filtering is formed in the form factor of modulated signal as required by shaping filter module, with drop
Low intersymbol interference improves frequency efficiency and improves out of band spectrum roll-off characteristic；The later data of forming filter are sent to DAC
Carry out digital-to-analogue conversion.
Incoherent reception algoritic module includes mainly：Digital Down Convert in sequential series, matched filtering, takes filtering extraction
The modules such as symbol, related, the irrelevant demodulation RS decodings detected with synchronous head, and it is connected in parallel on Digital Down Converter Module and filter
Instantaneous frequency measurement module between wave extraction and controlled local oscillator module.Digital Down Converter Module is controlled using controlled local oscillator module frequency
Local oscillation signal, Digital Down Convert is carried out to the digital signal that is inputted from ADC, to eliminate the frequency of the carrier doppler in input signal
Partially；If carrier doppler could not be eliminated complete, but remaining residual frequency deviation centainly, instantaneous frequency measurement by Digital Down Converter Module
Module will detect that this residual frequency deviation, residual frequency deviation can be applied to controlled local oscillator module control output local frequency value, pass through
The closed-loop control of this loop, to make to inhibit smaller numerical value from the carrier wave frequency deviation residual volume in ADC input signals；Filtering is taken out
Modulus block realizes low-pass filtering, and by higher input data sample rate (namely ADC sample rates), is reduced to and meets bandwidth and want
It asks and conducive in the rate that low-speed clock is realized in FPGA；Matched filtering module filtering form factor and transmitting terminal at
Shape filtering matches, and the later data of matched filtering are further extracted on reduction of speed to modulation symbol rate；Take symbol module pair
Incoming symbol, which directly takes, to be met, that is, hard decision, and positive fixed-point data is judged as 0, and negative fixed-point data is judged as 1,
Therefore the output data of symbol module is bit flow datas；Correlation module carries out the bit flow datas of input using local pseudo-code
Phase shift relevant search synchronous head reaches information, reaches once searching synchronous head, data are just sent to irrelevant demodulation module solution
It adjusts, otherwise loses data, continue search (burst communication mode) in real time；Irrelevant demodulation module is translated using cross product-dot product difference
Code mode decodes, and detects user data frame head behind, obtains correct data frame and is output to RS decoding modules；RS decodes mould
Block is also to use the IPcore in FPGA into row decoding, and coding formats are identical with coded format.
Refering to Fig. 3.In instantaneous frequency measurement module, due to there is 64 spread spectrum systems to work simultaneously with frequency, instantaneous frequency measurement module
Directly FFT cannot be used to carry out frequency measurement, because it is easy to measure the Doppler frequency at other stations and generate mistake, the present invention adopts
The two-dimensional search method that slot and pseudo-code phase divide slot, frequency dimension is divided to divide slot that can eliminate the frequency in advance and divide where slot with frequency
Frequency deviation, local pseudo-code phase divide slot to be different delays (phase) version of this pseudo-code, and when two-dimensional search will constantly adjust frequency
Divide slot and local code phase that slot is divided to scan for, only when the Doppler frequency of input signal and spread spectrum code phase fall into two dimension and search
When the frequency set when rope divides slot and local pseudo-code to divide slot, can just make subsequent correlator integrator, obtain higher relevant peaks and
It detects；In search, if frequency slots are incorrect, elimination divides slot frequency, and there are frequency differences can lead to correlator integrated value very little later
Without by thresholding, if spreading code (signals at other stations) is differed with local code in signal, the pseudo-code at difference station is uncorrelated, integral
Also very little can not be by thresholding for the output of device, if spreading code is the spreading code of our station in signal, but phase (delay) is different, mutually
Correlation integral value also can not be by thresholding, and the frequency only in signal and local divides slot, pseudo-code, pseudo-code phase three all to correspond to
After, integrator just has very high relevant peaks output.The present invention is to improve frequency-measurement accuracy, and level-one has also been cascaded after two-dimensional search
FFT accurate measurement frequencies.
Specific implementation method is：The data that incoherent reception algoritic module exports Digital Down Converter Module are sent into instantaneous
Frequency measurement mould integrate-dump filter IDF in the block be filtered extraction realize it is down-sampled, down-sampled later data pass through phase demodulation
Device module recovery goes out the Doppler frequency signal in signal, the possible maximum frequency range of carrier doppler is subdivided into multiple
Point slot or segmentation, using the centre frequency of frequency slots as Doppler shift, the frequency that is separated in maximum possible frequency range
In slot, parallel search is carried out using multiple search modules；When being searched in a frequency slots, it is also necessary to carry out pseudo-code phase movement
Search realizes the two-dimensional search instantaneous frequency measurement of Doppler and code phase, is divided slot frequency to disappear the current Doppler searched
Except frequency deviation；After dividing slot frequency to eliminate Doppler shift, mobile local code phase carries out all possible phase shift phase correlation and searches
Rope, correlated results are compared with given thresholding, determine whether search succeeds, and are searched for successfully, are otherwise used same by thresholding
Quadrat method has searched for all frequency slots, by correlated results by the code phase values of frequency slots thresholding be used as Doppler shift and
Code phase deviation, for the reliability of search process in practical realization, by all phase shift phases of all frequency slots and pseudo-code
All into search, retain the frequency and pseudo-code phase of the frequency slots at the corresponding place of maximum correlation peak, the survey as last search
Frequency result；Selecting module is exported by the data corresponding to the maximum peak frequency slots and code phase that search, is sent to FFT accurate measurement frequency moulds
Block carry out accurate measurement frequency, using discrete fourier transform FFT fast algorithm carry out complex transform, fast Fourier transform FFT transform with
Afterwards, it needs to carry out spectra calculation, needs to carry out modulus calculating using multiplier, in order to save resource, simplify and calculate, modulus is adopted
Simplify algorithm, calculation formula with JPL：
In formula, plural z=x+yi, i are imaginary unit's symbols, and x, y are real numbers.
The instantaneous frequency measurement value of the final output of instantaneous frequency measurement module be point slot frequency with accurate measurement frequency and, this and value are data
In carrier doppler frequency deviation, it is sent to controlled local oscillator module and generates corresponding quadrature carrier signals, with Digital Down Convert mould
The input signal mixing of block just eliminates carrier doppler.
The function of phase discriminator module is to eliminate the influence of modulation data information, recovers Doppler's frequency in suppressed carrier
Rate, due to being that modulating mode is modulated using BPSK, plural phase demodulation formula is as follows：
In formula, Ire、QimFor plural phase demodulation output signal, I, Q are the input signal of phase discriminator, and Δ ω is carrier doppler angular frequency
Rate,It is carrier wave first phase.
Refering to Fig. 4.To meet the instantaneous frequency measurement requirement of real-time of ms magnitudes, the present embodiment instantaneous frequency measurement module is using parallel
16 search modules divide slot frequency to scan for code phase simultaneously, realize that bigness scale frequency is worth；In bigness scale frequency, instantaneous frequency measurement module
Searcher since frequency-code phase divides the centre frequency f0 of slot frequency, carry out parallel search outward to positive and negative both direction；
Searcher first eliminates the Doppler divided where slot when searching for some frequency slots, then ties up sliding correlation intergal, phase in code phase
It closes integral and one integrated value is exported to each code phase, when integrated value is more than design threshold value, at this time in corresponding frequency slots
Frequency of heart is bigness scale frequency value, and corresponding code phase is the thick phase of code.
It is determined that frequency is divided after slot, divides the formula that slot frequency is eliminated as follows, eliminate I, Q the output number for dividing slot frequency later
According to,
In formula, I (t), Q (t) are the output valve of t moment phase discriminator, that is, the input value of frequency search, and Δ ω is a point slot frequency
With the frequency deviation of centre frequency f0,It is the difference during point slot frequency is eliminated.
The present embodiment has chosen the spreading code that 64 PN codes that autocorrelation haracter is good, cross correlation is very poor are stood as 64,
Spreading code a length of 32~512, spreading code is stored in RAM, often inputs the data of 1bit, is read according to spreading code number corresponding
The spreading code of length, when input data is 0, spreading code is negated as output, directly defeated without negating when input data is 1
Go out.
Due to receiver no longer using complicated code ring, carrier wave ring and bit synchronization ring come reduce Receiver Complexity and
Frequency-measurement accuracy is wanted to instantaneous frequency measurement update cycle demand in ms magnitudes by index decomposition in cost, non-coherent demodulation part
It asks in 2MHz or so, this method on the time and meets system requirements when searching for degree of parallelism n=16 in precision.
Refering to Fig. 5.In order to avoid there is small probability more than situation pi/2 and that data bit is fuzzy, frame head mould is used
The method for pasting detection, avoids mistake, i.e., all carries out the negated later data of the data and the two of the dot product of data and cross product
Preamble detecting detects that the data frame of frame head is output as correct data frame and receives and export.
Irrelevant differential decoding demodulation is realized by differential decoding, can eliminate the phase ambiguity of symbol, and
It is to Doppler nor very sensitive.In dot product-cross product non-coherent Differential decoding, the two of negated later I, Q two-way bit stream
Circuit-switched data is sent to dot product and cross product module completes cross product and dot product differential decoding, dot product, cross product result are sent to preamble detecting mould
Block later bit stream negated to the bit stream and the two of cross product, dot product carries out preamble detecting, using the frame head detected as just
Exact figures are according to frame difference output data.The formula of above-mentioned differential decoding is：
Dot product：Dot (k)=I (k-1) * I (k)+Q (k-1) * Q (k)
Cross product：Cross (k)=I (k-1) * Q (k)-Q (k-1) * I (k)
In formula, dot (k) indicates that the output of k moment dot products, cross (k) indicate that the output of k moment cross products, I (k), Q (k) indicate k respectively
The data bit of moment I, Q；
Carrier phase and initial value are eliminated after dot product and cross product operation, but carrier wave frequency deviation produces phase, is added to
In data, lead to decision problem.WhenCorrect data output is in dot product branch when less than pi/2；WhenIt is correct when more than pi/2
Data export in cross product branch；Phase value caused by frequency deviation is：
Wherein, Δ f is frequency deviation value, TbIt is the intervals bit；This programme carries out Data Detection to the output of cross product and dot product, ensures
Data frame is properly received ability, also reduces frequency-measurement accuracy requirement and the requirement of real-time of instantaneous frequency measurement module.
Above-described is only the preferred embodiment of the present invention.It should be pointed out that coming for those of ordinary skill in the art
It says, without departing from the principle of the present invention, several modifications and improvements can also be made, these alterations and modifications should be regarded as belonging to
In protection scope of the present invention.
Claims (10)
1. a kind of incoherent Spread Spectrum Digital transceiver instantaneous frequency measurement and demodulation method have following technical characteristic：Scene can compile
Incoherent reception algoritic module built in journey gate array FPGA and spread spectrum transmission algoritic module, plug-in a piece of BPI configuration chip and when
The modulus that clock managing chip CLK and Clock management chip CLK is connected by cmos memory CMOS
Converter ADC, analog-digital converter ADC turn the connected first filter of both-end transformer by single-ended；The plug-in digital-to-analogue of FPGA output ends
Converter DAC, digital analog converter DAC turn the connected second filter of single-end transformer by both-end；Clock management chip CLK will be single
External clock is divided into three tunnels in the input of end, and first via clock supplies FPGA by the first CMOS, and the second road clock passes through the 2nd CMOS
Output 40MHz frequencies are supplied to analog-digital converter ADC as sampling clock, and third road clock exports Low Voltage Differential Signal LVDS and supplies
To FPGA fan-out mode converters DAC as sampling clock；Incoherent reception algoritic module is received single-ended turns both-end through first
Transformer down coversion, be sent into analog-digital converter ADC first filter be filtered after filtering signal, capture Doppler frequency
And code phase, it is calculated using irrelevant cross product and dot product, is followed by preamble detecting, synchronous head detection, the sampling of analog-digital converter ADC
Data are completed related；In FPGA, analog-digital converter ADC sampled datas are carried out through Digital Down Convert, instantaneous frequency measurement unit module
Ms magnitudes instantaneous frequency measurement and update cycle, the compensation of near real-time ms magnitude Doppler frequency differences eliminate Doppler, pass through IDF filtering extractions
After device filtering extraction and matched filtering, sign bit is directly taken to I, Q data, becomes single-bit and carries out subsequent processing, it is then complete
It is decoded at non-coherent demodulation, RS, user data is exported after RS decodings；Spread spectrum transmission algoritic module receives user data, passes through
Carry out symbol mapping, modulation after framing, RS codings, differential encoding and Direct Sequence Spread Spectrum processing, send digital analog converter DAC into
Row digital-to-analogue conversion, digital analog converter DAC turn single-end transformer by both-end, and output instantaneous frequency measurement and solution are filtered through second filter
Adjust signal.
2. incoherent Spread Spectrum Digital transceiver instantaneous frequency measurement as described in claim 1 and demodulation method, it is characterised in that：It is non-
The hardware circuit that relevant Spread Spectrum Digital transceiver instantaneous frequency measurement is used with demodulation method, including, it is embedded on pcb board at the scene
Program the open loop type incoherent reception algoritic module and spread spectrum transmission algoritic module in gate array FPGA chip.
3. incoherent Spread Spectrum Digital transceiver instantaneous frequency measurement as claimed in claim 2 and demodulation method, it is characterised in that：It is existing
The peripheries field programmable gate array FPGA mount Clock management chip, filtering chip, electrical level transferring chip, BPI configuration chips and
Interface card, respectively receiving signal digital and the analog-digital converter ADC and digital analog converter DAC for emitting signal.
4. incoherent Spread Spectrum Digital transceiver instantaneous frequency measurement as described in claim 1 and demodulation method, it is characterised in that：
The plug-in a piece of BPI configuration chips of FPGA and Clock management chip CLK and Clock management chip CLK are aoxidized by complementary metal
Analog-digital converter ADC connected object semiconductor memory CMOS, wherein incoherent reception algoritic module input terminal is turned by modulus
Parallel operation ADC connected first is single-ended to turn both-end transformer and first filter, and analog-digital converter ADC turns both-end transformer by single-ended
Be connected first filter；FPGA output ends plug-in digital analog converter DAC, digital analog converter DAC turn single-end transformer by both-end
Be connected second filter.
5. incoherent Spread Spectrum Digital transceiver instantaneous frequency measurement as described in claim 1 and demodulation method, it is characterised in that：Expand
It takes place frequently and penetrates algoritic module and include：Data framing module, RS coding modules, differential encoding module, Direct Sequence Spread Spectrum module, symbol
The modules such as mapping block, modulation module and shaping filter, data framing module realize that user's bit streams are grown to form physics by anchor-frame
Layer transmission frame, and add and synchronized and the frame synchronization head of acquisition of information, frame information field for receiving terminal；RS coding modules are adopted
The RS codings of RS (15,11) format are realized with the IPcore in FPGA；Differential encoding module is using coding formula：Realize that difference is compiled
The coding output Out (k) of code, k moment is obtained by the exclusive or of the coding output Out (k-1) at input In (k) and the k-1 moment at k moment
It arrives；Direct Sequence Spread Spectrum module selects corresponding pseudo-code as expansion according to the PN codes number of user setting from pseudo-code sequence module
Frequency code spreads the user data bit streams of input；Data bit streams after spread spectrum realize biphase phase shift keying BPSK modulation
Symbol mapping, i.e., bit symbols 0 are mapped to -1 constellation point, and bit symbols 1 are mapped to+1 constellation point；Modulation module will input
Number of constellation points evidence be multiplied with the carrier wave cos that carrier wave generation module generates, obtain modulation output；Shaping filter module believes modulation
Filtering is formed in form factor number as required, and the later data of forming filter are sent to DAC and carry out digital-to-analogue conversion.
6. incoherent Spread Spectrum Digital transceiver instantaneous frequency measurement as described in claim 1 and demodulation method, it is characterised in that：It is non-
The data that coherent reception algoritic module exports Digital Down Converter Module are sent into instantaneous frequency measurement mould integrate-dump filter in the block
IDF be filtered extraction realize it is down-sampled, it is down-sampled after data by phase discriminator module recovery go out the Doppler in signal frequency
The possible maximum frequency range of carrier doppler is subdivided into multiple points of slots or segmentation by rate signal, with the center frequency of frequency slots
Rate is as Doppler shift, in the frequency slots separated in maximum possible frequency range, is carried out simultaneously using multiple search modules
Row search.
7. incoherent Spread Spectrum Digital transceiver instantaneous frequency measurement as described in claim 1 and demodulation method, it is characterised in that：It searches
When rope module is searched in a frequency slots, pseudo-code phase mobile search is carried out, realizes the two-dimensional search of Doppler and code phase
The current Doppler searched is divided slot frequency to eliminate frequency deviation by instantaneous frequency measurement；After dividing slot frequency to eliminate Doppler shift, move
Dynamic local code phase carries out all possible phase shift phase relevant search, and correlated results is compared with given thresholding, and determination is searched
Whether rope succeeds, and has searched for all frequency slots, regard correlated results as Doppler's frequency by the code phase values of frequency slots thresholding
Inclined and code phase deviation.
8. incoherent Spread Spectrum Digital transceiver instantaneous frequency measurement as described in claim 1 and demodulation method, it is characterised in that：It is defeated
Go out selecting module by the data corresponding to the maximum peak frequency slots and code phase that search, is sent to FFT accurate measurement frequency modules and carries out essence
Frequency measurement carries out complex transform using the fast algorithm of discrete fourier transform FFT, after fast Fourier transform FFT transform, carries out work(
Rate spectrum calculates, and modulus calculating is carried out using multiplier.
9. incoherent Spread Spectrum Digital transceiver instantaneous frequency measurement as described in claim 1 and demodulation method, it is characterised in that：Wink
When frequency measurement module final output instantaneous frequency measurement value be point slot frequency with accurate measurement frequency and, this and value are the carrier waves in data
Doppler shift, it is sent to controlled local oscillator module and generates corresponding quadrature carrier signals, the input with Digital Down Converter Module
Carrier doppler is eliminated in signal mixing.
10. incoherent Spread Spectrum Digital transceiver instantaneous frequency measurement as described in claim 1 and demodulation method, it is characterised in that：
Instantaneous frequency measurement module divides slot frequency to scan for code phase simultaneously using parallel 16 search modules, realizes that bigness scale frequency is worth；
In bigness scale frequency, the searcher of instantaneous frequency measurement module is since frequency-code phase divides the centre frequency f0 of slot frequency, to positive and negative two
Direction carries out parallel search outward；Searcher first eliminates the Doppler divided where slot, then exists when searching for some frequency slots
Code phase dimension sliding correlation intergal, correlation intergal export an integrated value to each code phase, and integrated value is more than design threshold value
When, the centre frequency of corresponding frequency slots is bigness scale frequency value at this time, and corresponding code phase is the thick phase of code.
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