CN106453177B - Fsk signal demodulation method and system for narrow band direct printing telegraph equipment - Google Patents

Fsk signal demodulation method and system for narrow band direct printing telegraph equipment Download PDF

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CN106453177B
CN106453177B CN201610856292.8A CN201610856292A CN106453177B CN 106453177 B CN106453177 B CN 106453177B CN 201610856292 A CN201610856292 A CN 201610856292A CN 106453177 B CN106453177 B CN 106453177B
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data
branch
unit
multiplier
correlation
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CN106453177A (en
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周建英
刘江南
罗新林
陈江平
朱建良
凌峰
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CETC Ningbo Maritime Electronics Research Institute Co Ltd
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CETC Ningbo Maritime Electronics Research Institute Co Ltd
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/10—Frequency-modulated carrier systems, i.e. using frequency-shift keying
    • H04L27/14—Demodulator circuits; Receiver circuits
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/10—Frequency-modulated carrier systems, i.e. using frequency-shift keying
    • H04L27/103—Chirp modulation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/10—Frequency-modulated carrier systems, i.e. using frequency-shift keying
    • H04L27/106—M-ary FSK
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L27/00—Modulated-carrier systems
    • H04L27/10—Frequency-modulated carrier systems, i.e. using frequency-shift keying
    • H04L27/14—Demodulator circuits; Receiver circuits
    • H04L27/144—Demodulator circuits; Receiver circuits with demodulation using spectral properties of the received signal, e.g. by using frequency selective- or frequency sensitive elements
    • H04L27/148—Demodulator circuits; Receiver circuits with demodulation using spectral properties of the received signal, e.g. by using frequency selective- or frequency sensitive elements using filters, including PLL-type filters

Abstract

The invention discloses a kind of fsk signal demodulation methods and system for narrow band direct printing telegraph equipment, design is simple, its synchronization signal needed for being demodulated using calling code field with uniqueness in the direct printing telegraph ARQ communication mode in narrowband as fsk signal, simultaneously according to the signal transmit cycle (450ms) of ARQ communication mode and automatic retransmission mechanism, realize the genlocing to the direct printing telegraph signal in narrowband, to realize the direct printing telegraph signal demodulation in narrowband, convenient for being promoted and applied in the pile line operation in the integrated circuits such as FPGA and DSP.The method of the present invention and system can be realized the demodulation of no synchronizing sequence short-term burst fsk signal, can be applied to based on the modulation systems such as frequency shift keying (FSK), minimum shift keying (MSK), Guassian Minimum Shift Keying GMSK (GMSK) without synchronizing sequence short-term burst communication product.

Description

Fsk signal demodulation method and system for narrow band direct printing telegraph equipment
Technical field
The invention belongs to digital communication technology fields, and in particular to a kind of FSK for narrow band direct printing telegraph equipment Signal demodulating method.
Background technique
At sea in mobile communication business, short wave communication all plays key player all the time.Wherein narrowband directly prints Word telegram (NBDP) equipment is even more one of the important component of Global Maritime Distress and Safety Syst (GMDSS).
There are two types of communication modes for the direct printing telegraph in narrowband: (the 4B3Y code of a 7bits indicates a character, B to Unit 7 =0, Y=1) selective communication mode (ARQ) and 7 cell broadcast communication modes (FEC).Using FSK modulation, modulation rate is The centre frequency of 100 bauds, frequency displacement 170Hz, the audible spectrum suitable for sender should be 1700Hz.
One ARQ calling period is 450ms, wherein including: main page station 210ms information word group launch time, (3 characters were total The information of 21bit), signal transmission time (information of 1 total 7bit of character), signal space transmission time are controlled by page station 70ms T1 and equipment delay t2 etc..Wherein, redundant signals are all not present in 21bits information word group and 7bits control signal.One ARQ is exhaled Make period basic timing as shown in Figure 1.
In the ARQ communication mode of the direct printing telegraph in narrowband, communicating pair establishes communication and needs with uniqueness exhale Be code field, which is made of 3 groups of 21bits calling word groups, the respectively first calling word group, the second calling word group, Third calls word group.And in ARQ communication process, communicating pair must strictly keep the calling period of 450ms.Detailed content ginseng Examine ITU-R M.625-4 recommendation " the direct printing telegraph apparatus of automatic identification is used in maritime mobile service ".
As can be seen that in selective communication, the direct printing telegraph in narrowband using a kind of irredundant sequence burst Communication mode determines facies-suite due to not including in the burst signal, and the common synchronous method based on theory of PLL is herein not It is applicable in.
Summary of the invention
The technical problem to be solved by the present invention is in view of the deficiencies of the prior art, provide one kind and directly print for narrowband The fsk signal demodulation method and system of word telegraphic instrument can be realized no synchronizing sequence short-term burst fsk signal demodulation, can answer For being based on the nothing of the modulation systems such as frequency shift keying (FSK), minimum shift keying (MSK), Guassian Minimum Shift Keying GMSK (GMSK) Synchronizing sequence short-term burst communication product.
The technical scheme of the invention to solve the technical problem is: for narrow band direct printing telegraph equipment Fsk signal demodulation method, the ARQ communication mode of the narrow band direct printing telegraph equipment establish with uniqueness needed for communication exhale Code field is made to be made of 3 groups of 21bits calling word groups, i.e., the first calling word group, the second calling word group and third call word group, should Fsk signal demodulation method the following steps are included:
(1) the FSK radiofrequency signal issued to narrow band direct printing telegraph equipment carries out quantization sampling and obtains radio frequency sampling number According to, then extraction processing is filtered to radio frequency sampled data, obtain the quadrature base band data IQ that sample rate is Fs=2400Hz；
(2) the corresponding instantaneous frequency values of quadrature base band data IQ are calculated, and 0 instantaneous frequency values of will be greater than or equal to are classified as 1, Instantaneous frequency values less than 0 are classified as -1, obtain the data after returning 1 or returning -1；
(3) by the data after returning 1 or returning -1, the FIFO that a depth is is stored at 21 points every K=24 point, obtains K simultaneously Row branch；
(4) K parallel branch and the first calling word group are subjected to relevant calculation respectively, when in K parallel branch Continuous L branch correlation peak be more than or equal to correlation threshold when, extract in continuous L branch in center branch Road is as optimal branch P；
(5) after optimal branch P delay buffer 450ms, optimal branch P and the second calling word group are slided first Dynamic relevant calculation；
If correlation peak is less than correlation threshold, repeatedly step (4), redefine optimal branch；
If correlation peak is greater than correlation threshold, after optimal branch P continues delay buffer 450ms, with the third Calling word group carries out sliding relevant calculation, if correlation peak is less than correlation threshold, repeatedly step (4), are redefined optimal Branch locks optimal branch P if correlation peak is greater than correlation threshold as synchronous branch, and make demodulation output.
Preferably, the determination process of optimal branch P is as follows in step (4):
Step 1: meeting quantity L, Ln expression of the correlation peak equal to the branch of correlation threshold by counter records and open The L of beginning correlation value calculationnA branch, when original state, L=0, n=1；
Step 2: taking LnThe data that a branch has cached；
Step 3: LnThe data and the first calling word group that a branch has cached carry out relevant calculation；
Step 4: determining whether correlation peak is equal to correlation threshold, if correlation peak is equal to correlation threshold, execute step Rapid 5, it is no to then follow the steps 6；
Step 5: as the L=L+1 of counter records, taking n=n+1, execute step 2~step 4；
Step 6: determine whether L is more than or equal to 5, if L >=5, step 7 is executed, it is no to then follow the steps 8；
Step 7: if n+ [L/2] > 24, taking optimal branch P=n+ [L/2] -24, otherwise take optimal branch P=n+ [L/ 2], wherein [L/2] indicates downward rounding operation；
Step 8: then counter O reset, L=0, n=n+1 execute to step 2, take LnThe data that a branch has cached Relevant calculation is carried out with the first calling word group, step 2~step 6 is repeated, until optimal branch P is determined.
Preferably, the determination process of synchronous branch is as follows in step (5):
Step a: after optimal branch P first time delay buffer 450ms, data cached sequence P is taken1；
Step b: data cached sequence P1Relevant calculation is carried out with the second calling word group；
Step c: determining whether correlation peak is equal to correlation threshold, if correlation peak is equal to correlation threshold, executes step Rapid d, otherwise repeatedly step (4), redefine optimal branch；
After step d: optimal branch P second of delay buffer 450ms, data cached sequence P is taken2；
Step e: data cached sequence P2Relevant calculation is carried out with the third calling word group；
Step f: determining whether correlation peak is equal to correlation threshold, if correlation peak is equal to correlation threshold, executes step Rapid g, otherwise repeatedly step (4), redefine optimal branch；
Step g: optimal branch P is locked as synchronous branch.
For the fsk signal demodulating system of narrow band direct printing telegraph equipment, including AD sampling unit, the number being sequentially connected Word down-converter unit, instantaneous frequency unit, serioparallel exchange unit, parallel sliding correlation unit and delay locked unit；
The output end of the AD sampling unit is connected with the input terminal of the Digital Down Convert unit, and the AD is adopted Sample unit is used to carry out the FSK radiofrequency signal that narrow band direct printing telegraph equipment issues quantization sampling and obtains radio frequency sampling number According to, and radio frequency sampled data is provided to the Digital Down Convert unit；
The output end of the Digital Down Convert unit is connected with the input terminal of the instantaneous frequency unit, the number Word down-converter unit is used to be filtered radio frequency sampled data extraction processing, obtains the orthogonal basis that sample rate is Fs=2400Hz Band data IQ, and quadrature base band data IQ is provided to the instantaneous frequency unit；
The output end of the instantaneous frequency unit is connected with the input terminal of the serioparallel exchange unit, and described is instantaneous Frequency cells are for calculating the corresponding instantaneous frequency values of quadrature base band data IQ, and 0 instantaneous frequency values of will be greater than or equal to are classified as 1, the instantaneous frequency values less than 0 are classified as -1, obtain the data after returning 1 or returning -1, and provide to the serioparallel exchange unit Data after returning 1 or returning -1；
The output end of the serioparallel exchange unit is connected with the input terminal of the parallel sliding correlation unit, described Serioparallel exchange unit is used for the data after returning 1 or returning -1, is stored in the FIFO that a depth is at 21 points every K=24 point, obtains K A parallel branch；
The output end of the parallel sliding correlation unit is connected with the input terminal of the delay locked unit, described Parallel sliding correlation unit is for carrying out relevant calculation for K parallel branch and the first calling word group respectively, when K parallel branch In the correlation peak of continuous L branch when being more than or equal to correlation threshold, extract and be in center in continuous L branch Branch is as optimal branch P；
The delay locked unit is used for after optimal branch P delay buffer 450ms, by by optimal branch P and the Two calling word groups, third calling word group carry out sliding relevant calculation, and locking synchronization branch simultaneously makees demodulation output.
Preferably, the Digital Down Convert unit includes the first multiplier, the first CIC decimation filter, the first FIR Decimation filter, digital controlled oscillator, the second multiplier, the 2nd CIC decimation filter and the 2nd FIR decimation filter, it is described AD sampling unit, the first multiplier, the first CIC decimation filter and the first FIR decimation filter are sequentially connected, and described first FIR decimation filter is for exporting orthogonal signalling data I；The AD sampling unit, the second multiplier, the 2nd CIC extract filter Wave device and the 2nd FIR decimation filter are sequentially connected, and the 2nd FIR decimation filter is for exporting in-phase signal data Q； The digital controlled oscillator is connected with first multiplier and the second multiplier respectively.
Preferably, the instantaneous frequency unit includes the first delay unit, the second delay unit, third delay list Member, the 4th multiplier, the 5th multiplier, the 6th multiplier, subtracter, adder, is removed the 4th delay unit, third multiplier The input terminal of musical instruments used in a Buddhist or Taoist mass and normalization unit, first delay unit and second delay unit is respectively with described The output end of one FIR decimation filter is connected, tetra- tunnel orthogonal signalling data I Fen Wei, i.e. first via orthogonal signalling data, Second tunnel orthogonal signalling data, third road orthogonal signalling data and the 4th tunnel orthogonal signalling data, the orthogonal letter of the first via Number is sent directly into the third multiplier, and the second tunnel orthogonal signalling data are prolonged through first delay unit When one caching period after be sent into the 5th multiplier, the third road orthogonal signalling data are sent directly into described the Four multipliers, the 4th tunnel orthogonal signalling data are sent into institute after second delay unit is delayed a caching period The 4th multiplier stated；The input terminal of the third delay unit and the 4th delay unit is respectively with described second The output end of FIR decimation filter is connected, tetra- tunnel in-phase signal data Q Fen Wei, i.e. first via in-phase signal data, the Two tunnel in-phase signal data, third road in-phase signal data and the 4th tunnel in-phase signal data, the first via in-phase signal Data are sent into the third multiplier after the third delay unit is delayed a caching period, and second tunnel is same It is believed that number is sent directly into the 5th multiplier, the third road in-phase signal data are single through the 4th delay Member is sent into the 6th multiplier after one caching period of delay, the 4th tunnel in-phase signal data are sent directly into described The 6th multiplier；The output end of the third multiplier and the 5th multiplier is defeated with the subtracter respectively Enter end to be connected, the output end of the 4th multiplier and the 6th multiplier input terminal with the adder respectively Be connected, the output end of the output end of the subtracter and the adder respectively with the input terminal phase of the divider Even, the output end of the divider is connected with the input terminal of the normalization unit, described in the data warp after returning 1 or returning -1 Normalization unit output end output.
Compared with the prior art, the advantages of the present invention are as follows: it is disclosed by the invention to be used for narrow band direct printing telegraph equipment Fsk signal demodulation method and system, design is simple, unique using having in the direct printing telegraph ARQ communication mode in narrowband Property calling code field as synchronization signal needed for fsk signal demodulation, while according to the signal transmit cycle of ARQ communication mode (450ms) and automatic retransmission mechanism realizes the genlocing to the direct printing telegraph signal in narrowband, to realize that narrowband directly prints Word telegraphic signal demodulation, convenient for being promoted and applied in the pile line operation in the integrated circuits such as FPGA and DSP.The method of the present invention and System can be realized no synchronizing sequence short-term burst fsk signal demodulation, can be applied to based on frequency shift keying (FSK), minimum shift frequency The modulation systems such as keying (MSK), Guassian Minimum Shift Keying GMSK (GMSK) without synchronizing sequence short-term burst communication product.
Detailed description of the invention
Fig. 1 is that an ARQ of narrow band direct printing telegraph equipment calls the basic timing in period；
Fig. 2 is the structure connection diagram of demodulating system of the present invention；
Fig. 3 is the structural schematic diagram of Digital Down Convert unit in demodulating system of the present invention；
Fig. 4 is the structural schematic diagram of instantaneous frequency unit in demodulating system of the present invention；
Fig. 5 is that the data of serioparallel exchange unit in demodulating system of the present invention convert schematic diagram；
Fig. 6 is the flow chart of optimal branch P determination process in demodulation method of the present invention, i.e., the signal stream of parallel sliding unit Cheng Tu；
Fig. 7 is the flow chart of synchronous branch determination process in demodulation method of the present invention, i.e., the signal stream of delay locked unit Cheng Tu.
Specific embodiment
The present invention will be described in further detail below with reference to the embodiments of the drawings.
The fsk signal demodulation method for narrow band direct printing telegraph equipment of embodiment, the direct printing telegraph in the narrowband Calling code field with uniqueness needed for the ARQ communication mode of equipment establishes communication is made of 3 groups of 21bits calling word groups, i.e., First calling word group, second calling word group and third call word group, the fsk signal demodulation method the following steps are included:
(1) the FSK radiofrequency signal issued to narrow band direct printing telegraph equipment carries out quantization sampling and obtains radio frequency sampling number According to, then extraction processing is filtered to radio frequency sampled data, obtain the quadrature base band data IQ that sample rate is Fs=2400Hz；
(2) the corresponding instantaneous frequency values of quadrature base band data IQ are calculated, and 0 instantaneous frequency values of will be greater than or equal to are classified as 1, Instantaneous frequency values less than 0 are classified as -1, obtain the data after returning 1 or returning -1；
(3) by the data after returning 1 or returning -1, the FIFO that a depth is is stored at 21 points every K=24 point, obtains K simultaneously Row branch；
(4) K parallel branch and the first calling word group are subjected to relevant calculation respectively, when in K parallel branch The correlation peak of continuous L branch (L >=5) when being more than or equal to correlation threshold, extract and be in center in continuous L branch The branch of position is as optimal branch P, as shown in fig. 6, specific determination process is as follows:
Step 1: meeting quantity L, Ln expression of the correlation peak equal to the branch of correlation threshold by counter records and open The L of beginning correlation value calculationnA branch, when original state, L=0, n=1；
Step 2: taking LnThe data that a branch has cached；
Step 3: LnThe data and the first calling word group that a branch has cached carry out relevant calculation；
Step 4: determining whether correlation peak is equal to correlation threshold, if correlation peak is equal to correlation threshold, execute step Rapid 5, it is no to then follow the steps 6；
Step 5: as the L=L+1 of counter records, taking n=n+1, execute step 2~step 4；
Step 6: determine whether L is more than or equal to 5, if L >=5, step 7 is executed, it is no to then follow the steps 8；
Step 7: if n+ [L/2] > 24, taking optimal branch P=n+ [L/2] -24, otherwise take optimal branch P=n+ [L/ 2], wherein [L/2] indicates downward rounding operation；
Step 8: then counter O reset, L=0, n=n+1 execute to step 2, take LnThe data that a branch has cached Relevant calculation is carried out with the first calling word group, step 2~step 6 is repeated, until optimal branch P is determined；
(5) after optimal branch P delay buffer 450ms, optimal branch P and the second calling word group are slided first Dynamic relevant calculation；
If correlation peak is less than correlation threshold, repeatedly step (4), redefine optimal branch；
If correlation peak is greater than correlation threshold, after optimal branch P continues delay buffer 450ms, with the third Calling word group carries out sliding relevant calculation, if correlation peak is less than correlation threshold, repeatedly step (4), are redefined optimal Branch locks optimal branch P if correlation peak is greater than correlation threshold as synchronous branch, and make demodulation output, wherein such as Shown in Fig. 7, the determination process of synchronous branch is as follows:
Step a: after optimal branch P first time delay buffer 450ms, data cached sequence P is taken1；
Step b: data cached sequence P1Relevant calculation is carried out with the second calling word group；
Step c: determining whether correlation peak is equal to correlation threshold, if correlation peak is equal to correlation threshold, executes step Rapid d, otherwise repeatedly step (4), redefine optimal branch；
After step d: optimal branch P second of delay buffer 450ms, data cached sequence P is taken2；
Step e: data cached sequence P2Relevant calculation is carried out with the third calling word group；
Step f: determining whether correlation peak is equal to correlation threshold, if correlation peak is equal to correlation threshold, executes step Rapid g, otherwise repeatedly step (4), redefine optimal branch；
Step g: optimal branch P is locked as synchronous branch.
Fsk signal demodulating system for narrow band direct printing telegraph equipment, it can be achieved that above-mentioned fsk signal demodulation method, As shown in Fig. 2, the fsk signal demodulating system includes the AD sampling unit 1 being sequentially connected, Digital Down Convert unit 2, instantaneous frequency Unit 3, serioparallel exchange unit 4, parallel sliding correlation unit 5 and delay locked unit 6.
The output end of AD sampling unit 1 is connected with the input terminal of Digital Down Convert unit 2, and AD sampling unit 1 is used for narrow Quantization sampling is carried out with the FSK radiofrequency signal that direct printing telegraph apparatus issues and obtains radio frequency sampled data, and to becoming under number Frequency unit 2 provides radio frequency sampled data.
The output end of Digital Down Convert unit 2 is connected with the input terminal of instantaneous frequency unit 3, and Digital Down Convert unit 2 is used In being filtered extraction processing to radio frequency sampled data, sample rate is obtained as the quadrature base band data IQ of Fs=2400Hz, and to Instantaneous frequency unit provides quadrature base band data IQ.As shown in figure 3, Digital Down Convert unit 2 includes the first multiplier 21, first CIC decimation filter 22, the first FIR decimation filter 23, digital controlled oscillator 24, the second multiplier 25, the 2nd CIC filtering extraction Device 26 and the 2nd FIR decimation filter 27, AD sampling unit 1, the first multiplier 21, the first CIC decimation filter 22 and first FIR decimation filter 23 is sequentially connected, and the first FIR decimation filter 23 is for exporting orthogonal signalling data I；AD sampling unit 1, Second multiplier 25, the 2nd CIC decimation filter 26 and the 2nd FIR decimation filter 27 are sequentially connected, the 2nd FIR filtering extraction Device 27 is for exporting in-phase signal data Q；Digital controlled oscillator 24 is connected with the first multiplier 21 and the second multiplier 25 respectively.AD After being multiplied using data with the cosine of digital controlled oscillator 24 and sinusoidal signal, orthogonal signalling data I and in-phase signal data are obtained Q, data I are extracted through the first CIC decimation filter 22 and 23 filtering extraction of the first FIR decimation filter, data Q through the 2nd CIC 27 filtering extraction of filter 26 and the 2nd FIR decimation filter, obtain using frequency for the baseband I circuit-switched data of Fs=2400Hz and Base band Q circuit-switched data, i.e. quadrature base band data IQ.
The output end of instantaneous frequency unit 3 is connected with the input terminal of serioparallel exchange unit 4, and instantaneous frequency unit 3 is based on The corresponding instantaneous frequency values of quadrature base band data IQ are calculated, and 0 instantaneous frequency values of will be greater than or equal to are classified as 1, it will be instantaneous less than 0 Frequency values are classified as -1, obtain the data after returning 1 or returning -1, and provide the data after returning 1 or returning -1 to serioparallel exchange unit 4.Such as Shown in Fig. 4, instantaneous frequency unit 3 prolongs including the first delay unit 31, the second delay unit 32, third delay unit the 33, the 4th Shi Danyuan 34, third multiplier 35, the 4th multiplier 36, the 5th multiplier 37, the 6th multiplier 38, subtracter 71, adder 72, the input terminal of divider 73 and normalization unit 74, the first delay unit 31 and the second delay unit 32 respectively with the first FIR The output end of decimation filter 23 is connected, and tetra- tunnel orthogonal signalling data I Fen Wei, i.e. first via orthogonal signalling data, the second tunnel are just Signal data, third road orthogonal signalling data and the 4th tunnel orthogonal signalling data, first via orthogonal signalling data are handed over to be sent directly into Third multiplier 35, the second tunnel orthogonal signalling data obtain I after the first delay unit 31 is delayed a caching period1Data, It is sent into the 5th multiplier 37, third road orthogonal signalling data are sent directly into the 4th multiplier 36, the 4th tunnel orthogonal signalling data warp Second delay unit 32 obtains I after one caching period of delay1Data are sent into the 4th multiplier 36；33 He of third delay unit The input terminal of 4th delay unit 34 is connected with the output end of the 2nd FIR decimation filter 27 respectively, and in-phase signal data Q points are Four tunnels, i.e. first via in-phase signal data, the second tunnel in-phase signal data, third road in-phase signal data and the 4th tunnel are same to be believed Number, first via in-phase signal data obtain Q after third delay unit 33 is delayed a caching period1Data are sent into the Three multipliers 35, the second tunnel in-phase signal data are sent directly into the 5th multiplier 37, and third road in-phase signal data are prolonged through the 4th Shi Danyuan 34 obtains Q after one caching period of delay1Data, are sent into the 6th multiplier 38, and the 4th tunnel in-phase signal data are direct It is sent into the 6th multiplier 38；The output end of third multiplier 35 and the 5th multiplier 37 input terminal phase with subtracter 71 respectively Even, the output end of the 4th multiplier 36 and the 6th multiplier 38 is connected with the input terminal of adder 72 respectively, subtracter 71 it is defeated The output end of outlet and adder 72 is connected with the input terminal of divider 73 respectively, the output end and normalization unit of divider 73 74 input terminal is connected, and the data after returning 1 or returning -1 are exported through the output end of normalization unit 74.As shown in figure 4, third multiplication Device 35 exports I*Q1Data, the 5th multiplier 37 export Q*I1Data, I*Q1Data and Q*I1Data are sent into subtracter 71；4th Multiplier 36 exports I*I1Data, the 6th multiplier 38 export Q*Q1Data, I*I1Data and Q*Q1Data are sent into adder 72； Subtracter 71 exports I*Q1-Q*I1Data, adder 72 export I*I1+Q*Q1Data；I*Q1-Q*I1Data and I*I1+Q*Q1Data It is sent into divider 73, the output of divider 73 is sent into normalization unit 74, obtains the data after returning 1 or returning -1.
The output end of serioparallel exchange unit 4 is connected with the input terminal of parallel sliding correlation unit 5, and serioparallel exchange unit 4 is used Data after it will return 1 or return -1 are stored in the FIFO that a depth is at 21 points every K=24 point, obtain K parallel branch.String And the data transformation schematic diagram of converting unit 4 is as shown in Figure 5.
The output end of parallel sliding correlation unit 5 is connected with the input terminal of delay locked unit 6, slides correlation unit parallel 5 for carrying out relevant calculation for K parallel branch and the first calling word group respectively, when the continuous L branch in K parallel branch When the correlation peak of (L >=5) is more than or equal to correlation threshold, the branch conduct in continuous L branch in center is extracted Optimal branch P.The signal flow graph of parallel sliding unit 5 is as shown in Figure 6.
Delay locked unit 6 is used for after optimal branch P delay buffer 450ms, by calling optimal branch P and second Word group, third calling word group carry out sliding relevant calculation, and locking synchronization branch simultaneously makees demodulation output.The letter of delay locked unit 6 Number flow chart is as shown in Figure 7.

Claims (6)

1. being used for the fsk signal demodulation method of narrow band direct printing telegraph equipment, the ARQ of the narrow band direct printing telegraph equipment is logical Calling code field with uniqueness needed for letter mode establishes communication is made of 3 groups of 21bits calling word groups, i.e., the first calling word Group, second calling word group and third call word group, it is characterised in that the fsk signal demodulation method the following steps are included:
(1) the FSK radiofrequency signal issued to narrow band direct printing telegraph equipment carries out quantization sampling and obtains radio frequency sampled data, then Extraction processing is filtered to radio frequency sampled data, obtains the quadrature base band data IQ that sample rate is Fs=2400Hz；
(2) the corresponding instantaneous frequency values of quadrature base band data IQ are calculated, and 0 instantaneous frequency values of will be greater than or equal to are classified as 1, it will be small Instantaneous frequency values in 0 are classified as -1, obtain the data after returning 1 or returning -1；
(3) by the data after returning 1 or returning -1, the FIFO that a depth is is stored at 21 points every K=24 point, obtains K parallel branch Road；
(4) K parallel branch and the first calling word group are subjected to relevant calculation respectively, the company in K parallel branch When the correlation peak of continuous L branch is more than or equal to correlation threshold, extracts the branch in continuous L branch in center and make For optimal branch P；
(5) after optimal branch P delay buffer 450ms, optimal branch P and the second calling word group are subjected to sliding phase first It closes and calculates；
If correlation peak is less than correlation threshold, repeatedly step (4), redefine optimal branch；
If correlation peak is greater than correlation threshold, after optimal branch P continues delay buffer 450ms, called with the third Word group carries out sliding relevant calculation, if correlation peak is less than correlation threshold, repeatedly step (4), redefine optimal branch, If correlation peak is greater than correlation threshold, optimal branch P is locked as synchronous branch, and make demodulation output.
2. the fsk signal demodulation method according to claim 1 for narrow band direct printing telegraph equipment, it is characterised in that The determination process of optimal branch P is as follows in step (4):
Step 1: meeting correlation peak by counter records indicates beginning phase equal to the quantity L, Ln of the branch of correlation threshold The L that pass value calculatesnA branch, when original state, L=0, n=1；
Step 2: taking LnThe data that a branch has cached；
Step 3: LnThe data and the first calling word group that a branch has cached carry out relevant calculation；
Step 4: determine whether correlation peak is equal to correlation threshold, if correlation peak is equal to correlation threshold, executes step 5, It is no to then follow the steps 6；
Step 5: as the L=L+1 of counter records, taking n=n+1, execute step 2~step 4；
Step 6: determine whether L is more than or equal to 5, if L >=5, step 7 is executed, it is no to then follow the steps 8；
Step 7: if n+ [L/2] > 24, optimal branch P=n+ [L/2] -24 is taken, otherwise takes optimal branch P=n+ [L/2], In [L/2] indicate downward rounding operation；
Step 8: then counter O reset, L=0, n=n+1 execute to step 2, take LnThe data and institute that a branch has cached The the first calling word group stated carries out relevant calculation, step 2~step 6 is repeated, until optimal branch P is determined.
3. the fsk signal demodulation method according to claim 1 or 2 for narrow band direct printing telegraph equipment, feature It is that the determination process of synchronous branch in step (5) is as follows:
Step a: after optimal branch P first time delay buffer 450ms, data cached sequence P is taken1；
Step b: data cached sequence P1Relevant calculation is carried out with the second calling word group；
Step c: determining whether correlation peak is equal to correlation threshold, if correlation peak is equal to correlation threshold, executes step d, Otherwise step (4) are repeated, redefines optimal branch；
After step d: optimal branch P second of delay buffer 450ms, data cached sequence P is taken2；
Step e: data cached sequence P2Relevant calculation is carried out with the third calling word group；
Step f: determining whether correlation peak is equal to correlation threshold, if correlation peak is equal to correlation threshold, executes step g, Otherwise step (4) are repeated, redefines optimal branch；
Step g: optimal branch P is locked as synchronous branch.
4. being used for the fsk signal demodulating system of narrow band direct printing telegraph equipment, it is characterised in that the AD including being sequentially connected is adopted Sample unit, Digital Down Convert unit, instantaneous frequency unit, serioparallel exchange unit, parallel sliding correlation unit and delay locked list Member；
The output end of the AD sampling unit is connected with the input terminal of the Digital Down Convert unit, and the AD samples single Member obtains radio frequency sampled data for carrying out quantization sampling to the FSK radiofrequency signal that narrow band direct printing telegraph equipment issues, and Radio frequency sampled data is provided to the Digital Down Convert unit；
The output end of the Digital Down Convert unit is connected with the input terminal of the instantaneous frequency unit, under the number Converter unit is used to be filtered radio frequency sampled data extraction processing, obtains the quadrature base band number that sample rate is Fs=2400Hz Quadrature base band data IQ is provided according to IQ, and to the instantaneous frequency unit；
The output end of the instantaneous frequency unit is connected with the input terminal of the serioparallel exchange unit, the instantaneous frequency Unit is for calculating the corresponding instantaneous frequency values of quadrature base band data IQ, and 0 instantaneous frequency values of will be greater than or equal to are classified as 1, will Instantaneous frequency values less than 0 are classified as -1, obtain the data after returning 1 or returning -1, and to the serioparallel exchange unit offer return 1 or Data after returning -1；
The output end of the serioparallel exchange unit is connected with the input terminal of the parallel sliding correlation unit, and the string is simultaneously Converting unit is used for the data after returning 1 or returning -1, is stored in the FIFO that a depth is at 21 points every K=24 point, obtains K simultaneously Row branch；
The output end of the parallel sliding correlation unit is connected with the input terminal of the delay locked unit, and described is parallel Correlation unit is slided for K parallel branch and the first calling word group to be carried out relevant calculation respectively, when in K parallel branch When the correlation peak of continuous L branch is more than or equal to correlation threshold, the branch that center is in continuous L branch is extracted As optimal branch P；
The delay locked unit is used for after optimal branch P delay buffer 450ms, by exhaling optimal branch P with second Word group, third calling word group is made to carry out sliding relevant calculation, locking synchronization branch simultaneously makees demodulation output.
5. the fsk signal demodulating system according to claim 4 for narrow band direct printing telegraph equipment, it is characterised in that The Digital Down Convert unit includes the first multiplier, the first CIC decimation filter, the first FIR decimation filter, numerical control vibration Device, the second multiplier, the 2nd CIC decimation filter and the 2nd FIR decimation filter are swung, the AD sampling unit, first multiply Musical instruments used in a Buddhist or Taoist mass, the first CIC decimation filter and the first FIR decimation filter are sequentially connected, and the first FIR decimation filter is used for Export orthogonal signalling data I；AD sampling unit, the second multiplier, the 2nd CIC decimation filter and the 2nd FIR is extracted Filter is sequentially connected, and the 2nd FIR decimation filter is for exporting in-phase signal data Q；The digital controlled oscillator It is connected respectively with first multiplier and the second multiplier.
6. the fsk signal demodulating system according to claim 5 for narrow band direct printing telegraph equipment, it is characterised in that The instantaneous frequency unit includes the first delay unit, the second delay unit, third delay unit, the 4th delay unit, the Three multipliers, the 4th multiplier, the 5th multiplier, the 6th multiplier, subtracter, adder, divider and normalization unit, institute The input terminal of the first delay unit and second delay unit stated is defeated with the first FIR decimation filter respectively Outlet is connected, tetra- tunnel orthogonal signalling data I Fen Wei, i.e., first via orthogonal signalling data, the second tunnel orthogonal signalling data, Third road orthogonal signalling data and the 4th tunnel orthogonal signalling data, the first via orthogonal signalling data are sent directly into described Third multiplier, the second tunnel orthogonal signalling data are sent into after first delay unit is delayed a caching period 5th multiplier, the third road orthogonal signalling data are sent directly into the 4th multiplier, and the described the 4th Road orthogonal signalling data are sent into the 4th multiplier after second delay unit is delayed a caching period；It is described Third delay unit and the 4th delay unit the input terminal output with the 2nd FIR decimation filter respectively End is connected, tetra- tunnel in-phase signal data Q Fen Wei, i.e. first via in-phase signal data, the second tunnel in-phase signal data, the Three tunnel in-phase signal data and the 4th tunnel in-phase signal data, the first via in-phase signal data are delayed through the third Unit is sent into the third multiplier after one caching period of delay, the second tunnel in-phase signal data are sent directly into institute The 5th multiplier stated, the third road in-phase signal data are after the 4th delay unit is delayed a caching period It is sent into the 6th multiplier, the 4th tunnel in-phase signal data are sent directly into the 6th multiplier；Described The output end of third multiplier and the 5th multiplier is connected with the input terminal of the subtracter respectively, and the described the 4th The output end of multiplier and the 6th multiplier is connected with the input terminal of the adder respectively, the subtracter Output end and the output end of the adder are connected with the input terminal of the divider respectively, the output of the divider End is connected with the input terminal of the normalization unit, output end of the data after returning 1 or returning -1 through the normalization unit Output.
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