CN110995393B - Meteor trail autonomous frequency-changing burst modulation-demodulation device - Google Patents
Meteor trail autonomous frequency-changing burst modulation-demodulation device Download PDFInfo
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- CN110995393B CN110995393B CN201911196632.9A CN201911196632A CN110995393B CN 110995393 B CN110995393 B CN 110995393B CN 201911196632 A CN201911196632 A CN 201911196632A CN 110995393 B CN110995393 B CN 110995393B
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/0001—Systems modifying transmission characteristics according to link quality, e.g. power backoff
- H04L1/0009—Systems modifying transmission characteristics according to link quality, e.g. power backoff by adapting the channel coding
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/0078—Avoidance of errors by organising the transmitted data in a format specifically designed to deal with errors, e.g. location
- H04L1/0083—Formatting with frames or packets; Protocol or part of protocol for error control
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D30/00—Reducing energy consumption in communication networks
- Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks
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Abstract
The invention discloses an autonomous frequency-changing burst modulation and demodulation device for meteor trail, and relates to the technical field of meteor trail communication. The device comprises an automatic frequency-changing protocol controller, an encoder, a modulator, a D/A converter, a band-pass filter, an automatic frequency-changing monitor, a sweep frequency detector, a decoder, a multi-channel parallel demodulator, an A/D converter, a gain amplifier and a power supply. The invention can autonomously change frequency in real time according to the site environment, simplifies the link opening process, improves the anti-interference capability and transmission reliability of the system, and is particularly suitable for meteor trail communication with strong burst and fading channels.
Description
Technical Field
The invention discloses an autonomous frequency-changing burst modulation and demodulation device for meteor trail, and relates to the technical field of meteor trail communication.
Background
For meteor trail communication, the available working frequency is 30 MHz-120 MHz, wherein 40 MHz-50 MHz can better exert the performance of meteor trail, and the most obvious characteristics of the channel are burstiness and time-varying property of channel fading.
The selection of the optimal working frequency can fully utilize weak signals and improve the signal-to-noise ratio of the vestige signals. Generally, there are two methods for selecting the working frequency, one is to manually select the optimal working frequency by an instrument and to notify the opposite end by other communication means, which has the disadvantage that the dependence on the instrument, the manual work and other communication methods cannot be got rid of, causing great inconvenience in implementation; the other method is that based on a large amount of historical communication records, available communication frequency bands and frequency points are stored in a FLASH ROM to provide reference for selection of meteor trail communication channels, and the defects that historical data observed by each station for a long time are needed, and the channel state cannot be reliably reflected in real time in actual communication.
Disclosure of Invention
The invention aims to avoid the defects in the background art and provide the meteor trail autonomous frequency-changing burst modulation and demodulation device, which can autonomously change the receiving frequency into the working frequency with the minimum local interference according to the electromagnetic environment and the communication performance of a station, enhance the anti-interference capability of a system and improve the channel utilization rate and the transmission reliability.
The purpose of the invention is realized as follows:
a meteor trail autonomous frequency-changing burst modulation-demodulation device comprises a D/A converter 4, a band-pass filter 5, a sweep detector 7, an A/D converter 10, a gain amplifier 11, a power supply 12 and an FPGA, wherein the FPGA is used for realizing an autonomous frequency-changing protocol controller 1, an encoder 2, a modulator 3, an autonomous frequency-changing monitor 6, a decoder 8 and a multichannel parallel demodulator 9;
the automatic frequency-changing protocol controller 1 performs framing processing on service data input by an external port A and then sends the service data and control information to the encoder 2; the encoder encodes the information and sends the encoded information to the modulator 3; the modulator 3 modulates the input data and outputs the modulated data to the D/A converter 4; the D/A converter 4 converts the modulation signal into an analog signal and outputs the analog signal to the band-pass filter 5; the band-pass filter 5 filters the input signal and outputs the filtered signal to the outside through an output port B; the sweep frequency detector 7 detects the receiving level of each frequency point in the communication frequency band through an external input port C and sends the receiving level to the autonomous frequency changing monitor 6; the autonomous frequency-changing monitor 6 obtains the optimal receiving frequency by comparing the receiving level value and sends the optimal receiving frequency to the autonomous frequency-changing protocol controller 1; the autonomous frequency changing protocol controller 1 determines whether frequency changing is needed or not by evaluating the current communication condition, and if a signal is not received for a long time, the current communication effect is considered to be poor and the frequency changing is needed; when the frequency is changed, the frequency point information is framed and sent to the modulator 3, and then the frequency point information is output through the output port B after passing through the D/A converter 4 and the band-pass filter 5; the gain amplifier 11 receives the intermediate frequency signal through an external input port D, performs gain control on the received signal, stabilizes an output signal, and sends the output signal to the a/D converter 10; the A/D converter 10 converts the analog signal into a digital signal and sends the digital signal to the multichannel parallel demodulator 9; the multichannel parallel demodulator 9 carries out down-conversion, filtering and coherent demodulation on the signals, identifies the speed type and the channel number from the demodulated data, then sends the demodulated data to the decoder 8 for decoding, and sends the decoded data to the autonomous frequency-changing protocol controller 1; the autonomous frequency-changing protocol controller 1 identifies the decoded data, processes the service information and sends the processed service information to an output port E if the decoded data is service information, and sends the frequency-changing information to the modulator 3 to complete frequency change if the decoded data is frequency-changing information.
Further, the multichannel parallel demodulator 9 includes N digital down converters, N digital filters, N coherent detectors, N timing extractors, a frame header and channel number identifier 17, and a signal gate 18, where N is greater than or equal to 2;
the N digital down converters receive the digital signals sent from the D/a converter 10 in parallel, and send the digital signals to the N digital filters after performing down conversion processing on the digital signals; n digital filters filter input signals, and the filtered signals are respectively sent to N timing extractors to extract timing signals; each path of filtered signal and the timing signal corresponding to the filtered signal are sent to a corresponding coherent detector to obtain a corresponding demodulation signal; then, the demodulated signal is sent to a frame header and channel identifier 17 to identify a rate code and a receiving channel number; finally, the identified rate code and the receiving channel number are sent to the signal gating device 18 together with the timing signal, and the corresponding demodulation information is gated in the signal gating device 18 and sent to the decoder 8.
Compared with the background art, the invention has the following advantages:
1. the invention can realize the automatic frequency change of meteor trail communication, and when the link is opened, the invention does not need to rely on additional instruments and human intervention, does not depend on other communication means, and automatically changes the communication into the optimal working frequency.
2. The invention can evaluate the communication effect in the communication process, and if the working frequency is interfered and the communication effect is not good, the receiving frequency is switched autonomously, thereby improving the anti-interference capability and the transmission reliability of the system.
In a word, the invention can autonomously change frequency in real time according to the site environment, simplifies the link opening process, improves the anti-interference capability and transmission reliability of the system, and is particularly suitable for meteor trail communication of sudden strong and fading channels.
Drawings
Fig. 1 is an electrical schematic block diagram of an autonomous meteoric trail frequency-changing burst modem according to an embodiment of the present invention.
Fig. 2 is an electrical schematic block diagram of the multi-channel parallel demodulator of fig. 1.
Detailed Description
The invention is further described with reference to the following figures and detailed description.
As shown in fig. 1, an autonomous frequency-changing burst modem for meteor trail includes a D/a converter 4, a band-pass filter 5, a sweep detector 7, an a/D converter 10, a gain amplifier 11, a power supply 12, and an FPGA, where the FPGA is used to implement an autonomous frequency-changing protocol controller 1, an encoder 2, a modulator 3, an autonomous frequency-changing monitor 6, a decoder 8, and a multichannel parallel demodulator 9;
the automatic frequency-changing protocol controller 1 performs framing processing on service data input by an external port A and then sends the service data and control information to the encoder 2; the encoder encodes the information and sends the encoded information to the modulator 3; the modulator 3 modulates the input data and outputs the modulated data to the D/A converter 4; the D/A converter 4 converts the modulation signal into an analog signal and outputs the analog signal to the band-pass filter 5; the band-pass filter 5 filters the input signal and outputs the filtered signal to the outside through an output port B; the sweep frequency detector 7 detects the receiving level of each frequency point in the communication frequency band through an external input port C and sends the receiving level to the autonomous frequency changing monitor 6; the autonomous frequency-changing monitor 6 obtains the optimal receiving frequency by comparing the receiving level value and sends the optimal receiving frequency to the autonomous frequency-changing protocol controller 1; the autonomous frequency-changing protocol controller 1 determines whether frequency changing is needed or not by evaluating the current communication condition, and if a signal is not received for a long time, the current communication effect is considered to be poor and the frequency changing is needed; when the frequency is changed, the frequency point information is framed and sent to the modulator 3, and then the frequency point information is output through the output port B after passing through the D/A converter 4 and the band-pass filter 5; the gain amplifier 11 receives the intermediate frequency signal through an external input port D, performs gain control on the received signal, stabilizes an output signal, and sends the output signal to the a/D converter 10; the A/D converter 10 converts the analog signal into a digital signal and sends the digital signal to the multichannel parallel demodulator 9; the multichannel parallel demodulator 9 carries out down-conversion, filtering and coherent demodulation on the signals, identifies the speed type and the channel number from the demodulated data, then sends the demodulated data to the decoder 8 for decoding, and sends the decoded data to the autonomous frequency-changing protocol controller 1; the autonomous frequency-changing protocol controller 1 identifies the decoded data, processes the service information and sends the processed service information to the output port E if the decoded data is service information, and sends the frequency-changing information to the modulator 3 to complete the frequency change if the decoded data is frequency-changing information.
In the embodiment, the autonomous frequency-changing protocol controller 1, the encoder 2, the modulator 3, the autonomous frequency-changing monitor 6, the sweep frequency detector 7, the decoder 8 and the multichannel parallel demodulator 9 can be all made of SMQ4VSX55FF1148 and SMQ4VLX200FF1513 chips manufactured by the ministronics of republic of China, the D/a converter 10 can be made of an AD9434 chip manufactured by the AD company of america, the a/D converter 4 can be made of an AD9788 chip manufactured by the AD company of america, the band-pass filter 5 can be made of SBPS-45 manufactured by the microwave company of republic of japan, and the gain amplifier 11 can be made of an AD8367 manufactured by the AD company.
The power supply 12 provides the dc working voltage of the whole modem device, and can be manufactured by a commercially available general module integrated with a regulated dc power supply, and the output + V voltage is + 5V.
As shown in FIG. 2, the multi-channel parallel demodulator 9 comprises 4 digital down-converters 13-1 to 13-4, 4 digital filters 14-1 to 14-4, 4 coherent detectors 15-1 to 15-4, 4 timing extractors 16-1 to 16-4, a frame header and channel number identifier 17 and a signal gating device 18;
the digital down converters 13-1 to 13-4 receive digital signals sent from the D/A converter 10 in parallel, and the digital signals are sent to the digital filters 14-1 to 14-4 after being subjected to down-conversion processing; the digital filters 14-1 to 14-4 filter the input signals, and the filtered signals are respectively sent to the timing extractors 16-1 to 16-4 to extract timing signals; each path of filtered signal and the timing signal corresponding to the filtered signal are sent to a corresponding coherent detector to obtain a corresponding demodulation signal; then, the demodulated signal is sent to a frame header and channel identifier 17 to identify a rate code and a receiving channel number; finally, the identified rate code and the receiving channel number are sent to the signal gating device 18 together with the timing signal, and the corresponding demodulation information is gated in the signal gating device 18 and sent to the decoder 8.
The simple working principle of the meteor trail autonomous frequency-changing burst modulation-demodulation device is as follows:
under the condition that a sending end sends service information, an encoder 2 and a modulator 3 output an input signal from an input port A to a D/A converter after framing processing, encoding and modulation are carried out on the input signal under the control of a main frequency-changing protocol controller 1; under the condition of sending frequency change information, the autonomous frequency change protocol controller 1 frames the frequency information to be sent, sends the frequency information to the encoder 2 and the modulator 3 to be encoded and modulated, and then outputs the encoded and modulated frequency information to the D/A converter; the D/A converter completes digital-to-analog conversion and then sends the digital-to-analog conversion to the band-pass filter 5 for filtering and then sends the digital-to-analog conversion to the output port B.
The receiving end inputs the signal of the input port D into the gain amplifier 11 to gain and amplify and then sends to the A/D converter 10, and sends to the multichannel parallel demodulator 9 after completing the digital-to-analog conversion, the multichannel parallel demodulator 9 can receive the service information and the frequency change information, and gates the corresponding demodulation information to the autonomous frequency change protocol controller 1 after identifying the frame head and the channel number, the autonomous frequency change protocol controller 1 can identify the service information and the frequency change information through the demodulation information, if the service information is, the service information is processed and then sent to the output port E, if the frequency change information is, the framing is carried out and then sent to the encoder 2 and the modulator 3.
The autonomous frequency change protocol controller 1 may initiate the frequency change mode by evaluating the current communication situation. After the frequency change is started, the receiving end sends the signal of the input port C to the sweep frequency detector 7, the sweep frequency detector 7 sends the receiving level signal to the autonomous frequency change monitor 6, and the autonomous frequency change monitor 6 sends the optimal frequency change frequency information to the autonomous frequency change protocol controller 1 through comparison.
The circuit shown in fig. 1 and 2 can be mounted on two printed boards with length × width of 180 × 150 mm, the printed boards are mounted with cable sockets connected with the external signal port A, B, C, D, E, and then the two printed boards are respectively mounted in the redundant terminal equipment chassis, so that the device can be assembled.
The invention adopts an autonomous frequency changing mode, and autonomously switches to the optimal working frequency to establish connection without the help of instruments and human intervention when a link is opened. In the communication process, if the working frequency is interfered to influence the communication effect, the working frequency is automatically switched, and the anti-interference capability and the transmission reliability of the system are improved.
In conclusion, the invention is a meteor trail modulation and demodulation device with strong anti-interference capability, and is particularly suitable for meteor trail communication of strong burstiness and fading channels.
Claims (2)
1. A meteor trail autonomous frequency-changing burst modulation-demodulation device is characterized in that according to the electromagnetic environment and communication performance of a station, the receiving frequency is autonomously changed into the working frequency with the minimum local interference, and the anti-interference capability of a system is enhanced; the device comprises a D/A converter (4), a band-pass filter (5), a sweep frequency detector (7), an A/D converter (10), a gain amplifier (11), a power supply (12) and an FPGA (field programmable gate array), wherein the FPGA is used for realizing an autonomous frequency-changing protocol controller (1), an encoder (2), a modulator (3), an autonomous frequency-changing monitor (6), a decoder (8) and a multi-channel parallel demodulator (9);
the automatic frequency-changing protocol controller (1) performs framing processing on service data input by an external port A and then sends the framed service data and control information to the encoder (2); the encoder encodes the information and then sends the information to the modulator (3); the modulator (3) modulates input data and outputs the modulated input data to the D/A converter (4); the D/A converter (4) converts the modulation signal into an analog signal and outputs the analog signal to the band-pass filter (5); the band-pass filter (5) filters the input signal and outputs the filtered signal to the outside through an output port B; the sweep frequency detector (7) detects the receiving level of each frequency point in the communication frequency band through an external input port C and sends the receiving level to the automatic frequency changing monitor (6); the autonomous frequency-changing monitor (6) obtains the optimal receiving frequency by comparing the receiving level value and sends the optimal receiving frequency to the autonomous frequency-changing protocol controller (1); the autonomous frequency-changing protocol controller (1) determines whether frequency changing is needed or not by evaluating the current communication condition, and if a signal is not received for a long time, the current communication effect is considered to be poor and the frequency changing is needed; when the frequency is changed, the frequency point information is framed and sent to the modulator (3), and then the frequency point information is output through the output port B after passing through the D/A converter (4) and the band-pass filter (5); the gain amplifier (11) receives the intermediate frequency signal through an external input port D, performs gain control on the received signal, stabilizes an output signal and sends the output signal to the A/D converter (10); the A/D converter (10) converts the analog signal into a digital signal and sends the digital signal to the multi-channel parallel demodulator (9); the multichannel parallel demodulator (9) carries out down-conversion, filtering and coherent demodulation on the signals, identifies the speed type and the channel number from the demodulated data, then sends the demodulated data to the decoder (8) for decoding, and sends the decoded data to the autonomous frequency-changing protocol controller (1); the autonomous frequency-changing protocol controller (1) identifies the decoded data, if the decoded data is service information, the service information is processed and then sent to an output port E, and if the decoded data is frequency-changing information, the frequency-changing information is sent to a modulator (3) to complete frequency change.
2. The meteor trail autonomous frequency-changing burst modem device according to claim 1, wherein said multichannel parallel demodulator (9) comprises N digital down-converters, N digital filters, N coherent detectors, N timing extractors, frame header and channel identifier (17) and signal gate (18), N ≧ 2;
the N digital down converters receive the digital signals sent from the A/D converter (10) in parallel, and respectively send the digital signals to the N digital filters after down-conversion processing; n digital filters filter input signals, and the filtered signals are respectively sent to N timing extractors to extract timing signals; each path of filtered signal and the timing signal corresponding to the filtered signal are sent to a corresponding coherent detector to obtain a corresponding demodulation signal; then, the demodulation signal is sent to a frame header and channel identifier (17) to identify a speed code and a receiving channel number; finally, the identified rate code and the received channel number are fed into a signal gate (18) together with the timing signal, and the corresponding demodulation information is gated in the signal gate (18) and fed into a decoder (8).
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