CN201985872U - Inter-cut preventing system for digital satellite broadcast transmission - Google Patents
Inter-cut preventing system for digital satellite broadcast transmission Download PDFInfo
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- CN201985872U CN201985872U CN2011200452161U CN201120045216U CN201985872U CN 201985872 U CN201985872 U CN 201985872U CN 2011200452161 U CN2011200452161 U CN 2011200452161U CN 201120045216 U CN201120045216 U CN 201120045216U CN 201985872 U CN201985872 U CN 201985872U
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Abstract
An inter-cut preventing system for digital satellite broadcast transmission comprises transmitting terminal equipment and receiving terminal equipment. In the transmitting terminal equipment, encryption signals generated by an encryption signal generator are modulated by a signal modulator into carrier wave with the frequency above 16kHZ, receives bandpass filtering from a first bandpass filter, is superimposed with external digital program signals subjected to bandstop filtering by a signal superimposer, and is transmitted by a satellite transmitter. In the receiving end equipment, superposed signals outputted by a satellite receiver sequentially pass through a second bandpass filter and is extracted and restored into encryption data of the corresponding frequency band by the signal modulator, and whether the encryption data is in accordance with reference encryption signals or not is identified and judged by a signal encryption and identification unit; and the judgment result is output to a switching control unit for outputting or program signals from the satellite receiver are cut off. By adopting the system, on the premise that a subjective listening effect is not obviously affected, various malicious interference and illegal inter-cuts can be effectively resisted, the pressure and the cost in manual monitoring can be reduced, and a security system for broadcasting safe operation can be perfected.
Description
Technical field
The utility model relates to the anti-cut system of a kind of encryption identification, specifically, relates to a kind of anti-cut system that is applied to the digital satellite broadcasting transmission.
Background technology
Since China's broadcast TV program was transmitting digitized, synchronous frequency-modulating broadcast network had been set up in most of provincial of the whole nation.Frequency modulation covers point and all adopts satellite received signal as the program signal source, in case satellite uplink is under attack, uses the frequency modulation of satellite-signal to cover the direct inevitably illegal sound that broadcasts of naming a person for a particular job; Secondly, near if the interference source of lawless person's temporary erection satellite band frequency modulation covers point, as long as the interference source parameter conforms to the satellite parametric reduction in program signal source, and signal strength signal intensity is enough, then illegal signals was covered normal satellite-signal, be easy to reception antenna reception via satellite and enter the emission system that frequency modulation covers point, broadcast illegal programs therefrom; Once more, invade unattended transmitter room, utilize the illegal signals source that carries to replace the signal source of satellite receiver output, also can realize easily illegally intercutting as the lawless person.
Since two thousand two, China satellite broadcasting television system repeatedly is subjected to the illegal signals malicious interference, and firing area comprises that prosperous promise satellite, Asia-Pacific, Asia the satellite that is loaded with domestic up broadcast TV program such as defend; Attack pattern comprises single carrier, modulated carrier, single frequency, frequency sweep mode or the like.Attack has caused serious consequence, causes social common concern.
At this situation, China expert has proposed some satellite interference protection measures, mainly contains: the signal pressure method for making that increases normal program signal ascending power; The spatial separation method that satellite adopts up fixedly shaped-beam to receive; When receiving interference signal, satellite changes the frequency isolation method of upward signal frequency; Plus signal processing unit before satellite earth station is up, satellite ground receives the signal processing method of carrying out the authentication of program source legitimacy.
At present, mainly bear satellites such as No. three, prosperous promise transmitting the home broadcasting TV programme, culminant star 6B and just taking relevant interference protection measures such as spatial separation technology, can be to a certain extent the satellite uplink of specific region be disturbed and isolate, but can't take precautions against local malicious interference and illegally intercut.
So far,, do not have with anti-and intercut the report that commercial operation was researched and developed successfully or dropped into to relevant ground installation, prevent that intercutting work is mainly realized by relevant unit's manual monitoring in the field of broadcast televisions of using satellite-signal as program source.
Summary of the invention
The purpose of this utility model provides the anti-cut system of a kind of digital satellite broadcasting transmission, and recognition technology can effectively be resisted satellite and local malice is intercutted behavior by encrypting, and effectively avoids broadcast program to suffer malicious interference and illegally intercuts.
In order to achieve the above object, the technical scheme taked of the utility model is as follows.
The anti-cut system of the utility model digital satellite broadcasting transmission comprises transmitting end equipment and receiving device.
Described transmitting end equipment comprises the coded signal generator and is connected to the band stop filter of outside program signal source, the signal modulator that is connected with the coded signal generator, first band pass filter that is connected with signal modulator, the signal superimposer that is connected with the first band pass filter output with described band stop filter respectively, the output of signal superimposer is connected to satellite launch vehicle; Wherein, the carrier frequency in the described signal modulator is more than the 16kHz, the corresponding respectively frequency range that is set to carrier frequency place in the signal modulator of the passband of the stopband of described band stop filter and first band pass filter.
Described receiving device comprises second band pass filter and the switch control unit that connects the satellite receiver output respectively, the demodulator of PM signal PM that is connected with second band pass filter, the decrypted signal recognition unit that is connected with demodulator of PM signal PM, the output of decrypted signal recognition unit is connected to the input control end of described switch control unit, and output of control switch control unit or cut-out are from the programme signal of satellite receiver; Wherein, the passband of described second band pass filter is set to the frequency range at the carrier frequency place of signal modulator in the described transmitting end equipment, be preset with synchronously in the described decrypted signal recognition unit with transmitting end equipment in the identical reference signal of coded signal that produces of coded signal generator.
Further, in the described transmitting end equipment, the carrier frequency in the signal modulator is 18kHz ~ 19kHz.
Described transmitting end equipment also comprises AES decoding unit and AES coding unit, and described outside program signal source is connected to described band stop filter by the AES decoding unit, and the output of described signal superimposer is connected to satellite launch vehicle by the AES coding unit; Described receiving device comprises the AES decoding unit, and described satellite receiver is connected respectively to second band pass filter and switch control unit by the AES decoding unit.
Described transmitting end equipment also comprises energy control module, and the described band stop filter and first band pass filter are connected to the signal superimposer by energy control module respectively.
Described transmitting end equipment also comprises data buffer, and described band stop filter is connected to the signal superimposer by energy control module and data buffer successively.
In the described transmitting end equipment, the signal modulator modulation system is ASK or FSK or DPSK.
In the described receiving device, the decrypted signal recognition unit comprises the synchronous circuit that coded signal is carried out the frame head location, the comparator by turn that is connected with the synchronous circuit output, the accumulator register that is connected with comparator output terminal by turn, the judgement comparator that is connected with accumulator register, the output of judgement comparator is connected to described switch control unit, is preset with the coded signal as reference signal in the described comparator by turn, is preset with decision threshold in the described judgement comparator.
Judgement comparator output terminal in the described decrypted signal recognition unit is also connected to the clear terminal of described accumulator register.
In the described receiving device, corresponding respectively warning information output unit, the program audio output unit of connecting of the output of switch control unit.
Described program audio output unit comprises digital audio output unit and analogue audio frequency output unit.
According to the acoustic characteristic of human body, people's ear is difficult to differentiate to the sound of frequency more than 16kHz, especially person in middle and old age colony.Based on above characteristic, (18kHz in 20～20kHz) ~ 19kHz part is inserted the continuous coded signal of waveform to the anti-cut system of the utility model in real time in the programme signal source of needs broadcasting, and rationally control its amplitude, can not produce obvious influence to subjective audibility, and can resist the MPEG-2 lossy compression method, every technical indicator all can meet the demands, and covers point at frequency modulation and differentiates the broadcast program legitimacy according to inserting signal.
The advantage of the anti-cut system of the utility model is as follows.
As above-mentioned structure, the anti-cut system of the utility model digital satellite broadcasting transmission is modulated to coded signal on the frequency that does not influence the program audibility in transmitting end equipment and mixes stack with programme signal, and in receiving device, extract this coded signal of identification, whether control the broadcast program signal.Pass through native system, can can not produce under the prerequisite of obvious influence subjective audibility, effectively resist in the satellite uplink stage attack, frequency modulation covers near the temporary erection interference source point and attacks, directly invades the various malicious interference that illegal means such as unmanned transmitter room replacement satellite signal source causes and illegally intercut.Can reduce manual supervisory pressure and cost greatly, improve broadcast safe operational support system.
Description of drawings
Fig. 1 is the structural representation of transmitting end equipment in the anti-cut system of the utility model.
Fig. 2 is the structural representation of receiving device in the anti-cut system of the utility model.
Fig. 3 is the schematic diagram of the realization signal identifying of decrypted signal recognition unit in the anti-cut system of the utility model.
Embodiment
Further specify the essential characteristic and concrete enforcement of the anti-inserting method of the utility model below in conjunction with embodiment.
Referring to Fig. 1, shown in Figure 2, the anti-cut system of the utility model digital satellite broadcasting transmission comprises transmitting end equipment 1 and receiving device 2.
Described transmitting end equipment 1 comprises coded signal generator 11 and is connected to the band stop filter 12 of outside program signal source, the signal modulator 13 that is connected with coded signal generator 11, first band pass filter 14 that is connected with signal modulator 13, the signal superimposer 15 that is connected with first band pass filter, 14 outputs with described band stop filter 12 respectively, the output of signal superimposer 15 is connected to satellite launch vehicle 3; Wherein, the carrier frequency in the described signal modulator 13 is more than the 16kHz, the corresponding respectively frequency range that is set to carrier frequency place in the signal modulator 13 of the passband of the stopband of described band stop filter 12 and first band pass filter 14.
Described receiving device 2 comprises second band pass filter 21 and the switch control unit 22 that connects satellite receiver 4 outputs respectively, the demodulator of PM signal PM 23 that is connected with second band pass filter 21, the decrypted signal recognition unit 24 that is connected with demodulator of PM signal PM 23, the output of decrypted signal recognition unit 24 is connected to the input control end of described switch control unit 22, and 22 outputs of control switch control unit or cut-out are from the programme signal of satellite receiver 4; Wherein, the passband of described second band pass filter 21 is set to the frequency range at the carrier frequency place of signal modulator 13 in the described transmitting end equipment 1, be preset with synchronously in the described decrypted signal recognition unit 24 with transmitting end equipment 1 in the identical reference signal of coded signal that produces of coded signal generator 11.
Further, for after signal stack not the subjective audibility to former audio broadcasting program produce obviously influence, in the described transmitting end equipment 1, the carrier frequency in the signal modulator 13 is 18kHz ~ 19kHz.
In the present embodiment, choose two frequencies of 18.1875kHz and 18.5625kHz in the described signal modulator 13, adopt the 2FSK modulation system, finish the modulation of coded signal.Modulation system can adopt ASK commonly used or FSK or DPSK mode, also can adopt other digital signal modulation modes as required.
In the present embodiment, described first band pass filter 14, second band pass filter 21 all adopt 200 rank Direct-Form FIR digital band-pass filters of Kai Ze-Bei Saier window, this digital band-pass filter design sample rate is 48K, the passband of described first band pass filter 14 is set to 18kHz ~ 19kHz, the passband of second band pass filter 21 is set to 18kHz ~ 18.75kHz, the stopband attenuation of two filter
Get 50,
Get 4.5, stopband attenuation is more than 50db.
In the present embodiment, described band stop filter 12 adopts 220 rank Direct-Form FIR digital band-reject filters of Kai Ze-Bei Saier window, and this digital band-reject filter design sample rate is 48K, and stopband is 18.4kHz ~ 18.72kHz, wherein stopband attenuation
Get 50,
Get 4.5, stopband attenuation more than 50db, thereby the frequency range that is inserted into coded signal in the digital program signal is suppressed.
Because the form record transmission of AES audio code stream is adopted in existing digital broadcast programme signal source usually, therefore, for being converted to synchronously, the AES audio code stream is convenient to the required pcm stream of subsequent treatment, described transmitting end equipment 1 also comprises AES decoding unit 16 and AES coding unit 17, described outside program signal source is connected to described band stop filter 12 by AES decoding unit 16, and the output of described signal superimposer 15 converts pcm stream to the AES code stream by AES coding unit 17 and is sent to satellite launch vehicle 3.Corresponding, described receiving device 2 comprises AES decoding unit 25, the AES code stream of described satellite receiver 4 outputs converts pcm stream to by AES decoding unit 25, is connected respectively to second band pass filter 21 and switch control unit 22 again.
Further, described transmitting end equipment 1 also comprises energy control module 18 and data buffer 19, described first band pass filter 14 is connected to signal superimposer 15 by energy control module 18, and described band stop filter 12 is connected to signal superimposer 15 by energy control module 18 and data buffer 19 successively.
In the present embodiment, described energy control module 18 adopts the CPLD programming device EPM570T100C5 of ALTERA company to realize, pass through EPM570T100C5, write corresponding VHDL program, calculate the instantaneous energy of programme signal and coded signal, and according to result of calculation, both energy proportions of real-time regulated are to reach the purpose of smooth signal output.
In the present embodiment, described data buffer 19 adopts the FIFO(first in first out) buffer, the digital audio and video signals behind the bandreject filtering is stored buffering, buffer depth with can and amplitude limit after the enciphered message locking phase add and be as the criterion.The fifo buffer that adopts in present embodiment, also can adopt SDRAM, memory devices such as shift register are as the data buffer in the utility model 19.
Referring to shown in Figure 3, in the described receiving device 2, decrypted signal recognition unit 24 comprises the synchronous circuit 241 that coded signal is carried out the frame head location, the comparator by turn 242 that is connected with synchronous circuit 241 outputs, the accumulator register 243 that is connected with comparator 242 outputs by turn, the judgement comparator 244 that is connected with accumulator register 243, the output of judgement comparator 244 is connected to described switch control unit 22, be preset with coded signal in the described comparator by turn 242, be preset with decision threshold in the described judgement comparator 244 as reference signal.
Further, judgement comparator 244 outputs in the described decrypted signal recognition unit 24 are also connected to the clear terminal of described accumulator register 243.
In the present embodiment, described decrypted signal recognition unit 24 adopts the dsp chip TMS320VC5409 of TI company to cooperate the CPLD chip EPM240T100C5 of ALTERA company to finish corresponding function.Wherein, TMS320VC5409 finishes the design of digital synchronous circuits, realizes the synchronous seizure of reduction scrambled data frame, and storage original encryption Frame and the required judging threshold of judgement comparator, calls for EPM240T100C5.EPM240T100C5 finishes comparator, judgement comparator by turn according to original encryption Frame and reduction scrambled data frame, judging threshold that dsp chip provides, the design of accumulator register, and produce corresponding control signal, generate court verdict and export.
In the described receiving device 2, corresponding respectively warning information output unit 221, the program audio output unit of connecting of the output of switch control unit 22.
Described program audio output unit comprises digital audio output unit 222 and analogue audio frequency output unit 223.By a D/A converting circuit 224 digital signal being converted to analog signal in the described analogue audio frequency output unit 223 exports again.
In the above-described embodiments, the anti-cut system of the utility model is made up of a plurality of physical modules, and each module is responsible for part of functions, works alone, and has realized that the classification of data is handled.It promptly is the complete anti-cut system of digital satellite broadcasting signal transmission that these physical modules combine.
During work, transmitting terminal in the anti-cut system of the utility model: by coded signal generator 11 input original encryption signals, in the signal modulator 13 the original encryption signal is modulated on selected one or more frequencies and (chooses two frequencies of 18.1875kHz and 18.5625kHz in the present embodiment), and carry out the 18K-19K bandpass filtering by the coded signal after 14 pairs of modulation of first band pass filter, carry out spuious inhibition.
On the other hand, the digital broadcast program signal of AES audio code stream form converts pcm stream to by AES decoding unit 16, and is carried out the bandreject filtering of 18kHz ~ 18.75kHz by 12 pairs of digital audio and video signals of band stop filter.
Coded signal and programme signal that first band pass filter 14 and band stop filter 12 are exported respectively enter energy control module 18, energy control module 18 is calculated the energy of programme signal in real time, and adjust the energy of coded signal according to the programme signal energy, make both keep proper proportion, ensure the program audibility.Except that the aforesaid way that present embodiment adopts, also can adjust the energy of programme signal, reach effect same.
Enter data buffer 19 by the programme signal of energy control module 18 output and store buffering, with the programme signal after guaranteeing to cushion can with the synchronous addition of coded signal through exporting after the energy adjustment.The programme signal and the coded signal of buffering superposes in signal superimposer 15 (adopting the direct addition of signal in the present embodiment), if the signal amplitude after the stack surpasses the amplitude upper limit of adder, then cuts the top and handles, be i.e. overflow protection.
The coded signal of signal superimposer 15 outputs and the superposed signal of programme signal convert the AES code stream to again by AES coding unit 17, and are sent to satellite launch vehicle 3, and emission is broadcast TV programs by satellite.
Receiving terminal in the anti-cut system of the utility model: the AES code stream decoding of 25 pairs of satellite receivers of AES decoding unit, 4 outputs is converted to pcm stream, and decoded signal outputs to second band pass filter 21 and switch control unit 22 respectively.
Band pass filter carries out bandpass filtering to decoded signal, extract the data of coded signal place frequency range, and be transferred to demodulator of PM signal PM 23, the data of extracting are carried out the 2FSK demodulation, restore the scrambled data frame that comprises the original encryption signal, output to decrypted signal recognition unit 24.
In the decrypted signal recognition unit 24, synchronous circuit 241 at first carries out the frame head location to the scrambled data frame that restores, by comparator 242 by turn the scrambled data frame that restores and normal data frame as reference signal are compared by turn then, and for example deposit comparative result in accumulator register 243(, if current relatively position is identical, data in the accumulator register+1 then), at last when frame data are relatively finished, the default decision threshold of judgement comparator 244 bases is determined comparative result, comparative result is exported to signal switch control unit 22, and pass through clear terminal (CLR) with the data zero clearing in the accumulator register 243, enter next recognition cycle.
Signal switch control unit 22 is determined the legitimacy of received signal in real time, and is switched to corresponding output signal according to the comparison result and the predefined judgement number of times of 24 outputs of decrypted signal recognition unit.If received signal is illegal, then control signal outputs to warning information output unit 221, the outputting alarm signal; If received signal is legal, then will export to the program audio output unit from the programme signal of AES decoding unit 25, by digital audio output unit 222 and analogue audio frequency output unit 223 difference outputting digital audio programme signal and analogue audio frequency programme signals, broadcast by upstream device.
Claims (10)
1. the anti-cut system of digital satellite broadcasting transmission comprises transmitting end equipment and receiving device, it is characterized in that:
Described transmitting end equipment comprises the coded signal generator and is connected to the band stop filter of outside program signal source, the signal modulator that is connected with the coded signal generator, first band pass filter that is connected with signal modulator, the signal superimposer that is connected with the first band pass filter output with described band stop filter respectively, the output of signal superimposer is connected to satellite launch vehicle; Wherein, the carrier frequency in the described signal modulator is more than the 16kHz, the corresponding respectively frequency range that is set to carrier frequency place in the signal modulator of the passband of the stopband of described band stop filter and first band pass filter;
Described receiving device comprises second band pass filter and the switch control unit that connects the satellite receiver output respectively, the demodulator of PM signal PM that is connected with second band pass filter, the decrypted signal recognition unit that is connected with demodulator of PM signal PM, the output of decrypted signal recognition unit is connected to the input control end of described switch control unit, and output of control switch control unit or cut-out are from the programme signal of satellite receiver; Wherein, the passband of described second band pass filter is set to the frequency range at carrier frequency place in the signal modulator of described transmitting end equipment, be preset with synchronously in the described decrypted signal recognition unit with transmitting end equipment in the identical reference signal of coded signal that produces of coded signal generator.
2. the anti-cut system of digital satellite broadcasting transmission as claimed in claim 1 is characterized in that in the described transmitting end equipment, the carrier frequency in the signal modulator is 18kHz ~ 19kHz.
3. the anti-cut system of digital satellite broadcasting transmission as claimed in claim 1, it is characterized in that, described transmitting end equipment also comprises AES decoding unit and AES coding unit, described outside program signal source is connected to described band stop filter by the AES decoding unit, and the output of described signal superimposer is connected to satellite launch vehicle by the AES coding unit; Described receiving device comprises the AES decoding unit, and described satellite receiver is connected respectively to second band pass filter and switch control unit by the AES decoding unit.
4. the anti-cut system of digital satellite broadcasting transmission as claimed in claim 1 is characterized in that described transmitting end equipment also comprises energy control module, and the described band stop filter and first band pass filter are connected to the signal superimposer by energy control module respectively.
5. the anti-cut system of digital satellite broadcasting transmission as claimed in claim 4 is characterized in that described transmitting end equipment also comprises data buffer, and described band stop filter is connected to the signal superimposer by energy control module and data buffer successively.
6. the anti-cut system of digital satellite broadcasting transmission as claimed in claim 1 is characterized in that in the described transmitting end equipment, the signal modulator modulation system is ASK or FSK or DPSK.
7. the anti-cut system of digital satellite broadcasting transmission as claimed in claim 1, it is characterized in that, in the described receiving device, the decrypted signal recognition unit comprises the synchronous circuit that coded signal is carried out the frame head location, the comparator by turn that is connected with the synchronous circuit output, the accumulator register that is connected with comparator output terminal by turn, the judgement comparator that is connected with accumulator register, the output of judgement comparator is connected to described switch control unit, be preset with coded signal in the described comparator by turn, be preset with decision threshold in the described judgement comparator as reference signal.
8. the anti-cut system of digital satellite broadcasting transmission as claimed in claim 7 is characterized in that the judgement comparator output terminal in the described decrypted signal recognition unit is also connected to the clear terminal of described accumulator register.
9. the anti-cut system of digital satellite broadcasting transmission as claimed in claim 1 is characterized in that, in the described receiving device, and corresponding respectively warning information output unit, the program audio output unit of connecting of the output of switch control unit.
10. the anti-cut system of digital satellite broadcasting transmission as claimed in claim 8 is characterized in that described program audio output unit comprises digital audio output unit and analogue audio frequency output unit.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011200452161U CN201985872U (en) | 2011-02-23 | 2011-02-23 | Inter-cut preventing system for digital satellite broadcast transmission |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011200452161U CN201985872U (en) | 2011-02-23 | 2011-02-23 | Inter-cut preventing system for digital satellite broadcast transmission |
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| Publication Number | Publication Date |
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| CN201985872U true CN201985872U (en) | 2011-09-21 |
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| CN2011200452161U Expired - Fee Related CN201985872U (en) | 2011-02-23 | 2011-02-23 | Inter-cut preventing system for digital satellite broadcast transmission |
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| CN (1) | CN201985872U (en) |
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2011
- 2011-02-23 CN CN2011200452161U patent/CN201985872U/en not_active Expired - Fee Related
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