CN103856242B - Power line communication countermeasure set - Google Patents

Power line communication countermeasure set Download PDF

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CN103856242B
CN103856242B CN201210500190.4A CN201210500190A CN103856242B CN 103856242 B CN103856242 B CN 103856242B CN 201210500190 A CN201210500190 A CN 201210500190A CN 103856242 B CN103856242 B CN 103856242B
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power line
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power
interference
communication
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CN103856242A (en
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陈莉华
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Abstract

The present invention relates to power line communication countermeasure set, particularly relating to the multiple device to utilizing the facility of power line communication to carry out Communication Jamming, belonging to power line communication, Communication Jamming and anti-interference, field of information security technology.Specifically comprise power line interface, DC power supply, power line couples filter, power amplifier and interference signal generator; Also provide a kind of and there is the power line communication countermeasure set of electric-power wire communication signal determination and analysis function, a kind of processing forward type power line communication countermeasure set, and the power line communication countermeasure set of a kind of electric-power wire communication signal short circuit/bypass.The present invention easily by power line interference device access power line, produces the interference signal of interference power line communication by forms such as power line socket, slot and sockets; Reach good interference effect by extremely low interference power, power consumption is low, is particularly suitable for the interference application of low-power consumption; Jammer structure is simple, it is low to realize cost, and adaptive ability is strong.

Description

Power line communication countermeasure set
Technical field
The present invention relates to power line communication countermeasure set, particularly relating to the device that the multiple facility to utilizing power line to communicate carries out Communication Jamming, belonging to power line communication, Communication Jamming and anti-interference, field of information security technology.
Background technology
Power line carrier communication is a kind of technology adopting power line transmission signal of communication to realize information transmission.Communication signal process system adopts power line couples filter to be connected to power line, realizes transmission and the reception of signal of communication.The forceful electric power that power line couples filter realizes communication system and power line is isolated, and by the transmission signal coupling of communication system to power line settling signal to the output of power line; Meanwhile, this filter by coupling communication signals that power line transmits to communication system, the input of settling signal from power line to communication system.Power line couples filter can adopt electromagnetic coupled, resistance-capacitance coupling, electromagnetism resistance-capacitance coupling, electromagnetism capacitance-resistance in conjunction with the technology such as compound coupling of opto-electronic conversion and electro-optic conversion, realizes the coupling communication signals of various different passband bandwidth.Such as, the paper of Zeng Suqiong on " low-voltage electrical apparatus " of the 20th phase in 2010 " the low-voltage powerline carrier communication interface circuit design based on compound coupling technique " gives the power line couples filter that a kind of electromagnetic coupled as shown in Figure 1 and resistance-capacitance coupling combine.Wherein Trans4 is resonance transformer, and L represents inductance, and C represents electric capacity, and R represents resistance, and the value of each element is shown in figure.According to the calculating of Authors of Science Articles, this power line couples filter can power line be carried on change within the scope of 5 ~ 15 ohm time, realize passband (signal attenuation is less than the frequency band range of 3dB) within the scope of 60kHz-132.5kHZ and to send and Received signal strength is coupled.At present, for realizing power line carrier communication, the power line couples filter connecting power line and power line communications apparatus has a lot of ripe product.Such as, the MCD80 filter of ABB AB is exactly that one wherein can support that high-power signal sends, and can provide band logical or high-pass filtering characteristic, the programmable power line couples filter of bandwidth.But the general volume of this product-level filter joint is larger.For reducing the volume of power line communications apparatus, can electric circuit grade design be adopted, power line filter joint is embedded into power line communications apparatus inside and complete corresponding function.
Along with the development of power line communication technology, power line standard is as ripe and perfect gradually in IEEEP1901 etc.At present, the technology adopting power line to carry out communicating is commercial.Such as, support that the power line communication modem (also known as " Homeplug ") of the various traffic rates such as 14Mbps, 22Mbps, 85Mbps, 200Mbps and 500Mbps is comparatively common.Estimate that traffic rate reaches the Homeplug of the even several Gbps of 1Gbps by commercialization in the near future.Use the modulator-demodulator based on power line communication, the power line network of family or office can be become cable LAN by people quickly and easily, neither affects original electric power transfer, achieves again communication at a high speed; Carry out communicating and adopting radio communication net to compare based on cable network, also there is the advantage not producing electromagnetic radiation pollution.Power line communication is adopted to bring very large convenience to the life and work of people.
Adopt power line to carry out communication information transmission to bring more convenient.But meanwhile, adopt power line to carry out the convenient and swift of communication information transmission and also may bring certain potential safety hazard to the information security of people.The integral system of a kind of multicomponent signal sample and transform, monitoring and power line communication is given in the patent application of " a kind of power communication integral system of multiple information sample and transform " (numbering 201210455304.8 and 20120450857.4).Apply this system, camera, the transducer of the mechanical interface band power line communication function similar to illuminating lamp with profile can be accessed on the lamp socket of illuminating lamp, the data that camera or transducer are collected after power line transmission by gateway interface accessing Internet, being sent to monitor supervision platform local arbitrarily for reading, carrying out information gathering, transmission and monitoring management to people and bringing conveniently.If but this method can bring certain information security hidden danger to user for invalid information acquisition.The individual privacy of people, the technical data of company are probably stolen when not easily discovering.First, because the signal picker of electrical equipment and band power line communication function has integral structure, can be arranged on lamp socket, power line socket, slot or socket, profile is similar to ordinary appliances, is difficult to discover; Secondly, the audio frequency and video of band power line communication function and the volume of transducing signal collector may be very little, are difficult to find; In addition, power line communication is a kind of wire communication mode, and radiated electromagnetic wave is very faint, cannot wirelessly disturb.
Prevent the effective ways being carried out invalid information transmission by power line from being carry out Communication Jamming.Have at present and radio interference or wired electrical interference mode are comprised to the interference that telecommunication carries out.Power line communication is a kind of electrical communication mode, low pressure and indoor power line also have protection insulating barrier, adopt wireless system to disturb it, the power that interference signal is wirelessly coupled into power line is very faint, will be difficult to play effective interference effect.Existing wired jamming equipment also cannot disturb power line communication, because power line transmits forceful electric power, and existing wire communication jamming equipment is weak current equipment, directly cannot be connected with power line; Secondly, the frequency band of these equipment interference signals does not meet the signal passband that power line carries out communicating, and is difficult to realize effective interference.
Summary of the invention
The object of the invention is to transmission medium power line transferring electric power and the signal of communication simultaneously for power line communication, existing wired shortcoming all effectively cannot disturbed its enforcement with radio communication device, give the multiple device form disturbed power line communication.
A kind of power line communication countermeasure set, comprises power line interface, DC power supply, power line couples filter, power amplifier and interference signal generator.Wherein, interference signal generator exports and is connected to power amplifier; Power amplifier exports and is connected to power line couples filter; Power line couples filter, DC power supply are connected with power line interface respectively; DC power supply is connected with interference signal generator, power amplifier.
Described DC power supply obtains electric energy from power line interface, and power frequency civil power is converted to low-voltage DC, for power amplifier and interference signal generator are powered.
Described power line interface provides the interface with power line; By socket, slot and socket type, by interference signal input power line.
Described power line couples filter completes the isolation of forceful electric power and light current, overvoltage and overcurrent protection, interference and exports the high pass of passband or bandpass filtering and the signal coupling that exported by power amplifier to power line, realizes power line transmission channel and the impedance matching disturbing output.
Interference signal needed for described interference signal generator produces.
Described power amplifier completes the power amplification of interference signal.
Described interference signal generator adopts single-frequency signal generator, or bandpass-type white Gaussian noise interference unit, or arrowband type white Gaussian noise interference unit, or white Gaussian noise frequency-modulated jammer, or Sweeping nonlinearity device, or random waveform frequency-modulated jammer.Wherein, bandpass-type white Gaussian noise interference unit comprises Gaussian white noise generator and band pass filter; Arrowband type white Gaussian noise interference unit comprises Gaussian white noise generator and narrow band filter; White Gaussian noise frequency-modulated jammer comprises voltage controlled oscillator, narrow band filter and Gaussian white noise generator; Sweeping nonlinearity device comprises voltage controlled oscillator and Saw-tooth Signal Waveform Generator; Random waveform frequency-modulated jammer comprises voltage controlled oscillator and AWG (Arbitrary Waveform Generator).
Described single-frequency signal generator produces simple signal, is connected to power amplifier; Carry out being input to power line by power line couples filter after power amplification through power amplifier, mono-tone interference is carried out to the power line communication receiver be connected on power line.
The band pass filter of described bandpass-type white Gaussian noise interference unit can cover more than 10% bandwidth of electric-power wire communication signal passband; Described arrowband type white Gaussian noise interference unit accounts for power line passband 10% and following bandwidth.The output of arrowband type white Gaussian noise interference unit is arrowband interference; The narrow band signal of white Gaussian noise frequency-modulated jammer, through frequency modulation, exports as broad-band interference.
Described Gaussian white noise generator produces gaussian signal, exports and is connected to band pass filter or narrow band filter; For white Gaussian noise frequency-modulated jammer, its narrow band filter exports voltage controlled oscillator to and carries out frequency modulation; The output of band pass filter or narrow band filter or voltage controlled oscillator is connected to power amplifier.Be input to power line by power line couples filter, broadband or arrowband interference are carried out to the power line communication receiver be connected on power line.
Described Saw-tooth Signal Waveform Generator produces zigzag time waveform signal, and input voltage controlled oscillator carries out frequency modulation and obtains swept-frequency signal; Voltage controlled oscillator exports and is connected to power amplifier.
Described AWG (Arbitrary Waveform Generator) connects voltage controlled oscillator and carries out frequency modulation, and its output is connected to power amplifier.
A kind of power line communication countermeasure set, also comprises electric-power wire communication signal determination and analysis device.
Described electric-power wire communication signal determination and analysis device is connected between interference signal generator and power line couples filter; Receive the signal in electric-power wire communication signal frequency band, and carry out to received signal detecting, analyzing; DC power supply is its power supply.
Described electric-power wire communication signal determination and analysis device and the interference signal generator be attached thereto adopt electric-power wire communication signal band spectrum detector and multi-band interferance generator respectively.Electric-power wire communication signal band spectrum detector receives the signal in electric-power wire communication signal frequency band, and carries out power spectrum detection to it, and according to this testing result, controls jamming pattern, jamming bandwidth and interference band quantity that interference signal produces; Multi-band interference signal needed for multi-band interferance generator produces.
Described electric-power wire communication signal determination and analysis device and the interference signal generator be attached thereto adopt power line communication pilot signal detector and Pilot Interference generator respectively.Power line communication pilot signal detector carries out extracting and analyzing based on the power line communication standard of known pilot structure and product pilot frequency information to received signal, and according to analyzing the pilot frequency mode, pilot frequency locations, the pilot length information that obtain, controlling Pilot Interference generator and producing Pilot Interference signal targetedly.
Described electric-power wire communication signal determination and analysis device and the interference signal generator be attached thereto adopt power line communication OFDM Cyclic Prefix correlation detector and Cyclic Prefix interferance generator respectively.Power line communication OFDM Cyclic Prefix correlation detector carries out extracting and analyzing based on the known electric line of force communication standard and the product information such as OFDM symbol original position, circulating prefix-length to received signal adopting OFDM modulation mode, and according to analysis result, controlled circulation prefix interferance generator produces the interference signal destroying OFDM Cyclic Prefix.
Adopt Received signal strength forwarding processor to replace the interference signal generator of described power line communication countermeasure set, obtain the processing forward type power line communication countermeasure set with processing forward electric-power wire communication signal ability.Described Received signal strength forwarding processor receives the electric-power wire communication signal through the input of power line couples filter, after the linear processes process of setting, is forwarded to power line by power amplifier, directly utilizes signal of communication frequency spectrum to form interference.
A power line communication countermeasure set for electric-power wire communication signal short circuit/bypass, comprises power line interface, electric-power wire communication signal short circuit/bypass apparatus.Electric-power wire communication signal short circuit/bypass apparatus accesses power line by power line interface.
Described power line interface provides the interface with power line; Adopt socket, slot and socket type.
Described electric-power wire communication signal short circuit/bypass apparatus is Low ESR by one to the signal in power line communication passband, is that the short circuit/bypass network of higher resistance is by signal of communication bypass to civil power power frequency, the signal of communication that power line communication receiver is received produces comparatively high attenuation, stop power line communication receiver to signal of communication demodulation, avoid alternating electromotive force short circuit and bypass, electric power is along power line normal transmission simultaneously; By adding suitable overvoltage and current foldback circuit, and choose the circuit element with resistance to compression and anti-current ability and build short circuit/bypass network, complete overvoltage and overcurrent protection.
The input impedance that power line communication countermeasure set has frequency domain characteristic is Z i(ω) power line communication countermeasure set input voltage V, is represented i(ω) with input current I i(ω) ratio, wherein, ω represents the angular frequency of input voltage or electric current.Power line communication countermeasure set is connected to power line, and the load impedance of its frequency domain characteristic is Z l(ω).Described Z l(ω) be the impedance that the two-port be connected with power line from countermeasure set is formed to power line direction, represent the party input voltage V upwards l(ω) with input current I l(ω) ratio.Load impedance Z l(ω) communication equipment impedance on electrical equipment impedance, power line, power line direct impedance and other connection in series-parallel total impedance that circuit impedance is formed on power line on power line is specially.
Electric-power wire communication signal short circuit/bypass apparatus is built according to following principle:
Circuit network built by selecting circuit element, makes this network at the alternating current power frequency ω of power line 0meet | Z i(ω 0) | > 10|Z l(ω 0) | or Z i(ω) at ω 0there is limit in place, namely this network presents higher resistance or high resistant to electric power frequency, ensures that power line power frequency electric power can not disturbed device bypass or short circuit; Meanwhile, this network is at the signal passband ω of power line communication l≤ ω≤ω hmeet in scope | Z i(ω) | < | Z l(ω) | or | Z i(ω) | < < | Z l(ω) | or Z i(ω)=0, to ensure on power line in signal of communication passband most of signal or most signal or all disturbed device bypass of signal or short circuits.Its ω land ω hbe respectively the low cut-off angular frequency of passband and high cut-off angular frequency.
Described electric-power wire communication signal short circuit/bypass apparatus; adopt electric capacity; or inductance; or electric capacity and inductance; or electric capacity and resistance, or inductance and resistance, or the short circuit/bypass network of electric capacity, inductance and resistance composition; form and the signal in power line communication passband be Low ESR, be higher resistance, have the short circuit/bypass network of over-voltage over-current protection simultaneously to electric power frequency, make | Z i(ω 0) | > 10|Z l(ω 0) |, and at ω l≤ ω≤ω hmeet in scope | Z i(ω) | < | Z l(ω) | or | Z i(ω) | < < | Z l(ω) | or Z i(ω)=0.Wherein, Z i(ω) be the input impedance of countermeasure set frequency domain characteristic, Z l(ω) be the load impedance of frequency domain characteristic.
Beneficial effect
The present invention accesses power line easily by forms such as power line socket, slot and sockets, produces the interference signal of interference power line communication; User, without the need to checking the audio frequency and video or transducing signal collecting device of whether power line having installed based on power line communication, can effectively prevent someone from using power line illegally to steal subscriber data and user's private information.Apparatus of the present invention adopt the conflicting mode of wired electricity, not to spatial emission electromagnetic wave, thus do not produce electromagnetic pollution.The present invention does not detect the signal of communication of power line communication, disturbs power line communication according to preset power line pass band, reduces equipment cost; Simultaneously can realize receiving and detect the signal of communication of power line, analyze the feature extracting electric-power wire communication signal, according to these features, interference signal is targetedly applied with to power line communication, good interference effect can be reached by extremely low interference power, power consumption is low, is particularly suitable for the interference application of low-power consumption.
The present invention also provides a kind of processing forward type interference unit, directly utilizes signal of communication frequency spectrum to form interference; The frequency band that its communication signal power density spectra is high, interference power spectrum also strengthens thereupon, and interference adaptive ability is strong; Its jammer structure is simple, it is low to realize cost, is not easy to produce interference and omits.
The countermeasure set of signal of communication short circuit/bypass type of the present invention, pure inductance and capacitance network is adopted to form signal bypass network, have good power line communication to disturb and inhibition to the power line communications apparatus be connected in parallel on power line, have that interference is efficient, structure simple, equipment cost and the low advantage of use cost.
Accompanying drawing explanation
Fig. 1 is the power line couples filter that a kind of electromagnetic coupled of prior art and resistance-capacitance coupling combine;
Fig. 2 is power line communication countermeasure set structured flowchart of the present invention;
Fig. 3 is power line communication mono-tone interference device structured flowchart of the present invention;
Fig. 4 is power line communication bandpass-type white Gaussian noise interference unit structured flowchart of the present invention; Wherein (a) is bandpass-type, and (b) is arrowband type;
Fig. 5 is power line communication white Gaussian noise frequency-modulated jammer structured flowchart of the present invention;
Fig. 6 is power line communication Sweeping nonlinearity device structured flowchart of the present invention;
Fig. 7 is power line communication random waveform frequency-modulated jammer structured flowchart of the present invention;
Fig. 8 is the apparatus structure block diagram that power line communication that the present invention has a determination and analysis function carries out disturbing;
Fig. 9 is the multi-band interference unit structured flowchart that the present invention is based on the detection of electric-power wire communication signal band spectrum;
Figure 10 is the Pilot Interference device structured flowchart that the present invention is based on power line communication pilot signal detection result;
Figure 11 is the Cyclic Prefix interferance generator structured flowchart that the present invention is based on power line OFDM modulation mode;
Figure 12 is two kinds of waveforms of random waveform frequency-modulated jammer in embodiment; Wherein (a) is random notch cuttype waveform, and (b) is random ramp type waveform;
Figure 13 is processing forward type power line communication countermeasure set of the present invention;
Figure 14 is the circuit diagram using transformer-coupled power line communication countermeasure set in embodiment; When wherein (a) is for power line couples filter and DC power supply employing parallel join, the annexation schematic diagram of countermeasure set and power line; B circuit diagram that () is countermeasure set;
Figure 15 is the circuit diagram using capacity coupled power line communication countermeasure set in embodiment; Wherein (a) for power line couples filter and DC power supply adopt connected in series time, the annexation schematic diagram of countermeasure set and power line; B circuit diagram that () is countermeasure set;
Figure 16 is electric-power wire communication signal of the present invention short circuit/bypass type countermeasure set and embodiment; A countermeasure set structured flowchart that () is electric-power wire communication signal short circuit type; B () is capacitor type short circuit/bypass apparatus; C capacitor type short circuit/bypass apparatus that () is protection with voltage; D () is L-C series resonance short circuit/bypass apparatus.
Embodiment
Below in conjunction with drawings and Examples, technical scheme of the present invention is described further and is described in detail.
A countermeasure set for power line communication, as shown in Figure 2, comprising: power line interface, DC power supply, power line couples filter, power amplifier and interference signal generator.Wherein contain in empty frame and produce the modules of interference signal, DC power supply and empty frame have dotted line to be connected to represent that DC power supply is connected with the modules in empty frame, and provide power supply for these modules.For the convenience described, unless specifically stated otherwise, in the present embodiment, the module of unit composition each in frame empty in each figure is called interferance generator; Empty frame is connected with the dotted line of DC power supply and represents and power.Power line couples filter adopts electromagnetic coupled, resistance-capacitance coupling, electromagnetism resistance-capacitance coupling, electromagnetism capacitance-resistance in conjunction with the technology such as compound coupling of opto-electronic conversion and electro-optic conversion; complete the coupling of interference signal to power line; and electric-power wire communication signal passband inband signaling is to the coupling of interference unit receiver module; realize power line to isolate with the forceful electric power of the modules producing interference signal; complete overvoltage and overcurrent protection, and complete the impedance matching that interference signal is sent to power line.
As an embodiment, adopt the power line couples filter that the electromagnetism capacitance-resistance shown in Fig. 1 combines.When power line load changes within the scope of 5 ~ 15 ohm, this coupling filter can maintain the pass band of 60kHz ~ 132.5kHz.Consider that low-voltage power line load impedance is 10 ohm, calculate and show that this filter passbands scope is 26.5kHz ~ 250kHz.Or use electromagnetic coupled power line couples filter, choose suitable inductance and capacitance, to reduce the heating because resistance causes, make filter also have passband 26.5kHz ~ 250kHz.Use electromagnetic coupled filter, avoid the heating using resistance to cause, extra power consumption can be reduced, be conducive to the power service efficiency improving countermeasure set.Interference signal generator produces 30kHz, 50kHz, 78kHz totally 3 simple signals, is sent to power line couples filter through power amplifier.Because 3 simple signals are all in the passband of power line couples filter, these mono-tone interference signals can be input to power line, disturb the power line communications apparatus be connected on power line.Interferance generator also can produce with the triangular pulse of single duration 20us be basic pulse periodicity or random bursty interference, this triangular pulse adopts frequency to be after the sine wave modulation of 150KHz, is input to power line couples filter after sending into power amplifier.This random burst triangular pulse interference can cover the frequency band range of 50KHz ~ 250KHz (first zero bandwidth).By sending interference signal to power line, the carrier sense mechanisms of electric line communication system, access avoidance mechanism can be destroyed, the CRC check of repeat request mechanism, data and control frame, pilot tone and synchronizing signal, reduce the signal interference ratio etc. of signal of communication, thus stop and suppress communicating on power line.
When needing to send mono-tone interference signal to the communication equipment on power line, adopt the mono-tone interference device shown in Fig. 3.This interference unit produces mono-tone interference signal, selects the frequency of mono-tone interference signal, this frequency is dropped in the pass band of power line communication.Such as this simple signal is selected near the carrier frequency of electric-power wire communication signal, and it is different with the carrier frequency of electric-power wire communication signal, because the power of interference signal is higher than electric-power wire communication signal power, the pilot synchronization system of communication signal receiver will detect the carrier frequency of mistake, cannot carrier synchronization be carried out, thus cannot correct its signal of communication of demodulation.When the power of simple signal is enough large, the communication control processor that is connected on power line can be made saturated, cannot correct receiving communication signal.
When needing to send broadband or the interference of narrowband Gaussian white noise to the passband of the communication equipment on power line, adopt the bandpass-type white Gaussian noise interference unit shown in Fig. 4, wherein scheming (a) is bandpass-type, and figure (b) is arrowband type.In the present invention, if the bandwidth of band pass filter covers more than 10% bandwidth of electric-power wire communication signal passband, then bandpass-type is referred to as; If band pass filter accounts for power line passband 10% and following bandwidth, be referred to as arrowband type.Such as, for INT64000HomePlugAV, its pass band is 1.8MHz ~ 30MHz, and passband bandwidth is 28.2MHz.If interfering signal power concentrates in 2.8MHz or less bandwidth range, then it is arrowband interference; Being greater than within the scope of 2.8MHz if interfering signal power is distributed in, is then broad-band interference.Wideband interferer signal can disturb the signal of communication existed in very wide frequency band range, is thus not easy to produce to omit, but power dispersion is in wider frequency band, and interference power spectrum density reduces, and has certain adverse effect to the effect of interference.Adopt arrowband interference to be conducive to improving the power spectral density of interference signal, improve interference effect, but interference fringe width, if signal of communication drops on outside jamming bandwidth, then not easily disturbedly to arrive.In the jamming equipment of reality, probability can be omitted according to interference effect and interference and select conflicting mode flexibly.Such as, if the frequency band range that some conventional electric line communication systems use can be determined in advance, then can design suitable jamming bandwidth, both ensure interference effect, reduce again and omit probability.
When needing to send the interference of white Gaussian noise frequency modulation to the passband of the communication equipment on power line, adopt power line communication white Gaussian noise frequency-modulated jammer shown in Fig. 5.The white noise that Gaussian white noise generator produces becomes narrowband Gaussian noise after narrow-band filtering, and this narrowband Gaussian noise is sent into voltage controlled oscillator and completed frequency modulation.If narrowband Gaussian noise is ξ (t)=ξ c(t) cos ω 1t+ ξ s(t) sin ω 1t, wherein ξ c(t) and ξ st () is respectively in-phase component and the quadrature component of narrowband Gaussian random process ξ (t), the two is Gaussian random process, and separate.ω 1for the center angular frequency of narrow-band noise.Then voltage controlled oscillator exports and is
s 1 ( t ) = A cos ( &omega; c t + &Integral; - &infin; t K F &xi; ( &tau; ) d&tau; )
Wherein ω cfor the carrier frequency of carrier signal.The instantaneous frequency of voltage controlled oscillator output signal is ω (t)=ω c+ K fξ (t).Because ξ (t) is narrowband Gaussian random process, its value change at random in time.Such interference is unpredictable, has good anti-jamming effect.If select the bandwidth of frequency modulation index (FM index) and narrow band filter, interference signal can be made to be full of the whole passband of power line communication, form broad-band interference.In some moment, interfering signal power all concentrates on frequencies omega (t), then have very strong interference strength.Therefore, the frequency modulation interference of narrow band signal has the advantage being difficult to predict, interference fringe is wide, large to communication interference intensity.Such as, AR7400HomePlugAV pass band is 1.8MHz ~ 50MHz.Choose the narrow band filter of a Low-Pass Filter, getting its cut-off frequency is f m=1MHz; Get frequency modulation index (FM index) m f=24, then the modulated interfering signal bandwidth of voltage controlled oscillator output signal is B fM=2 (m f+ 1) f m=50MHz.Therefore, this interference can implement interference (when considering the power line couples filter of design interference unit to the whole passband of AR7400HomePlug power line communication, 1.8MHz is designed into stopband, the interference of below 1.8MHz can not send into power line, can not impact the electricity consumption of electric equipment).
When needing to send Sweeping nonlinearity to the passband of the communication equipment on power line, adopt power line communication Sweeping nonlinearity device shown in Fig. 6.The saw-toothed wave generator of this Sweeping nonlinearity device produces periodic sawtooth waveforms, i.e. m (t)=∑ ng (t-nT s), wherein t sfor sawtooth wave period.This periodic signal acts on voltage controlled oscillator, and the frequency that voltage controlled oscillator exports FM signal linearly changes with input waveform, and the frequency of its voltage controlled oscillator output signal is f (t)=f c+ K fm (t), wherein K ffor frequency modulation sensitivity.Because g (t) periodically changes linearly over time, the frequency f (t) of voltage controlled oscillator output signal also incites somebody to action in time periodically linear change, and in frequency scanning characteristic, its interference is Sweeping nonlinearity.Suitable selection frequency sweep cycle, frequency modulation sensitivity parameter K f, carrier frequency parameter, Sweeping nonlinearity device can produce the Sweeping nonlinearity signal within the scope of nominated bandwidth.Such as, the passband of IntellonHomePlugAV is 7.5MHZ ~ 65MHZ, and existing needs produces the Sweeping nonlinearity to this electric-power wire communication signal 30MHZ to 40MHZ scope, can choose carrier frequency f c=30MHZ, T s=1ms, K f=1 × 10 10.
When needs send the interference of various frequency modulation flexibly to the passband of the communication equipment on power line neatly, an AWG (Arbitrary Waveform Generator) can be used to produce waveform, send into voltage controlled oscillator and carry out frequency modulation.Give this power line communication random waveform frequency-modulated jammer as shown in Figure 7.Its AWG (Arbitrary Waveform Generator) can prestore the waveform of various modes, according to the various different waveform of these Waveform composition.Such as, AWG (Arbitrary Waveform Generator) can prestore Gaussian pulse waveforms, bell-shaped pulse, triangular pulse, block the baseband waveforms such as sine pulse, rectangular pulse, ramp pulse.If the cut-off frequency of baseband waveform is f m, frequency modulation index (FM index) is m f, then the FM signal bandwidth that voltage controlled oscillator exports is B fM=2 (m f+ 1) f m.When producing interference, in each cycle T s time range, choose a kind of baseband waveform, use one (-1, + 1) in scope, equally distributed randomizer produces random number, using the amplitude of this random number as baseband waveform, export the baseband waveform through this random number amplitude weighting.Owing to adopting random number to waveform weighting, voltage controlled oscillator output signal is stochastic behaviour, and its interference is unpredictable, has the ability that antagonism adopts interference cancellation algorithm receiver.As Figure 12 gives the random notch cuttype waveform and random ramp type waveform that can be used for producing frequency modulation interference, wherein random notch cuttype waveform can be used to produce the interference of random frequency hopping type, and random ramp type waveform can be used to produce random Sweeping nonlinearity.
A kind of power line communication with determination and analysis function carries out the device disturbed, as shown in Figure 8, comprising: power line interface, DC power supply, power line couples filter, power amplifier, interference signal generator and electric-power wire communication signal determination and analysis device.Electric-power wire communication signal determination and analysis device is received from the signal in power line communication frequency band by power line couples filter, and carries out determination and analysis to this Received signal strength; If communication standard, code modulation mode, pilot frequency mode, synchronizing signal that on power line, communication equipment uses can be identified, then can produce interference signal targetedly according to these information.Because its interference signal is pointed, very little interference power can be adopted to reach good interference effect, and its jamming effectiveness is very high.Such as, if electric-power wire communication signal determination and analysis device detects the synchronizing signal position that power line communications apparatus uses in the communications and synchronous duration, then send the disturbing pulse of short time just can make the channel estimating of communication control processor in this position and synchronously cannot carry out, realize effectively interference with very low interference power.When electric-power wire communication signal determination and analysis device does not find known electric-power wire communication signal, single-frequency, random burst, frequency sweep, arrowband or the active interference such as broadband white noise, random waveform frequency modulation can be sent to power line.
In order to the reception input preventing the interference signal disturbing transmitter to send to be input to countermeasure set by power line couples filter feedback causes self-excitation, transmission interference signal and Received signal strength can carry out in timesharing.
When need for electric-power wire communication signal frequency spectrum detecting result to the passband of the communication equipment on power line send targetedly multiband interference signal time, adopt the multi-band interference unit based on electric-power wire communication signal band spectrum testing result shown in Fig. 9.Electric-power wire communication signal band spectrum detector receives the signal in electric-power wire communication signal frequency band, and adopt the method such as Fourier analysis, periodogram to carry out power spectrum detection to received signal, according to this testing result, control jamming pattern, jamming bandwidth and interference band quantity that interference signal produces.Such as, electric-power wire communication signal band spectrum detector passes through spectra calculation, detect within the scope of the 10MHz ~ 15MHz of power line passband and 25MHz ~ 30MHz that there is obvious signal power, then can produce arrowband interference or Sweeping nonlinearity by multi-band interference unit generator in 10MHz ~ 15MHz and 25MHz ~ 30MHz two frequency band ranges.
Detect when needing the pilot signal for electric-power wire communication signal, and according to this testing result to the passband of the communication equipment on power line send targetedly Pilot Interference signal time, adopt the Pilot Interference device based on power line communication pilot signal detection result shown in Figure 10.Power line communication pilot signal detector receives the Received signal strength (such as B point receives the Received signal strength from power line from Fig. 1) from power line couples filter, with the known communication standard prestored, the pilot signal that product uses carries out relevant matches, when matching result instruction obtains signal of communication pilot tone with high probability, then according to the frame structure of signal, in the pilot frequency locations of signal of communication, check bit position, the material time points such as Coded modulation parameters transmission insert burst interference, destroy the pilot tone of its signal of communication, the transmission of sign check and Coded modulation parameters etc., thus reach interference object.Such as, power line communication pilot signal detector can prestore the pilot signal of IEEEP1901-2010 power line communication standard, the Received signal strength received in power line communication passband carries out being shifted relevant by symbol to the pilot signal of storage, when finding that correlation is higher than (this threshold value detection probability is as required determined) during a predetermined threshold value, thinking and detecting in power line and adopt IEEEP1901-2010 to carry out the equipment communicated.Based on this pilot frequency locations, according to the physical layer frame structure of IEEEP1901-2010, send the stochastic pulse interference of a string burst after pilot frequency locations, the duration covers whole pilot length.
Detect when needing the OFDM Cyclic Prefix for electric-power wire communication signal, and according to this testing result to the passband of the communication equipment on power line send targetedly Cyclic Prefix interference signal time, adopt the Cyclic Prefix interferance generator based on power line OFDM modulation mode shown in Figure 11.Power line communication OFDM cyclic-prefix detector receives the Received signal strength from power line couples filter, the OFDM symbol length used according to the communication standard of the known use OFDM modulation mode prestored, product and circulating prefix-length parameter, OFDM symbol Cyclic Prefix correlation estimation is carried out to the signal received, namely the sampled value of Cyclic Prefix position part is carried out relevant to the sampled value of OFDM quiet lotus symbol relevant position, and these correlations are sued for peace; Itself and multiple OFDM symbol is averaged.When result of calculation instruction detects OFDM symbol with high probability, then according to OFDM symbol structure, bursty interference pulse can be inserted in follow-up OFDM symbol Cyclic Prefix position, destroys its Cyclic Prefix characteristic.The Cyclic Prefix of OFDM is damaged, and receiver cannot realize synchronous based on Cyclic Prefix; Meanwhile, Cyclic Prefix is the prerequisite ensureing OFDM sub-carrier orthogonality; The destruction of orthogonality makes to interfere with each other between subcarrier.Like this, the power line communication receiver based on OFDM cannot normally receive and detect its signal of communication.
A kind of processing forward type interference unit, as shown in figure 13, comprising: power line interface, DC power supply, power line couples filter, Received signal strength forwarding processor and power amplifier.Its Received signal strength forwarding processor receives the electric-power wire communication signal through the input of power line couples filter, through certain linear processes process, keep the power spectrum of power spectrum signal after treatment and input to have same structure, but the electric-power wire communication signal of input is uncorrelated or independent with interference signal again; Signal is after treatment sent into power amplifier and is forwarded to power line.The countermeasure set of this processing forward formula is suitable for utilizing the communication band of electric line communication system self to build interference signal, without the need to detecting electric-power wire communication signal frequency spectrum, does not also need to analyze signal of communication.Such as, the power line communications apparatus that passband bandwidth is 70MHz is disturbed, be the cycle carry out segmentation by the signal of communication of power line according to 1ms, then every section of 1ms signal halves become 10 parts, then these 10 parts of signals are carried out random interleaving by part; Then, the signal after intertexture is sent to power line after power amplification.Such as, 10 parts of former sequences of signal are (1,2,3,4,5,6,7,8,9,10), and after interweaving, its order becomes (8,2,10,7,4,3,6,9,5,1).Interleaver also can change at random in time.It is long time that the duration of 0.1ms is about 70MHz bandwidth relative to power line, and the power spectrum signal after intertexture and input signal power spectrum have roughly the same structure.Interference power spectrum is composed close with communication signal power, and random interleaver makes signal of communication and interference independently, and communication control processor cannot carry out Interference Cancellation by Interference Estimation, can resist the anti-jamming of communication control processor.In order to prevent disturb transmitter send interference signal by power line feedback filter feed back input to countermeasure set reception input cause self-excitation, transmission interference signal and Received signal strength can timesharing carry out.This jammer, by receiving the signal of communication on power line, forwards, the interference effect that can realize after the process such as storage, intertexture, every part of signal cycle displacement.
If electric-power wire communication signal is x (t), it is cut with T time length, obtains ..., x 1(t), x 2(t), Its these cut after the Fourier transform of waveform be respectively ..., X 1(ω), X 2(ω) ...Estimate that its power spectrum obtains power spectrum estimation value and is according to the method for periodogram its L is the sample number of fragments that the participation chosen is estimated.Observed by this power spectrum estimation formula, carry out random interleaving to L part signal, its periodogram power spectrum estimation value is identical with original signal.Also find out from this formula, random interleaving is carried out on L part signal, every part of signal+1 ,-1 random weighting all can not affect power spectrum; For I, Q complex signal, random phase twiddle factor can also be adopted to x it () weighting, spectrum results is constant.Wherein for the random phase factor.In addition, to each segment signal x it () carries out cyclic shift, its spectrum results is constant (notices Fourier transform relation wherein represent signal x it () is with T sfor expanding the cycle, the result with time delay τ cyclic shift).
Gather signal of communication in power line, to the interference signal that the process such as its segmentation, intertexture, phase weighting, every part of signal cycle displacement are formed, substantially maintain the power spectrum of original signal.Interference power spectrum has substantially identical structure with power spectrum signal, and in the frequency band that signal is strong, interference power strengthens thereupon, therefore has very strong adaptive disturbance ability; Meanwhile, for the frequency band not having signal of communication, interference power is very weak, improves the service efficiency of interference power.Because signal have passed through random interleaving, phaseweighting method process, the carrier synchronization, frame synchronization, demodulation, channel decoding, CRC check etc. of the receiver of power line communication all cannot normally work, its repeat request signal also cannot receive, and therefore receiver cannot normally receive and demodulate its signal of communication.In addition, signal is carried out to the interference signal of the randomization such as random interleaving, phaseweighting method formation, it blocks original position, interleaving mode, phase weighting value, interleave depth, cyclic shift time delay have randomness, power line communications apparatus cannot be suppressed interference by interference estimation method, has very strong antagonism anti interference ability.
Figure 14 is a kind of annexation using the interferance generator of transformer-coupled power line communication countermeasure set, power line couples filter and DC power supply and power line; Interference signal is sent to power line by countermeasure set, power line communication passband signals is input to countermeasure set by power line.A () figure is that power line couples filter and DC power supply adopt parallel join.Wherein, power line L represents " live wire ", and power line N represents " zero line ".In this connection, its " live wire " and " zero line " is interchangeable.Usually, there is higher power-frequency voltage (such as, the frequency of power frequency electric power is 50Hz or 60Hz, and voltage is 220V or 110V) between " live wire " and " zero line " of power line.Wherein the output of interferance generator is connected with solid line with power line couples filter, represents that the output signal of interferance generator is sent to power line through power line couples filter; One of power line exports to input with one of interferance generator and is connected with dotted line, and expression power line couples filter is coupled alternatively from power line and is input to the receiving element of interferance generator.Such as, in the countermeasure set of the power line communication of Fig. 2 to Fig. 7, interference generator does not need to receive from the input signal in power line communication frequency band, cancels the dotted line connection that power line couples filter is input to interferance generator.In the countermeasure set of the power line communication of Fig. 7, Fig. 8, Fig. 9, Figure 10, Figure 11 and Figure 13, interference generator need receive from the input signal in power line communication frequency band, retains the annexation that power line couples filter is input to interferance generator.
B in () figure, three round rectangles are respectively interferance generator, DC power supply and power line couples filter.In the present embodiment, interferance generator adopts the method for Digital Signal Processing to build, and comprises Digital Signal Processing, transmitting branch and receiving branch.Digital Signal Processing can be a single-chip microcomputer with simple signal process and controlling functions, also can be the stored program processing unit of band digital signal processor, memory, associated peripheral circuits and signal transacting, can also be specialized designs application-specific integrated circuit (ASIC) etc., complete the generation of interference signal, the passband signals treatment and analysis of power line communication and the control work of each correlation module.Transmitting branch comprises digital-to-analogue conversion, bandpass filtering, power amplifier and transmitting line driver.Receiving branch comprises receiver, bandpass filtering and analog-to-digital conversion.When the interference generator of countermeasure set does not need to receive from input signal in power line communication frequency band, cancel receiving branch and the Digital Signal Processing control connection to analog-to-digital conversion and power amplifier.When the interference generator of countermeasure set needs to receive from input signal in power line communication frequency band, retain receiving branch and the Digital Signal Processing control connection to analog-to-digital conversion and power amplifier.
In the present embodiment, if there is transmitting branch and receiving branch simultaneously, adopt the method for time-division to send interference and receive the signal of communication of power line, the interference signal sent to avoid interference generator feeds back to digital signal processing unit by receiving branch.Such as, the time slot that can be divided into duration T by the time be the cycle.In the time T of a time slot, 0 ~ T atime is used for receiving signal of communication possible on power line; T athe time of ~ T is used for sending interference signal, and its signal sent is the interference targetedly that digital signal processing unit generates based on signal analysis result in the power line passband received before this.At 0 ~ T ain time range, the digital signal processing unit of interferance generator controls the analog-to-digital conversion connecting receiving branch, turns off the power amplifier of transmitting branch.Signal in power line communication passband is filter coupled to electric capacity C2 through power line couples, after receiver, bandpass filtering and analog-to-digital conversion, be input to digital signal processing unit, converted by the analysis of digital signal processing unit settling signal, process, linear processes.Such as segmentation in time to received signal, more every segment signal is cut into many parts, to the signal after cutting and by part intertexture and phase weighting etc.; Or analyze the pilot tone of Received signal strength, and produce the burst for pilot tone.At T awithin the scope of ~ T time, the digital signal processing unit of interferance generator controls the power amplifier connecting transmitting branch, turns off the analog-to-digital conversion of receiving branch; The numeric field power line interference signal of generation is sent into digital to analog converter and is converted to analog signal by digital signal processing unit, power amplifier is sent into again after bandpass filtering, be sent to electric capacity C1 via transmitting line driver, be sent to power line through power line couples filter.In the present embodiment, the analog to digital converter of interferance generator receiving branch adopts direct bandpass sampling, so there is no the aobvious down-converter unit contained; The digital signal of transmitting branch converts directly to the signal passband of power line after digital-to-analogue conversion through bandpass filtering, so there is no the aobvious upconverting unit contained.
The power line couples filter of the countermeasure set of Figure 14 (b) adopts transformer coupled, the interference signal of interferance generator is sent and is coupled to power line, and optionally the Signal reception in power line communication passband is coupled to the receiving branch (when interferance generator does not have receiving branch, also not comprising capacitor C2 in power line couples filter) of interferance generator.The interference signal of interferance generator, by transmitting line driver drives, is coupled to power line L and N through transformer T1, capacitor C1, C3 and inductor L1; The signal of power line communication passband is coupled to the receiving branch of interferance generator through transformer T1, capacitor C3, C2 and inductor L1.Suitably choose the value of capacitor C1 and C2, the signal of communication in the interference signal that interference generator is produced and power line communication frequency band by; Namely select the value of C1 and C2, make in the spectral range of these signals, signal presents lower impedance; In the C3 and inductance L 1 of series connection, select the value of capacitor C3 and inductance L 1, make in the spectral range of these signals, signal presents lower impedance.Such as, for the 200KHz place of above-mentioned interference and electric-power wire communication signal, the value of L1 and C3 can be selected, make it, at 200KHz place, series resonance occurs; Now, the signal in 200KHz and a neighbouring frequency range thereof will present lower impedance.
The high voltage of power line and transmitting line driver Tx and receiver Rx are also isolated by transformer T1.In figure, R1 is the first pressure limiting equipment, such as metal oxide varistor or surge suppressor, for limiting the voltage at power line interface L and N two ends.Such as, be in the electric power system of 220V alternating voltage in rated voltage, choose metal oxide varistor, make the voltage clamping at its two ends in 270V.When the voltage on power line is lower than 270V, R1 is high-impedance state, and signal coupling circuit normally works; When appearance high pressure on power line, R1 will become low resistive state from high-impedance state, and by its both end voltage clamper in 270V.The high pressure that the A winding two ends that this metal oxide varistor limits transformer T1 may occur, the high pressure that the X winding two ends that simultaneously also limit the transformer T2 in DC power supply may occur.In figure, D1 is the second pressure limiting equipment, such as, be Zener diode, is used for the voltage of limiting transformer B side.For receiver and the transmitter of routine, the deboost of the second pressure limiting equipment is generally chosen as 5V.
The input of DC power supply is connected across between power line L and N, is parallel to power line with power line couples filter; Wherein, electric capacity C10 is connected across the input power cord two ends of step-down transformer T2, to suppress the electromagnetic interference that may enter power supply.The capacitance of this capacitor is generally greater than 1 nanofarad, such as, is chosen as 100 nanofarads.Alternating voltage is coupled to Y winding two ends and Z winding two ends by step-down transformer T2 respectively, respectively by capacitor C6 and C7, C4 and C5 low-pass filtering after diode bridge rectification, and carries out pressure regulation by linear voltage regulator R3 and R2.Capacitor C9 and C8 is used for ripple and the clutter of filtering DC power supply.
Figure 15 is a kind of annexation of the interferance generator of the countermeasure set using capacity coupled power line communication, power line couples filter and DC power supply and power line; A () figure gives power line couples filter and DC power supply adopts connected in series, the annexation schematic diagram of each module of countermeasure set and power line.In this connection, its " live wire " and " zero line " is interchangeable.Wherein the output of interferance generator is connected with solid line with power line couples filter, represents that the output signal of interferance generator is sent to power line through power line couples filter; One of power line exports to input with one of interferance generator and is connected with dotted line, and expression power line couples filter is coupled alternatively from power line and is input to the receiving element of interferance generator.Such as, in the countermeasure set of the power line communication of Fig. 2 to Fig. 7, interference generator does not need to receive from the input signal in power line communication frequency band, cancels the dotted line connection that power line couples filter is input to interferance generator.In the countermeasure set of the power line communication of Fig. 7, Fig. 8, Fig. 9, Figure 10, Figure 11 and Figure 13, interference generator need receive from the input signal in power line communication frequency band, therefore retains the annexation that power line couples filter is input to interferance generator.
B () figure is the simplified block diagram of the interferance generator of countermeasure set, power line couples filter and DC power supply, simplified electrical circuit diagram and annexation thereof.In the present embodiment, interferance generator adopts the method for Digital Signal Processing to build, and comprises Digital Signal Processing, transmitting branch and receiving branch.Digital Signal Processing can be a single-chip microcomputer with simple signal process and controlling functions, also can be the stored program processing unit of band digital signal processor, memory, associated peripheral circuits and signal transacting, can also be custom-designed application-specific integrated circuit (ASIC) etc., complete the generation of interference signal, the passband signals treatment and analysis of power line communication and the control work of each correlation module.Transmitting branch comprises digital-to-analogue conversion, bandpass filtering, power amplifier and transmitting line driver.Receiving branch comprises receiver, bandpass filtering and analog-to-digital conversion.
In the present embodiment, if there is transmitting branch and receiving branch simultaneously, adopt the method for frequency division to send interference and receive the signal of communication of power line, the interference signal sent to avoid interference generator feeds back to digital signal processing unit by receiving branch.Such as, the time slot that can be divided into duration T by the time be the cycle.The transmitting branch of interferance generator and receiving branch band-pass filter have the adjustable ability of passband.Such as, transmitting branch band pass filter has two passband W1 ~ W2 and W2 ~ W3; Receiving branch band-pass filter also has this two passband W1 ~ W2 and W2 ~ W3.Digital signal processing unit sends control command by the control line be connected with band pass filter, carries out passband conversion.In first time cycle i.e. 0 ~ T, pass through Digital Signal Processing, the interference in W1 ~ W2 frequency range is sent at transmitting branch, now transmitting filter is operated in passband W1 ~ W2 scope, and its signal sent is the interference targetedly that digital signal processing unit generates based on the W1 ~ W2 power line communication inband signal analysis result received before this time slot; Receiving branch filter is operated in passband W2 ~ W3 scope, and the analog to digital converter of receiving branch gathers the signal in W2 ~ W3 frequency range, sends into digital signal processing unit treatment and analysis.In second period of time T ~ 2T, transmitting branch sends the interference in W2 ~ W3 frequency range, now transmitting filter is operated in passband W2 ~ W3 scope, and its signal sent is the interference targetedly that digital signal processing unit generates based on the W2 ~ W3 power line communication inband signal analysis result received before this time slot; Receiving branch filter is operated in passband W1 ~ W2 scope, and the analog to digital converter of receiving branch gathers the signal in W1 ~ W2 frequency range, sends into digital signal processing unit treatment and analysis.The like, tenability time sends the interference signal to power line communication to power line incessantly.
The power line couples filter of the countermeasure set of Figure 15 (b) adopts capacitive coupling, the interference signal of interferance generator is sent and is coupled to power line, and optionally the Signal reception in power line communication passband is coupled to the receiving branch (when interferance generator does not have receiving branch, not comprising capacitor C2 in power line couples filter) of interferance generator.The interference signal mailing to power line of transmitting line driver drives is coupled to power line through electric capacity C1, inductance L 1; Signal of communication possible in the pass band of power line communication is coupled is input to the receiver of interferance generator through inductance L 1, electric capacity C2.Suitably choosing the value of electric capacity C1, electric capacity C2 and inductance L 1, making the L-C series circuit of the L-C series circuit of inductance L 1 and electric capacity C1, inductance L 1 and electric capacity C2 to presenting Low ESR (or presenting Low ESR in the power line pass band of needs interference) in electric-power wire communication signal passband.Choose electric capacity C3, make C3 to high frequency (signal in the passband of power line communication, the interference signal of interferance generator, power line high-frequency noise) short circuit, very high impedance is presented to power frequency, to avoid alternating current to be shorted to ground.Choose inductor L2, on the one hand, the inductance value of L2 should be enough large, make it present larger impedance to the passband of power line communication and the interference signal of interferance generator, to ensure that the interference signal that interference generator is sent to power line can be coupled to power line; And the signal of communication on power line can be coupled to the receiving branch of interference generator.On the other hand, the inductance value of L2 also should be enough little, to ensure to present Low ESR in alternating current power frequency, makes live wire electric power be coupled to the input of the step-down transformer T1 of DC power supply by L2.Like this, the FireWire port port that the interference signal that interference generator is sent to power line is connected from inductance L 1 with inductance L 2 is sent to power line serially; Signal of communication possible in power line communication passband is input to the receiving branch of interferance generator serially from the FireWire port port that L1 is connected with inductance L 2.
In figure, R1 is the first pressure limiting equipment, such as, can be metal oxide varistor, is connected across between power line L and N, carries out overvoltage protection to the power line couples filter of connecting and DC power supply.Such as, be in the electric power system of 220V alternating voltage in rated voltage, choose metal oxide varistor, make the voltage clamping at its two ends in 270V.D1 is the second pressure limiting equipment, such as, be Zener diode, is used for the voltage at limiting transformer inductance L 2 two ends, with the high pressure avoiding the connectivity port of power line couples filter and interferance generator to occur.For receiver and the transmitter of routine, the deboost of the second pressure limiting equipment is generally chosen as 5V.
The input of DC power supply is connected to a power input lines of power line couples filter, and the other end of DC power supply is connected to zero line N, and such power line couples filter and DC power supply form cascaded structure.Equally, electric capacity C10 is connected across the input power cord two ends of step-down transformer T2, to suppress the electromagnetic interference that may enter power supply.The capacitance of this capacitor is generally greater than 1 nanofarad, such as, is chosen as 100 nanofarads.Alternating voltage is coupled to Y winding two ends and Z winding two ends by step-down transformer T2 respectively, respectively by capacitor C6 and C7, C4 and C5 low-pass filtering after diode bridge rectification, and carries out pressure regulation by linear voltage regulator R3 and R2.Capacitor C9 and C8 is used for ripple and the clutter of filtering DC power supply.
Figure 16 is the countermeasure set of electric-power wire communication signal short circuit of the present invention and bypass type and several realization example.Wherein, (a) countermeasure set block diagram that is electric-power wire communication signal short circuit type.Electric-power wire communication signal short circuit/bypass apparatus, by socket, slot and socket type, is connected to power line by the interface of power line.Electric-power wire communication signal short circuit/bypass apparatus comprises the network that to the passband of power line communication is low-resistance, this network is connected in parallel on power line two ends, to the signal of communication bypass that the power line communications apparatus being connected in parallel on same power line local area network (LAN) sends, cause the significantly decay of receiver place signal of communication in pass band, thus make its receiver cannot correctly restituted signal, disturb or suppress it to communicate; This network also shows higher impedance to civil power power frequency, so that ensure can not the electric power of bypass civil power power frequency, makes electric power can normal transmission along power line.Such as, for the power line communication CENELEC frequency range of low transmission rate, the signal passband of its D class home automation application is 3KHz ~ 9KHz.For the power line communication HomePlug1.1 of high-speed transfer, its pass band is 4.49MHz ~ 20.7MHz.For stoping the power line communication in these frequency bands, building short circuit/bypass network, making in these band limits, the input impedance of countermeasure set far below power line load impedance, thus effectively by the signal of communication short circuit on power line or bypass.
As an embodiment, Figure 16 (b) gives a kind of capacitor type short circuit/bypass apparatus countermeasure set.Such as, choose one and have the voltage of resistance to 1000V, capacitance is the electric capacity of 1uF.For the power frequency civil power of 50Hz, this electric capacity presents the impedance of 3183 ohm, therefore can not impact normal electric power transfer (be published in the statistical data analysis in the article " low-voltage network power line carrier communication new technology " of " low-voltage electrical apparatus " periodical, the 2nd phase in 2006,5-7 page according to Liu Xiaosheng etc., the statistics impedance of indoor power line is generally between 5 ~ 15 ohm).Be 1MHz place in frequency, the impedance of this electric capacity is about 0.16 ohm; Be 10MHz place in frequency, the impedance of this electric capacity is about 0.016 ohm.Therefore, this short-circuit bypass device can to 1MHz and above signal of communication effective bypass.Figure 16 (c) is the capacitive bypass network that have employed pressure limiting equipment.Its pressure limiting equipment can be metal oxide varistor or surge suppressor, and for limiting the voltage at power line interface L and N two ends, electric capacity is not breakdown burns in protection.Such as, be in the electric power system of 220V alternating voltage in rated voltage, choose metal oxide varistor, make the voltage clamping at its two ends in 270V.Figure 16 (d) is a kind of short circuit based on L-C resonance/bypass countermeasure set.L1 and C1 can be selected to make series L-C circuit L1-C1 to the short circuit of frequency f 1 resonance, L2 and C2 is selected to make series L-C circuit L2-C2 to the short circuit of frequency f 2 resonance, thus make signal of communication produce deep fade at f1 and f2 place, with stop by power line frequency f 1 and f2 and near transmission signal of communication.Meanwhile, L1, C1 and L2 and choosing of C2 should ensure that its series circuit shows higher resistance to mains frequency, can not cause bypass to civil power.The value of f1 and f2 is greater than civil power power frequency.Short circuit/bypass the jamming equipment of Figure 16 (b), after pulling out from power line socket, socket or slot, its electric capacity may store certain electric charge.For ensureing safety, can by the Machine Design of power line interface, after assurance device is extracted from power line socket, slot or socket, people can not touch the metal of interface end.Also suitable discharge protection circuit can be increased on circuit.This protective circuit ensures that countermeasure set transfers to rear regular picture; Meanwhile, do not affect its bypass to electric-power wire communication signal when the interpolation of protective circuit also should ensure countermeasure set access power line work, do not affect the normal electric power transfer of power line yet.
The countermeasure set of electric-power wire communication signal short circuit type has well interference and inhibition for the communication of the power line communications apparatus be connected in parallel on power line.But this Communication Jamming and disturbance restraining method send and receiver for adopting the power line communication of series connection injection mode, and its Communication Jamming is not obvious with the inhibition that communicates.In this case, other active signal of the present invention is adopted to disturb more effective.
Power line communication countermeasure set of the present invention, the power line communication countermeasure set with determination and analysis function, processing forward type countermeasure set, by sending interference to power line, reducing the signal interference ratio of power line communication receiver, thus suppressing it to communicate.Short circuit of the present invention, bypass type countermeasure set, by electric-power wire communication signal short circuit and bypass, reduce the effective received signal power of receiver, thus reduce the signal interference ratio of power line communication receiver, blocks its communication.The various alternatives of these interference and these interference also may be combined with into composite interference device, reach better interference effect.
The above is preferred embodiment of the present invention, and the present invention should not be confined to the content disclosed in this embodiment and accompanying drawing.Every do not depart from spirit disclosed in this invention under the equivalence that completes or amendment, all fall into the scope of protection of the invention.

Claims (3)

1. a power line communication countermeasure set, is characterized in that: comprise power line interface, DC power supply, power line couples filter, power amplifier and interference signal generator, also comprises electric-power wire communication signal determination and analysis device;
Wherein, interference signal generator exports and is connected to power amplifier; Power amplifier exports and is connected to power line couples filter; Power line couples filter, DC power supply are connected with power line interface respectively; DC power supply is connected with interference signal generator, power amplifier;
Power frequency civil power is converted to low-voltage DC by described DC power supply, for power amplifier and interference signal generator are powered;
Described power line interface adopts socket, slot and socket type, provides the interface of countermeasure set and power line;
Described power line couples filter complete forceful electric power and light current isolation, overvoltage and overcurrent protection, interference export passband high pass or bandpass filtering, output signal is coupled to power line, realize the impedance matching of power line transmission channel and interference output;
Interference signal needed for described interference signal generator produces;
Described power amplifier completes the power amplification of interference signal;
Described electric-power wire communication signal determination and analysis device is connected between interference signal generator and power line couples filter; Receive the signal in electric-power wire communication signal frequency band, and carry out to received signal detecting, analyzing; DC power supply is its power supply;
Described electric-power wire communication signal determination and analysis device and the interference signal generator be attached thereto adopt power line communication OFDM Cyclic Prefix correlation detector and Cyclic Prefix interferance generator respectively, power line communication OFDM Cyclic Prefix correlation detector extracts and analyzes OFDM symbol original position, the circulating prefix-length information of Received signal strength, and controlled circulation prefix interferance generator produces the interference signal destroying OFDM Cyclic Prefix;
Or adopt electric-power wire communication signal band spectrum detector and multi-band interferance generator, electric-power wire communication signal band spectrum detector receives electric-power wire communication signal inband signal, and carry out power spectrum detection, control the jamming pattern of interference signal, jamming bandwidth and interference band quantity, multi-band interferance generator produces multi-band interference signal;
Or adopt power line communication pilot signal detector and Pilot Interference generator, power line communication pilot signal detector extracts and analyzes the pilot frequency information of Received signal strength, according to pilot frequency mode, pilot frequency locations, pilot length information, control Pilot Interference generator and produce specific aim Pilot Interference signal.
2. a kind of power line communication countermeasure set according to claim 1, is characterized in that:
Described interference signal generator also can adopt single-frequency signal generator, or bandpass-type white Gaussian noise interference unit, or arrowband type white Gaussian noise interference unit, or white Gaussian noise frequency-modulated jammer, or Sweeping nonlinearity device, or random waveform frequency-modulated jammer;
Described bandpass-type white Gaussian noise interference unit comprises Gaussian white noise generator and band pass filter; Arrowband type white Gaussian noise interference unit comprises Gaussian white noise generator and narrow band filter; White Gaussian noise frequency-modulated jammer comprises voltage controlled oscillator, narrow band filter and Gaussian white noise generator; Sweeping nonlinearity device comprises voltage controlled oscillator and Saw-tooth Signal Waveform Generator; Random waveform frequency-modulated jammer comprises voltage controlled oscillator and AWG (Arbitrary Waveform Generator);
Described single-frequency signal generator is connected to power amplifier; After power amplification, be input to power line by power line couples filter, mono-tone interference is carried out to the power line communication receiver on power line;
The band pass filter of described bandpass-type white Gaussian noise interference unit covers more than 10% bandwidth of electric-power wire communication signal passband; Described arrowband type white Gaussian noise interference unit accounts for power line passband 10% and following bandwidth;
The output of described Gaussian white noise generator is connected to band pass filter or narrow band filter; For white Gaussian noise frequency-modulated jammer, its narrow band filter exports voltage controlled oscillator to and carries out frequency modulation; The output of band pass filter or narrow band filter or voltage controlled oscillator is connected to power amplifier; Be input to power line by power line couples filter, broadband or arrowband interference are carried out to the power line communication receiver be connected on power line;
The output of described Saw-tooth Signal Waveform Generator is connected to voltage controlled oscillator and carries out frequency modulation and obtain swept-frequency signal; Voltage controlled oscillator exports and is connected to power amplifier;
Described AWG (Arbitrary Waveform Generator) connects voltage controlled oscillator and carries out frequency modulation, and its output is connected to power amplifier.
3. a kind of power line communication countermeasure set according to claim 1, it is characterized in that: adopt Received signal strength forwarding processor to replace described interference signal generator, time slice is carried out, by section random interleaving, by section phase weighting, linear processes process by section cyclic shift to electric-power wire communication signal inband signal, obtain processing forward type interference signal, formation processing forward type power line communication countermeasure set.
CN201210500190.4A 2012-11-30 2012-11-30 Power line communication countermeasure set Expired - Fee Related CN103856242B (en)

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