Method for increasing concealment of transmission of group of binary useful signals, manipulated by amplitude, phase or frequency
 Method for protection of speech data signal, transferred along communication lines / 2249307Transferred signal is concealed via adding noises to communication line in speech frequency range with linear addition of speech data signal with noise signal of higher level. Concealment is removed via adaptive filtration of received signal with compensation of noise component and separation of data component. Addition of noises to communication line is performed from the side of sensor. Noise signal during addition of noises and adaptive filtration is formed of a sum of counts of several noise series with nonevent sizes via their random querying. At the beginning of each communication session a signal is sent to side of receiver, characterizing order of querying of series, and starting signal, providing for synchronism of noises addition and filtering processes. All operations are performed by means of microprocessors, mounted on both sides of communication line, dependently of loaded software providing for change of direction of transmission and protection of speech data signal. Invention allows to simplify protection while providing for absolute confidentiality of transmitted data. |
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Method for protection of speech data signal, transferred along communication lines / 2249307 Transferred signal is concealed via adding noises to communication line in speech frequency range with linear addition of speech data signal with noise signal of higher level. Concealment is removed via adaptive filtration of received signal with compensation of noise component and separation of data component. Addition of noises to communication line is performed from the side of sensor. Noise signal during addition of noises and adaptive filtration is formed of a sum of counts of several noise series with nonevent sizes via their random querying. At the beginning of each communication session a signal is sent to side of receiver, characterizing order of querying of series, and starting signal, providing for synchronism of noises addition and filtering processes. All operations are performed by means of microprocessors, mounted on both sides of communication line, dependently of loaded software providing for change of direction of transmission and protection of speech data signal. Invention allows to simplify protection while providing for absolute confidentiality of transmitted data. |
 Method for increasing concealment of transmission of group of binary useful signals, manipulated by amplitude, phase or frequency / 2282941Method includes independent emission of each useful signal and broadband masking signal in range of frequencies of whole group of useful signals, their adding and following suppression of masking signal during receipt, while broadband masking signal has value of bearing frequency, divisible by value, reverse relatively to duration of one element of useful digital information and structure, periodical in time, while suppression of masking signal during receipt is performed in accordance to compensation method with delay. |
 Method for secret transfer of information / 2295835In accordance to method, original chaotic determined signal is generated by first chaos generator, transferred via communication channels, received and divided onto two identical signals, while first signal affects second generator with possible production of signal, synchronized to original signal, subtracted from which is second signal, producing useful digital signal, and generation of signal is realized by modulating parameters of chaotic signal by useful one, and second identical signal affects third generator, identical to second one in terms of control parameters, while first and second generators are picked with possible setup of generalized chaotic synchronization mode. |
 Method and device for pulse overlap compensation in digital-modulation signals / 2298877Proposed method for pulse overlap compensation in digital modulation signal includes reception of first pulse train for producing first train of modulated pulses, demodulation of first modulated pulse train to produce first demodulated pulse train, addition of first demodulated pulse train to first pulse train to produce first error pulse train, modulation of first error pulse train to produce first modulated error pulse train, and addition of first modulated error pulse train to first modulated pulse train to produce compensated pulse train. |
 Method for creating a speech-like masking signal / 2308159Speech-like signal is composed of original signal being masked by modulation with noise signal of moments when signal being masked crosses zero. Modulation of zero crossing moments of speech signal may be performed by phase modulation of speech signal by noise signal. Modulation of zero crossing moments of speech signal may also be performed in accordance to a different algorithm - speech signal is clipped, resulting clipped signal is integrated, resulting saw-shaped signal is added to noise signal, after that resulting digital signal is clipped. For masking speech signal in digital form, resulting masking signal is added to the same signal converted to digital form. Modulating signal is a noise signal. Control listening indicates that resulting signal is unintelligible, although it preserves the speech-like form. |
 Generator of speech-like noise signal / 2310282In accordance to the invention, a masking signal should be generated, which simultaneously masks analog signal and speech signal in digital form. Speech-like signal is created on basis of original signal being masked by means of modulation of zero intersection moments of masked signal by a noise signal. To modulate zero intersection moments of speech signal, the speech signal is clipped, and then resulting clipped signal is integrated, transforming it to saw-tooth signal, resulting saw-tooth signal is summed with noise signal, and after that resulting total signal is clipped. To increase masking effect (to exclude pauses, connected to pauses in speech being masked) resulting noise-like signal is summed with second speech-like signal, to generate which noise signal is clipped (which does not have pauses), and then zero intersection points of clipped noise signal are modulated with speech signal. To mask speech signal in digital form, resulting speech masking signal is added to an identical signal converted to digital form. |
 Device for protection of user's telephone set against non-authorised acoustic control / 2350032In device for protection of a user's telephone set against not authorised acoustic control the block (1) connected to a user's telephone line controlling the state of a telephone set with two outputs "handset is free" and "handset is busy", the noise generator, the block of light indication, the block (2) of detection in a telephone line of special signals of guidance, the block (3) of detection of galvanic connection of devices of non-authorised acoustic control, mounted on a telephone line in front of the block (1) controls of a state of a telephone set, and filters (4) system of the inferior frequencies and filters-terminators of the small amplitudes, disposed before a protected telephone set, and also the signals (8) adder, the block (7) of correction of voltage level in a telephone line, the noise generator consists of the block (5) generating "white noise" and the block (6) generating high-frequency noise-like signal, and the indication block (9) in addition contains the block of sound indication. |
 System for transmitting information using random signals / 2369018Invention relates to information transmission with spectrum broadening and can be used in communication systems. The proposed information transmission system using random signals has an information source, multiplexer, delay line, random signal generator, broadband amplifier, communication channel, high-frequency amplifier, first multiplier, tapped delay line, first integrator, second and third multipliers, first generator of a copy of autocorrelation function of random signal, corresponding to information character "1", second generator of a copy of autocorrelation function of random signal, corresponding to information character "0", second integrator, third integrator, subtractor, decision device and information recipient. |
 Method to protect information in communication line against leakage due to external electromagnetic radiation and noise (eemrn) / 2427903Method is carried out by reduction of probability of recognising transmitted data in a communication line. The method to protect information in a communication line against leakage due to external electromagnetic radiation and noise consists in the fact that digital signals transfer along a communication line is terminated. Then this line is complemented with an additional line, and masking signals are sent synchronously together with the transfer along the secured line along this additional line. Besides, amplitude and frequency-time parameters of masking signals are selected so that the picture of external electromagnetic radiations and noise from both lines as a whole that occurs in environment in process of data transfer, is identical for each pulse of transmission. |
 Method for information protection of random antenna / 2474966Method for information protection of a random antenna using a system of jamming emitters involves placing M transponders of the information signal emitted by the random antenna between the random antenna and fixed intercepting equipment. The transponders are connected to amplitude and angular modulators which are connected to M jamming generators which perform stochastic amplitude and angular modulation of the information signals emitted by the random antenna. The fixed intercepting equipment includes N information signal receivers and a computer circuit for processing received signals. |
FIELD: radio engineering, possible use in radio communication systems, meant for functioning under conditions of radio-electronic combat.
SUBSTANCE: method includes independent emission of each useful signal and broadband masking signal in range of frequencies of whole group of useful signals, their adding and following suppression of masking signal during receipt, while broadband masking signal has value of bearing frequency, divisible by value, reverse relatively to duration of one element of useful digital information and structure, periodical in time, while suppression of masking signal during receipt is performed in accordance to compensation method with delay.
EFFECT: increased concealment of transfer of a group of binary useful signals.
19 dwg
The present invention relates to the field of radio and can be used in radio systems designed for operation in conditions of electronic warfare (EW), when the signal transmission is accompanied their exploration and suppression of the enemy.
The reliability of information transmission under conditions of ECM depends essentially on the energy and structural secrecy of the applied signals. It is now widely known methods of transmitting digital information by means of binary signals manipulated by amplitude, phase or frequency, which are not high enough stealth, especially at a slight distance from the transmitter.
Stealth transmission of binary shift keyed signals can be enhanced by additionally emitted masking signals.
Known "way to mask the transmitted messages (Application Germany no OS 3605350, N 04 To 1/02, 1987), according to which on the transmission side of the signal synchronously superimposed masking signal conveys no information, the law of formation is known, therefore, at the receiving side, it can be separated from the useful signal. But it is masked only one useful signal, which is a disadvantage of this method.
Also known transmission method of a masked signal (Avellano Transmission of information using coding masking chaotic oscillations. - Technology and electronics, 2002, t, No. 4, Fig.1, str), which is as follows.
The transmitter combines the formation of a useful and masking signals, using dual transmission: on the second channel transmit only masking the signal, but the first - the same signal into amplitude and phase, summed with the useful signal. At the entrance with its receiver enabled suppressing unit, in which the masking signal transmitted on the second channel, is subjected to a transformation similar to the transformation in the transmitter, and subtract it from the total signal received on the first channel. By removing the masking signal remains only the useful signal. At the entrance of the "other" receiver will operate the amount of useful and masking signals, i.e. the structure of the useful signal will be hidden.
The disadvantage of this method is that it allows you to mask the signal from only one transmitter, although often require masking group "their" transmitters.
Closest to the proposed method is "a Method of increasing secrecy transmission group narrowband signals (RF Patent No. 2232475, priority 10.04.2003,, publ. 10.07.2004, Bulletin No. 19), adopted for the prototype.
Prototype method is as follows.
Emit a collection of useful signals are not avisio from the mask, and radiation masking signal is carried out in the frequency range of the entire group of useful signals. The masking signal is formed from a narrowband signal by extending the spectrum due to frequency or phase modulation, the law which is known for its receivers. In "their" receivers convert all input, including masking, the signal so that the spectrum of the masking signal is narrow, and the spectra of the remaining input signals are expanding, then the masking signal rejection, and then restore the remaining input signals.
However, the prototype method is based on the suppression of the mask signal in the noise suppressing unit method rejectee, has the following disadvantages:
- first, to reduce distortion of the useful signal due to rejectee strip of rejectio must be cut and folded spectrum of the masking signal must be closer to δfunction. It is known that this spectrum has unmodulated sine wave. However, passing through the bandpass filters, the mask signal becomes parasitic modulation, which persists in the block convolution of the spectrum, resulting in a spectrum masking signal at the output of this block has a lateral components, which are not rejections, forming the output of the secondary (residual) masking interference;
the second is, in General difficult to restore the original form of the masked useful signal, i.e. equality
F{F[S(t)]}≡S(t)
where F(...) statement modulation (spread spectrum).
To correct noted deficiencies in the method lies in the independent radiation of each of the useful signal and the broadband masking signal, the summation and subsequent suppression of the masking signal, and the radiation masking signal is carried out in the frequency range of the entire group of useful signals, according to the invention broadband masking signal has the carrier frequency that is a multiple of the reciprocal of the duration of one element of the useful digital information, and a periodic structure in time with a period that is a multiple of the duration of one element of the useful digital information transmitted by means of binary signals, manipulated amplitude (OMA), frequency (FMN) or phase (FMN) and have values of the carrier frequencies (for the case of FMN - manipulated frequencies), multiples of the reciprocal of the duration of one element of the useful digital information, the suppression of the masking signal in "their" receivers carry out the method of compensation with delay, which delay the input mixture signals for a time equal to the period of the broadband masking signal, and ZAT is m subtract it from nezadelannyh mixture signals, and resulting from the compensation of the distortion of the useful signal resolve in blocks recovery of signals presented at the outputs of "their" receivers.
The drawings submitted in the application:
Figure 1 - Functional diagram of a communication system that implements the proposed method.
Figure 2 - Functional block circuit suppression masking signal (BPMS) I.
Figure 3 - Functional diagram of the recovery block signal (BVS) II.
Figure 4 - Number of spectral components of the mask signal in the bandwidth of the useful signal receivers.
Figure 5 - Form periodic broadband masking signal at the receiver input at different scan intervals (a, b).
6 - Form masking signal at the output of the noise suppressing unit after rejectee (prototype) at different scan intervals (a, b).
Fig.7 - Form masking signal at the output BPMS I (the proposed method) at various intervals of the sweep (a, b).
Fig - Form source of useful information signal transmitted in the communication channel.
Fig.9 - Form FMN signal at the receiver input 41(a), the output BPMS I (b) and at the output of receiver 41(b).
Figure 10 - the Shape of the AMS signal at the receiver input 41(a), the output BPMS I (b) and at the output of receiver 41(b).
11 - Form FMN signal at the receiver input 4 (a), the output BPMS I (b) and at the output of receiver 41(b).
Fig - Form input BVS II.
Fig - waveform at the output of the diode bridge BVS II.
Fig - waveform at the output of inverting amplifier DC BVS II.
Fig - Form of the signal at the output of the adder BVS II.
Fig - waveform at the output of the time delay BVS II.
Fig - waveform at the output of the multiplier BVS II.
Fig - waveform at the output of the low pass filter BVS II.
Fig - Form of the output signal of a casting device BVS II.
A functional diagram of a communication system that implements the proposed method, shown in figure 1, where indicated:
I - block suppression masking signal (BPMS);
II - the recovery block signal (BVS);
11one of the group of transmitters useful signals;
12transmitter periodic broadband masking signal;
21, 22lines (channels) of communication;
31, 32- receiving antenna, a summation of incoming signals;
41one of the receivers "their" radio link;
42receiver "foreign" radio.
In this system, as an example, presents one "own" the wireless link, which may be multiple, consisting of a transmitter signal 11lines of communication (radio) 21, receiving the antenna 3 1block suppression masking signal (BPMS) I, "his" receiver 41and recovery block signal (BVS) II.
"Alien" receiver 42playing the role of razvetvlennykh receives the mixture of the output signal of the receiving antenna 32.
The transmitter periodically broadband masking signal of the I2in fact, is the transmitter barrage interference, which in addition to masking signal in its frequency band can suppress the "other" receivers.
The power amplifier and transmitting antenna are not of fundamental importance, therefore, not shown in figure 1.
This radio system is as follows.
The duration of one element of the useful digital information transmitted by means of binary signals manipulated by amplitude, frequency or phase, is equal to the So-Periodic broadband masking signal representing a sequence of repetitive time-segment broadband pulses with duration n·T (where n is the value multiplicity)with the carrier frequency N/T (where N - value ratio), the output of the transmitter 1 is adjudged to be at the receiving antenna 31, 32"his" 21and "alien" 22wireless links. Receiving antenna 32connected to the input of another receiver 42. Antenna 31and 32wt is yuushi signal is summed with other signals, including a useful signal emitted by the transmitter 11.
The values of the carrier frequencies of the useful signals (for the case of FMN - manipulated frequencies) must be equal to the value of M/T (where M=(N±m) - value ratio, m=0, 1, 2... is a positive integer, m<N). In this case, all useful signals located in the frequency band masking signal are disguised spectral components of the latter, the number of which in the bandwidths of the receivers of useful signals is equal to n when n is odd and equal to (n-1) when n is even. Figure 4 shows examples for n=2, 3, 4, 5.
Suppression masking signal in "his" receiver 41by compensation with delay in BPMS I included at the input of receiver 41why delay the input mixture signals for a time equal to the period of the broadband noise, and then subtract it from nezadelannyh mixture of signals.
Elimination of the resulting compensation with delay distortion of the useful signal is in the recovery block signal (BVS) II included at the output of its receiver 41.
At the entrance of the "other" receiver 42all masked useful signals are suppressed powerful spectral components of the masking signal, resulting in their receiving and processing becomes impossible.
Fu is clonally block circuit suppression masking signal (BPMS) I is shown in figure 2, where indicated:
11 - input wideband filter;
12 - device delays the signal by an amount n·T;
13 - device subtraction.
BPMS I provides broadband input filter 11, the inlet of which is the entrance BPM I, and the output is connected to the second input of the subtraction 13 and through the unit delays the signal by an amount n·T 12 with its first input, and the output of the subtractor 13 is output BPMS I.
Band of the input wide-band filter 11 BPMS I agreed with the bandwidth of the masking signal.
The objective of unit I, is the suppression of periodic broadband masking signal by delaying the received mixture signal for a time equal to the period of the n·T repeat segment of the masking signal and the subsequent subtraction of the delayed signal from nezadelannyh mixture. Latency is the delay device 12.
At the output of the subtractor 13, and therefore, the output BPMS I happen compensation (eliminating) the masking signal from the input mixture signals.
Replacement rejectee masking signal compensation delay can increase its suppression, which is conrmed by computer simulation, whose results are presented in figure 5-7.
On figa and 5B shows the waveform of the mask signal is and the input noise suppressing unit with rejection (prototype) and BPMS compensated with a delay (the proposed method) at various intervals of the sweep (figa - 1000 μs, PIGB - 7 ISS), and figa, 6b and 7a, 7b is similar waveforms at the outputs of the noise suppressing unit with rejection and BPMS compensated with a delay, respectively.
The results show that the suppression of the masking signal in BPMS I compensated with a delay significantly (by 30 dB or more) higher than in the noise suppressing unit with rejection.
However, the replacement of rejectio masking signal compensation with delay leads to a distortion of the useful signal in the block suppression masking signal I, which is conrmed by computer simulation, the results for the case n=1, T=0,00004 with N=400, M=396 (m=4) is shown in Fig-11.
On Fig shows an example of waveforms useful source of information of the video signal received in the communication channel.
Figure 9 (a, b, C), 10 (a, b, C), 11 (a, b, C) shows waveforms of the signals (a - inputs "their" receivers 41b - outputs BPM I, on the outputs of their receivers 41for FMN, AMS and FMN signals, respectively.
From FIGU, 10B, 11b, it is seen that the distortion of the signals at the outputs of the receivers 41FMN, AMS and FMN signals are identical, therefore, to restore a useful source of information video (Fig) requires the same device.
The recovery block signal (BVS) II can be performed, for example, in the form of CX is we, shown in figure 3, where indicated:
21 - adder;
22 is a diode bridge;
23 - low pass filter;
24 - unit time delay at time n·T;
25 - inverting DC amplifier with gain equal to 1;
26 - solver;
27 - multiplier.
BVS II contains the adder 21, the first input is combined with the input of the diode bridge 22, and is input BVS II. The output of the adder 21 is connected to the input devices of the time delay at time n·T 24 and low pass filter 23, the output of which through critical device 26 is connected to the output BVS II. The output of the time delay at time n·T 24 connected to the first input of the multiplier 27, the output of which is connected with the second input of the adder 21. The output of the diode bridge 22 through inverting DC amplifier 25 with a gear ratio equal to 1, is connected with the second input of the multiplier 27.
The objective of the unit BVS II, is the elimination of the resulting compensation with delay distortion of the useful signal, i.e. the recovery of the useful signal to the image corresponding to the original information signal (Fig).
The solution to this problem in BVS II is due to the selection of "lost" in the block suppression masking signal I part of the useful signal, which when added with distorted the output useful signal restores its shape.
With this purpose, the input signal BVS II is subjected to a calculation modules with subsequent inversion. The received signal being multiplied with the delayed while n·T recovered signal is not that other, as "lost" in BPMS part I of the useful signal, which is in the feedback circuit is supplied to the adder 21, which is formed with an input signal BVS II.
Thus, the distorted input signal is supplied simultaneously to the first input of the adder 21 and the input of the diode bridge 22, which performs the function of the modulus of the signal. From the output of the diode bridge 22, the signal at the inverting input of the DC amplifier 25 with a gear ratio equal to 1, carrying out the inversion module signal without changing its maximum value. From the output of the adder 21, the restored signal is supplied simultaneously to the device time delay at time n·T 24 and low pass filter 23. The delayed signal is multiplied by the signal from the inverting output of the DC amplifier in block 27. The output of multiplier 27 is formed in the adder 21 with the input distorted desired signal BVS, forming the output of block 21 of the restored signal, high frequency components are suppressed in the low pass filter 23, which increases the reliability of becauseguerrilla 26, performing a logical function: if the input signal is >0, then transferred to "unit", if the input signal <0, then transferred to the "minus one".
The signal at the output of a casting device 26 is an output signal BVS II and corresponds to source useful information signal shown in Fig.
The functioning of the BVS II is illustrated by the waveforms of signals at various points on the structure obtained as a result of computer simulation for the case T=0,00004 (Fig-19).
The way to increase the stealth transmission group useful binary signals manipulated by amplitude, phase or frequency, which consists in an independent radiation of each of the useful signal and the broadband masking signal, the summation and subsequent suppression of the masking signal, and the radiation masking signal is carried out in the frequency range of the entire group of useful signals, wherein the broadband masking signal has the carrier frequency that is a multiple of the reciprocal of the duration of one element of the useful digital information and periodic time structure with a period that is a multiple of the duration of one element of the useful digital information transmitted by means of binary signals manipulated by amplitude, the frequency or phase and having values which ECUSA frequencies (for the case of frequency-shift keying - the manipulated frequencies that are multiples of the reciprocal of the duration of one element of the useful digital information, the suppression of the masking signal in "their" receivers carry out the method of compensation with delay, which delay the input mixture signals for a time equal to the period of the broadband masking signal, and then subtract it from not detained mixture signals, and the resulting compensation of the distortion of the useful signal resolve in blocks recovery of signals presented at the outputs of "their" receivers.