RU2360365C1 - Radio camouflage device - Google Patents

Abstract

FIELD: computer engineering; control systems.

SUBSTANCE: present invention relates to radio camouflaging stray electromagnetic radiation and picking up noise of computer equipment and control systems. The device contains a low-frequency noise source, an active antenna circuit and a noise source, which is made in form of a system of two connected generators, the first of which is a generator with delayed feedback and inertial auto-displacement, and the second - with regulated delayed feedback. The output of the first generator is connected to the input of the second generator using a coupling element, which is a non-directional T junction with step impedance-matching transformers. One arm of the coupling element is connected to a flat spiral antenna.

EFFECT: widening of the operating range in the high frequency band and reduced non-uniformity of spectral density of the camouflage noise signal.

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Description

The present invention relates to radio engineering and can be used to create radio interference transmitters in systems of radio technical masking and protection of information processed by computer technology from leakage through the channels of side electromagnetic radiation and interference (PEMIN). Spurious electromagnetic radiation and interference from computer technology occupy a frequency range from units of kilohertz to 1800 MHz, in the same range it is possible to receive these emissions and restore information processed by a computer using special receivers. In this regard, to protect information from unauthorized use, it is necessary to use special means that prevent the interception of PEMIN. One of these tools is the masking of radiation using noise electromagnetic interference [1].

Known noise generator for interference transmitters in information protection systems and blocking mobile telephone communications, creating a masking interference [2]. The noise generator contains n amplifying elements, two combined multi-resonance oscillatory systems, which are interconnected by a feedback circuit. The disadvantage of this device is the instability of the generator and the dependence of the characteristics of the noise signal on external and internal destabilizing factors (changes in load, temperature, variation in the parameters of active elements).

The Oktava-PC spatial noise system is also known, designed to prevent information leakage through spurious electromagnetic channels and interference, and containing two identical antenna modules that are placed in orthogonal planes connected to the noise generator through a matching device, and there is the possibility of electrical matching of impedances antenna modules with the output resistance of a noise generator for the electric and magnetic components of the electromagnetic field [3]. The disadvantage of this system is that two identical antenna modules are used, which form identical noise fields in space, the superposition of which does not allow to eliminate the spatial unevenness of the amplitude-frequency characteristics of the system.

A device for protecting computer equipment from information leakage through the channels of spurious electromagnetic radiation [4], comprising a noise generator and a loop antenna, in which by changing the configuration of the loop antenna is achieved the creation of a uniform intensity of the electromagnetic masking field in three orthogonal planes. The disadvantage of this device is that the energy spectrum of the masking signal is shifted to the low frequency region.

In [5], a radio masking device is presented, which contains a noise generator in the form of a system of two coupled generators and an emitter, in which, in order to create a masking electromagnetic field in space and increase the level of induced masking interference in electrical networks and utilities with the necessary informative signal / noise ratio in in the range of possible interception, a splitter with one input and N outputs, N buffer stages, made in the form of amplifiers with inertial autosetting, and (N-1) additional emitters, while the output of the noise generator is connected to the input of the splitter, each output of the latter is connected to the input of the corresponding buffer stage, and the input of each radiator is connected to the output of the corresponding buffer stage. The disadvantage of this device is that this complex and expensive product is used only at critical facilities and for economic reasons is not widely used.

A radio masking device [6] is known, comprising a noise generator made in the form of a system of two coupled generators, the first of which is a generator with delayed feedback and inertial autosetting, and the second is made with adjustable feedback, the output of the first generator is connected to the input of the second by an element communications, an active antenna circuit in the form of a magnetic dipole type radiating antenna, one end of which is connected to the output of the second generator, and the other to a common bus, and a low-frequency noise source, additional a splitter has been introduced, the input of which is connected to the output of the low-frequency noise source, and the outputs are connected to the inputs of the first and second generators, respectively. The disadvantage of this device is the low intensity of the masking electromagnetic field and the large unevenness of the spectral density of the noise power in the high-frequency part of the working frequency range.

Of the known radio masking devices, the closest to the proposed technical essence are radio masking devices [7-8], containing a noise generator and an active antenna circuit. The noise generator is made in the form of a system of two generators interconnected by a communication element, the first generator containing a nonlinear amplifier with inertial bias and a delayed feedback circuit, the second generator containing a nonlinear amplifier and an adjustable delayed feedback circuit, the output of the first generator is connected to the input of the second generator using a capacitive coupling element, and the active antenna circuit is made in the form of a radiating antenna, one end of which is connected to the output of the second generator, etc. ugo - with a common bus. To increase the stability of the radio masking device, a low-frequency noise source is introduced into the circuit, the output of which is connected to the input of the first generator. The disadvantage of this device is the low level of spectral density of noise power in the high-frequency region of the operating range, which is due to the limited capabilities of a single antenna when operating in the frequency band from 0.01 to 1800 MHz.

The technical problem to which the invention is directed is to expand the operating range to the high frequency region and reduce the unevenness of the spectral density of the noise signal. According to [9, 10], the frequency band of masking vibrations of radio masking devices should exceed the frequency range of PEMIN of computer equipment, and the ratio of the levels of masking vibrations should be 10 ÷ 15 dB higher than the level of informative radiation in the entire frequency range of PEMIN.

To do this, in a radio masking device containing a noise generator, an active antenna circuit and a low-frequency noise source, in which the noise generator is made in the form of a system of two coupled generators, the first of them is a generator with delayed feedback and inertial auto-bias, the second generator with adjustable feedback, the output of the first generator is connected to the input of the second generator using a communication element, the active antenna circuit is made in the form of a magnetic dipole type radiating loop antenna, one end which is connected to the output of the second generator, and the other to the common bus, the output of the low-frequency noise source is connected to the input of the first generator, a flat spiral antenna is introduced, and the communication between the generators is carried out using the said communication element, which is an unidirectional tee with step matching transformers , the shoulder (a) of the communication element is connected to the output of the generator 1, the shoulder (c) of the communication element is connected to the input of the second generator, the shoulder (c) of the communication element is connected to a flat spir Al antenna.

The list of drawings:

Figure 1 - Structural diagram of the inventive device radio masking.

Figure 2 - Spectrograms of oscillations:

a) generator 1, b) generator 2, c) noise generator.

Figure 3 - Diagrams of antennas of the radio masking device and their radiation patterns:

a) Archimedean spiral, b) logarithmic spiral, c) radiation pattern of the spiral antenna, d) loop antenna, e) radiation pattern of the loop antenna.

Figure 4 - Electrical diagram of a device specific implementation.

Figure 5 - Distribution in space of the electromagnetic field generated by the antennas at the frequencies of the working range: a - 50 MHz, 6 - 500 MHz, in - 1800 MHz.

• - loop antenna;

◇ - spiral antenna;

▬ - frame and spiral antenna.

6 - Levels of spectral density of informative and masking signals:

1 - PEMIN, 2 - radio masking device with a frame antenna, 3 - radio masking device with a frame and spiral antennas.

The inventive radio masking device, the structural diagram of which is shown in Fig. 1, contains a noise generator, which is a non-autonomous system of two coupled generators, and consists of generators 1, 2 and a coupling element 3 between them, a flat spiral antenna 4, a loop antenna of the magnetic dipole type 5 and a low-frequency noise source 6.

The generator 1 contains a nonlinear amplifier 7, a delay line 8 with a delay T and an inertial self-bias circuit 9, the output of a non-linear amplifier 7 is connected to its input through a delay line 8, an inertial auto-bias circuit 9 is connected between the common electrode of the active element and the common bus. The output of the generator 1 is connected to the input of the generator 2 using the communication element 3.

The generator 2 contains a non-linear amplifier 10 and an adjustable delay line 11, the output of the non-linear amplifier 10 is connected to the input through an adjustable delay line 11. The delay line 11 provides the ability to adjust the position of the natural frequencies of this generator.

Communication element 3 is a tee (branching modulo two Y), non-directional action, with step matching transformers.

A flat spiral antenna 4 is connected to the noise generator using a coupling element 3 — shoulder (s) and is a two-way spiral, each conductor of which has the form of an Archimedean (or logarithmic) spiral on a dielectric base.

The loop antenna 5 is a magnetic dipole, which is included in the power circuit of the second generator and through the antenna passes the total current of this generator. Thus, two antennas of various types are connected to the noise generator, which mutually complement each other with respect to the formation in space of the resulting electromagnetic noise field with given characteristics.

The low-frequency noise source 6 comprises a noise voltage source and an amplification-limiting device. The output of the low-frequency noise source is connected to the input of the first generator.

The radio masking device operates as follows.

(фиг.2,а). Нелинейные свойства активного элемента, инерционность и запаздывание сигнала в цепи обратной связи определяют сложную динамику колебаний генератора. Имеется область параметров, при которых в генераторе обеспечивается существование режимов с хаотической динамикой [11].The noise generator, which is the main component of the device under consideration, is a system of coupled generators with many degrees of freedom, the nature of the oscillations in which is determined by a combination of parameters such as the ratio of the oscillation frequencies of the partial generators, the magnitude of the connection between them, the operating mode, level and nature of the external influence. Generator 1 generates multi-frequency oscillations with spectral density maxima at natural frequencies, the interval between which is

(figure 2, a). The nonlinear properties of the active element, the inertia and the delay of the signal in the feedback circuit determine the complex dynamics of the oscillations of the generator. There is a region of parameters at which the existence of regimes with chaotic dynamics is ensured in the generator [11].

(фиг.2,б).Generator 2 also generates multi-frequency oscillations with spectral density maxima at their own frequencies, the interval between which

(figure 2, b).

When two generators work together, as a result of their interaction, the oscillation spectrum is enriched with additional components with an unequal arrangement of natural frequencies. The avalanche multiplication of the combination components of partial generators occurring in a coupled system and their nonlinear interaction leads to additional randomization of the oscillatory process through a sequence of period doubling bifurcations. Scenarios of transition to chaos may contain a different number of bifurcations depending on the totality of parameters [12].

Communication element 3, having an undirected action, creates the conditions for the interaction of generators 1 and 2 connected to it. By choosing the ratio of wave impedances (L, ρ) of the microstrip transformers of the communication element, the required frequency response of the noise generator in the operating frequency range is achieved.

To increase the stability of the regime of chaotic oscillations, a low-frequency noise source is introduced into the radio masking device 6. The effect of external low-frequency noise on the generators contributes to the destruction of synchronous oscillation modes and increases the stability of broadband noise, the band of which is determined by the system bandwidth (Fig.

Radiating antennas of a radio masking device converts the energy of electromagnetic waves of high frequency, concentrated in oscillatory circuits, into the energy of radio waves. A flat spiral antenna (Fig. 3, a, b), having a radiation pattern in the form of two wide petals (Fig. 3, c), forms a radiation field with circular polarization in the direction of the axis perpendicular to the plane of the antenna. The loop antenna (Fig. 3, d) forms a field in the form of a spherical wave with maxima in the equatorial plane (Fig. 3, d). The frequency independence of the antennas is based on the principle of electrodynamic similarity, i.e. a change in wavelength is accompanied by a proportional change in the linear dimensions of the active region of the antenna.

As an example of a specific implementation of the inventive device on figa shows a circuit diagram of a radio masking device. The noise generator is based on generators based on transistors VT4, VT5. The first generator on transistor VT4 contains a delayed feedback circuit L1 (T = 5.6 ns), made in the form of a microstrip line, and an inertial auto-bias circuit R11, C6. The interval between the natural frequencies of this generator is ~ 180 MHz. The second generator is made on transistor VT5 and contains an adjustable delayed feedback circuit L3, C7, C8 (T = 2.5 ÷ 3.0 ns). The interval between the natural frequencies of this generator can be adjusted by changing the capacitance of the capacitor C8 within 330 ÷ 400 MHz. The connection between the generators is carried out using a coupling element in the form of a tee with step matching transformers in microstrip design and capacitive decoupling in direct current using capacitors C5, C7, C8. As a low-frequency noise source, a VD1 noise diode is used, operating in avalanche mode of the rn junction and a three-stage amplifier-limiter based on VT1-VT3 transistors. The noise source generates a noise signal in the frequency band from units of kilohertz to 6 MHz. From the output of the VT3 transistor, a noise signal is fed to the input of generator 1. A certain selection of the time constant of the inertial auto-bias circuit R11, C6 and the delay time of the signals in the feedback circuits of these generators allows us to generate a broadband noise signal in the frequency band from 100 kHz to 2000 MHz.

The WA1 flat helical antenna is made by printing on a dielectric sheet with dimensions of 0.5 × 0.5 m. The two-way helix is formed by two identical tapes rotated 180 degrees relative to each other and connected to the noise generator using a coaxial cable. The WA2 loop antenna is made in the form of a single-turn conductor with a diameter of 0.6 meters. The optimal relative position of antennas 4 and 5 in space is the position when the plane of the loop antenna is located in the plane of the spiral antenna. In this case, the minimum field strengths of the loop antenna correspond to the maximum field values for the spiral antenna. The spatial distribution of the electromagnetic field generated by the antennas of the inventive radio masking device is shown in FIG. The curve (•) displays the radiation pattern of the spiral antenna, the curve (◇) - the frame. The resulting distribution in space of the electromagnetic field of the radio masking device with two antennas (magnetic dipole, helical antenna) when they work together is shown in Fig. 5 (solid line), at three frequencies of the operating range: a) 50 MHz, b) 500 MHz, c) - 1800 MHz. In conditions of rooms with many reflective surfaces, the antenna patterns are significantly distorted, however, analysis of the operation of the radio masking device with various types of antennas shows that the joint work of two antennas - helical and loop, gives the best results. At the same time, due to the superposition, the unevenness of the spectral density of the masking electromagnetic field is compensated due to the amplitude-frequency properties and radiation patterns of each of the antennas.

Structurally, the prototype radio masking device, made in accordance with the claimed invention, is a printed circuit board measuring 120 × 100 mm, which is located in a plastic case with a single-turn frame and flat helical antennas fixed to it. Power supply of the masking device is carried out from a direct current source (mains adapter) with a voltage of 12 V.

The resulting picture of a noise electromagnetic masking field formed in the surrounding space by the inventive radio masking device is shown in Fig.6. A graphical representation of the change in the spectral density of noise power versus frequency shows that the level of the masking signal is 13–18 dB higher than the level of informative spurious emissions of computer equipment in the entire PEMIN frequency range. The unevenness of the spectral density of the noise power of the masking electromagnetic field does not exceed 8 dB / octave, which provides better performance compared to the known analogues and prototype. In this case, the frequency range of the radio masking device, compared with the prototype, is increased to 2000 MHz, which meets the regulatory requirements [10] for active radio-technical masking (protection) of information at computer facilities of category 1-3.

Literature

1. Ivanov V.P., Lebedev M.N., Sak V.V. Radio-masking device for information radiation of CBT. - Information and methodological magazine “Information Protection. Confident, No. 1, 2001, p. 35-37.

2. Diduk L.I., Akinshina G.N. "Noise generator." Patent No. 2292109, Russia. Publication date 2007.01.20.

3. Oleinikov SV., Svetovidov VN “Broadband antenna system for spatial noise protection device" Octave-PC. " Utility Model No. 64835, Russia. Date of publication 2007.07.10.

4. Gorokhovatsky A.N., Zapletin Yu.V., Bezginov I.G. "A device for protecting computer technology from electromagnetic spurious emissions." Patent No. 2204882, Russia. Publication date 2003.05.20.

5. Bezrukov V. A., Ivanov V. P., Lebedev M. N. “Radio masking device”, Patent No. 2224376, Russia. Publication date 02/20/2004

6. Ivanov V.P., Lebedev M.N., Volkov A.I. “Radio masking device”, Utility model No. 38257, Russia. Publication date 2004.01.08, Bull. No. 15.

7. Lebedev M.N., Ivanov V.P. "Generators with chaotic dynamics." Instruments and experimental technique. - M .: Nauka, 2002, No. 2, pp. 94-99.

8. Bezrukov V.A., Ivanov V.P., Kalashnikov B.C., Lebedev M.N. "The device of radio masking." Patent No. 2170493, Russia, Date of publication 2001.07.10.

9. GOST R 50752-95. Information technology. Information protection against leakage due to spurious electromagnetic radiation during its processing by computer technology. Test methods.

10. Collection of standards for the protection of technical equipment from information leakage due to spurious emissions and interference. State Technical Commission of Russia, 1998

11. Kislov V.Ya. Dynamic chaos and its use for generating, receiving and processing oscillations and information. Radio engineering and electronics. 1993, T. 38. 10, pp. 1783-1815.

12. Dmitriev A.S., Kislov V.Ya. Stochastic oscillations in radiophysics and electronics. - M .: Science. 1989. S. 278.

Claims (1)

A radio masking device containing a noise generator, an active antenna circuit and a low-frequency noise source, in which the noise generator is made in the form of a system of two coupled generators, the first of them is a generator with delayed feedback and inertial auto-bias, the second generator is with adjustable delayed feedback, output the first generator is connected to the input of the second generator using a communication element, the active antenna circuit is made in the form of a magnetic dipole radiating frame antenna, one to which is connected to the output of the second generator, and the other to the common bus, the output of the low-frequency noise source is connected to the input of the first generator, characterized in that a flat spiral antenna is inserted into it, and the connection between the generators is carried out using the said communication element, which is non-directional tee with step matching transformers, the arm (a) of the communication element is connected to the output of the first generator, the arm (c) of the communication element is connected to the input of the second generator, arm (s) the communication element is connected to a flat spiral antenna.

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