RU2801874C1 - Transmitting system of high secrecy of setting with an automatic matching device using a broadband signal - Google Patents

Abstract

FIELD: radio engineering.

SUBSTANCE: invention can be used in shortwave (HF), ultrashortwave (UHF) radio stations, as well as in radio stations of other bands. To do this, the first (7.1) and second (7.2) level analysers (LA) are introduced into the device, and the high-frequency signal generator (1) – a broadband signal generator (BBSG) (10) and a modulator (11) connected in series, the output of the former is connected to one of the key inputs (3). The outputs of the first (7.1) and second (7.2) LAs are connected to the corresponding inputs of the tuning unit (6). The output of the branched voltage of the incident wave Ui of the bidirectional coupler (BDC) (5) is connected to the input of the first LA (7.1); the output of the branched voltage of the reflected wave Uref of the BDC (5) is connected to the input of the second level analyser (7.2).

EFFECT: increase in the secrecy of the transmitting device during the tuning of the transmitting path, understood as the distance from which the signal emitted at this time can be detected.

5 cl, 5 dwg

Description

The invention relates to radio engineering and can be used in shortwave (HF), ultrashortwave (VHF) radio stations, as well as in radio stations of other bands.

In radio communications, the issue of matching the antenna with the transmitter plays an important role. The task of matching is relevant for different ranges and is solved in various ways. Coordination of the antenna with the transmitter has a number of features for radio stations of the short wave (HF) range, which are actively used at present.

Radio transmitting devices are known, for example, published in Shahgildyan V.V., Karyakin V.L. Designing devices for generating and shaping signals in mobile communication systems: Textbook for universities. M: SOLON-Press, 2011. - 400 p. page 308 fig. 4.2, page 309 fig. 4.3. Also known is a radio transmitter published in Shahgildyan V.V., Shumilin V.S., Kozyrev V.B. and others, ed. V.V. Shahgildyan - 4th ed., revised. and additional - M .: Radio and communication, 2000 - 656 p. page 377 fig. 5.6. However, these radio transmitters are designed to operate on a matched load and do not have an antenna matching circuit.

A radio transmitting device is known, described in the article "The concept of matching radio transmitting devices with loads", T-Comm, No. 9-2013 p.127-131, in which special tuning circuits are introduced. The disadvantage of this device is the high level of radiation during tuning and, as a consequence, the low secrecy of the transmitting means. Under secrecy is understood the meaning defined in Borisov V. I., Zinchuk V. M., Limarev A. E., Mukhin N. P. Fundamentals of the theory of radio engineering systems. Textbook - Voronezh.: Voronezh Research Institute of Communications, 2003, p. 29, as the ability of a radio communication facility to resist the actions of electronic intelligence aimed at detecting signals, measuring parameters and determining the direction of their arrival. According to the statement given in the same source on page 30, secrecy can be determined by various indicators, but the detection range finds the widest application.

The closest analogue in technical essence to the proposed device is a device according to patent RU 2747564, H04B 1/02, H04 1/0458, H03H 7/40, H03H 11/30 taken as a prototype.

The layout of the prototype device is shown in Fig. 1, where it is indicated:

1 - high frequency generator (HFG);

2 - sinusoidal signal generator (GSS);

3 - key;

4 - power amplifier (PA);

5 - bidirectional coupler (DNO);

6 - tuning unit (BP);

9 - matching chain (CA);

8 - antenna (transmitting system load);

12 - two-channel radio receiver (RCD).

The prototype device contains a serially connected RF generator 1, a bidirectional coupler 5, a matching circuit 9 and an antenna 8. Moreover, the high-frequency signal generator 1 consists of a sinusoidal signal generator 2 and an amplifier 4, the outputs of which are connected to the corresponding inputs of the key 3, the output of which is the output of the MHF 1. The two outputs of the bidirectional coupler 5 are connected to the two inputs of the two-channel radio receiver 12, respectively. The two outputs of the two-channel radio receiver 12 are connected to the corresponding inputs of the tuner 6, the four outputs of which are connected to the four inputs of the matching circuit 9, respectively.

The prototype device works as follows.

In the tuning mode, the GSS signal 2 is used, which is fed through the key 3 to the DNO 5 and then through the DS 9 to the antenna 8. In this case, the GSS 2 generates a harmonic signal at a frequency f ₁ , at which transmission will be carried out in the future. Since the transmission path is mismatched in the initial state, incident and reflected waves are formed in it. As a result, a branched voltage of the incident and reflected power is supplied from the output of the DNO 5 to the inputs of the RPU 12: Up is the branched voltage of the incident power, and Uotr is the branched voltage of the reflected power. The two-channel radio receiver 12 is tuned to the useful signal reception frequency f ₁ and passes the harmonic signal at the frequency f ₁ without attenuation. PSU 6 will receive Up - the branched voltage of the incident power, and Uotr - the branched voltage of the reflected power at frequency f ₁ . In the tuning block 6, based on the values of Up and Uotr, as well as the phase between them, the values of the control voltages of the DS 9 are calculated. After that, the DS 9 transforms the complex resistance of the antenna 8 to the output of the high-frequency generator 1. The described sequence of events is repeated until until the tuning process comes to a steady state.

In the transmission mode, switching is performed by the key 3 of the power amplifier 4 to the DNO 5. Since the output impedances of the GSS 2 and PA 4 are the same, the PA 4 will transfer the output power to the matched load.

The disadvantage of the prototype device is that in the process of setting the secrecy of the transmitting means is small. The narrowband signal used during tuning is radiated into the air and can be detected and measured over a considerable distance and in a finite amount of time.

So, for example, suppose that tuning is carried out at a frequency f ₁ =1 MHz by a sinusoidal signal for a time T _n = 1 s. Let's assume that this signal enters the air with a power of P _n = 1 mW. According to the formula proposed in the book by Dolukhanov M.P. Propagation of radio waves. - M.: Soviet radio, 1972, 152 p., p. 11, (1.7), and having the following form

,

where E is the field strength, V/m; P is the radiated power of the transmitter, W; L is the distance to the radiating antenna, m, the field strength of the electromagnetic wave will decrease with distance.

Having hit the antenna of the receiver-detector, the signal is converted into the form of a voltage fluctuation, the effective value of which is calculated by the formula

, IN,

where E is the field strength of the electromagnetic wave; AF is the antenna factor of the receiving antenna. Let's take it AF=3.

Since a sinusoidal signal was received, the amplitude of the voltage that appeared at the output of the receiver antenna can be calculated by the formula

, IN,

After all the substitutions, the formula for calculating the amplitude of the signal at the output of the antenna of the receiving means will take the following form

, IN,

The law of voltage change at the output of the antenna over time is expressed in the following form:

, IN

If the receiver-detector receives in an optimal way, that is, it is a correlation receiver or a receiver based on a matched filter, then at the moment the tuning is completed, a voltage will appear at the correlator output having a level

, IN,

where s(t) is the signal voltage received from the air and appeared at the antenna output; s _op (t) - reference signal calculated by the formula

After integration and simplification, the function R(t) takes the following form

It is this value that will appear at the output of the optimal receiver-detector by the end of the tuning.

In the presence of an optimal receiver-detector of additive noise at the input, having a power spectral density N ₀ =1 μJ, the signal-to-noise ratio at the output of the correlator will be determined by the expression indicated in the book by V.I. Borisov, V.M. Zinchuk, A.E. Limarev, I.P. Mukhin, G.S. Nachmanson. Noise immunity of radio communication systems with the expansion of the spectrum of signals by modulation of the carrier pseudo-random sequence. -M.: Radio and communication, 2003 on p. 65 in the form of formula (1.4.17). Taking into account the fact that the expression obtained above for calculating R(t) is a correlation function, the value of which is the value of the signal energy at the time T _n , the above formula (1.4.17) takes the following form:

,

where N ₀ is the noise power spectral density.

Taking into account the values found above

,

whence the detection range is calculated by the formula

If we assume that the acceptable probability of false alarms of the receiver-detector is , then, according to the schedule given in the Fundamentals of the Theory of Radio Engineering Systems. Tutorial. // IN AND. Borisov, V.M. Zinchuk, E.L. Limarev, N.P. Mukhin. - Voronezh: Voronezh Research Institute of Communications, 2004 on p. 67, fig. 3.3 and shown in Fig. 2, the probability of detecting the signal emitted during tuning will be close to P _rev = 1 at the minimum value of the signal-to-noise ratio

.

The distance from which such a signal can be detected is

m

The objective of the proposed technical solution is to increase the secrecy of the transmitting means during the tuning of the transmitting path, understood as the distance from which the signal emitted at this time can be detected.

To solve the problem in a transmitting system of increased secrecy settings with an automatic matching device using a broadband signal, containing a series-connected high-frequency signal generator (HFS), a bidirectional coupler (DNO), a matching circuit (CS) and an antenna, and the HVS consists of a sinusoidal signal generator (GSS) and a power amplifier, the output of which is connected to one input of the key, the output of which is the output of the DHW, while the BOTTOM has outputs of the branched voltage of the incident Up and reflected Uot wave, as well as a tuning unit, the output of which is connected by a bus to the second input of the CS , according to invention , the first and second signal level analyzers (ANU) are introduced, and the high-frequency signal generator is connected in series with a broadband signal generator (GShPS) and a modulator, the output of which is connected to another input of the key; the output of the GSS is connected to the second input of the modulator; the outputs of the first and second ANU are connected to the corresponding inputs of the tuning block; the output of the branched voltage of the incident wave Up BOTTOM is connected to the input of the first ANU; the output of the branched voltage of the reflected wave Uotr DNO is connected to the input of the second signal level analyzer.

In FIG. 3 shows a diagram of the proposed device, where it is indicated:

1 - high-frequency signal generator (HWS);

2 - sinusoidal signal generator (GSS);

3 - key (Cl);

4 - power amplifier (PA);

5 - bidirectional coupler (DNO);

6 - tuning unit (BP);

7.1, 7.2 - the first and second signal level analyzers (ANU);

8 - antenna (transmitting system load)

9 - matching chain (CA);

10 - broadband signal generator (GShPS);

11 - modulator (M).

The proposed device contains a high-frequency signal generator (HFS) 1, a bidirectional coupler 5, a matching circuit 9 and an antenna 8 connected in series. Moreover, the HF signal generator 1 contains a broadband signal generator 10, the output of which is connected to the first input of the modulator 11, the output of the sinusoidal signal generator 2 connected to the second input of the modulator 11, the output of which is connected to the first input of the key 3, the second input of which is connected to the output of the power amplifier 4. In this case, the output of the key 3 is the output of the DHW 1. In addition, the output of the branched voltage of the incident wave Up BOTTOM 5 is connected to the input the first signal level analyzer ANU 7.1. The output of the branched voltage of the reflected wave Uotr DNO 5 is connected to the input of the second signal level analyzer ANU 7.2. The outputs of the first 7.1 and second 7.2 signal level analyzers are connected to the corresponding inputs of the tuning unit BP 6, the output of which is connected by a bus to the second input of the matching circuit CS 9.

The first 7.1 and second 7.2 signal level analyzers can be implemented as follows.

1. The first option, according to which the first 7.1 and 7.2 of the second ANU are identical, the construction scheme of the first and second ANU is shown in Fig. 4.

ANU contains a matched filter (SF) 7.1.1 and a clock generator (GSI) 7.1.2, the inputs of which are combined and are the input of the ANU. The outputs of the SF 7.1.1 and GSI 7.1.2 are connected to the corresponding inputs of the sample-hold device (SHA) 7.1.3, the output of which is the output of the ANU.

2. The second variant of constructing the identical first 7.1 and second 7.2 ANU is shown in FIG. 5.

The ANU contains a multiplier (Umn) 7.1.5, a synchronized pseudo-random sequence generator (GSPSP) 7.1.6, and a clock generator (GSI) 7.1.2, the inputs of which are combined and are the input of the ANU. At the same time, the output of the GSPSP 7.1.6 is connected to the second input of the multiplier 7.1.5, the output of which is connected through the integrator 7.1.4 to the first input of the sample-hold device 7.1.3, the output of which is the output of the ANU, in addition, the output of the GSI is connected to the second input UVH 7.1.3.

3. According to the third option, the first ANU 7.1 is assembled according to the scheme shown in FIG. 4, and the second ANU 7.2 - according to the scheme shown in Fig. 5.

4. According to the fourth version, the first ANU 7.1 is assembled according to the scheme shown in FIG. 5, and the second ANU 7.2 - according to the scheme shown in Fig. 4.

The proposed device works as follows.

In the tuning mode, a broadband signal is used that appears at the output of the modulator 11, which is fed through the key 3 to the DNO 5 and then through the DS 9 to the antenna 8. The modulator 11 generates a broadband signal by changing the parameter of the sinusoidal signal generated by the GSS 2 according to the law specified by the GShPS 10 In this case, the broadband signal has a center frequency equal to the tuning frequency f ₁ , at which transmission will be performed in the future. As a result, from the outputs of the DNO 5 to the first ANU 7.1 and the second ANU 7.2, the branched voltage of the incident and reflected waves, respectively: Up - branched voltage of the incident wave, and Uref - branched voltage of the reflected wave.

Further, according to the first variant of building signal level analyzers inside the first ANU 7.1, whose block diagram is built on the basis of a matched filter and is shown in Fig. 4, the input signal (In) is fed to the input of the matched filter SF 7.1.1 and the clock generator GSI 7.1.2. The response of the matched filter SF 7.1.1 follows the first input of the SHA 7.1.3 sample-and-hold device, which, by the pulses arriving at its second input from the clock generator GSI 7.1.2, remembers the output signal level of the matched filter SF 7.1.1 and outputs it to the output of the first ANU 7.1. The clock generator 7.1.2 generates pulses that lead to storing the input signal level SHA 7.1.3, at those moments in which the response of the matched filter SF 7.1.1 to the input signal takes the maximum value. As a result, a signal appears at the output of SHA 7.1.3, the level of which is proportional to the level of the input signal.

Processes running in the second ANU signal level analyzer 7.2. for the first option are similar to the processes described above, occurring in the first signal level analyzer ANU 7.1.

According to the second option, the first and second signal level analyzers ANU 7.1 and ANU 7.2 are built according to the scheme with a correlator shown in Fig. 5. The correlator is formed by the multiplier 7.1.5 and the integrator 7.1.4. The first input of the multiplier 7.1.5 receives the input signal ANU 7.2. The second input of the multiplier 7.1.5 receives the reference signal, which is generated by the generator of a synchronized pseudo-random sequence 7.1.6. The synchronization process is carried out by GSPSP 7.1.6 by analyzing the input signal.

The output signal of the multiplier 7.1.5 is integrated using the integrator 7.1.4, after which it enters the first input of the sample-hold device 7.1.3, which remembers the maximum value of the correlation function received from the output of the integrator 7.1.4, and outputs it to the output, which is also the output of ANU. The moments at which UVH 7.1.3 stores the value of the signal coming from the output of the 7.1.4 integrator are determined by the pulses arriving at the second input of the sample-hold device UVH 7.1.3 from the output of the GSI 7.1.2. The clock generator 7.1.2 selects the timing of the supply of clock pulses to the second input of the sample-hold device 7.1.3 by analyzing the input signal received at the input of the ANU signal level analyzer.

As a result, a signal appears at the output of the SHA 7.1.3 sample-and-hold device, the level of which is proportional to the level of the input signal.

According to the third option, the first ANU 7.1 is assembled according to the scheme shown in Fig. 4. Its operation is described in detail above when considering the operation of signal level analyzers according to the first option. The second ANU 7.2 is assembled according to the scheme shown in Fig. 5. Its operation is described in detail above when considering the operation of signal level analyzers according to the second option.

According to the fourth version, the second ANU 7.2 is assembled according to the scheme shown in Fig. 4. Its operation is described in detail above when considering the operation of signal level analyzers according to the first option. The first ANU 7.1 is assembled according to the scheme shown in Fig. 5. Its operation is described in detail above when considering the operation of signal level analyzers according to the second option.

Tuning unit 6, based on the response values that appear at the outputs of the first 7.1 and second 7.2 ANU, calculates the direction and magnitude of the change in the parameters of the elements of the DS 9 and produces the appropriate control action on them, thereby approaching the satisfaction of the main criterion for the successful completion of the setting, which is maximizing the response from the output of the first ANU 7.1, while minimizing the response from the output of the second ANU 7.2.

In transmission mode, using key 3, the output of power amplifier 4 is connected to the input of bidirectional coupler 5, and the output of modulator 11 is turned off. Since the output impedances of the modulator 11 and PA 4 are the same, the power amplifier 4 will transfer the output power to the matched load.

The construction of blocks 2, 3, 4, 5, 6, 9, 8 in the claimed device is well known and similar to the implementation of blocks 2, 3, 4, 5, 6, 9, 8 of the prototype device, respectively.

The broadband signal generator GSHPS 10 can be assembled as a pseudo-random sequence generator, for example, in the form of an M-sequence generator described in the book Varakin L. E. Communication systems with noise-like signals. - M.: Radio and communication, 1985. -384 p. rice. 3.17, page 54.

As a modulator 11 can be used the device described in the book Sokolinsky VG, Sheinkman VG Frequency and phase modulators and manipulators. - M.: Radio and communication, 1983. -192 p., fig. 6.1a, p. 117.

The sample-hold device 7.1.3 is assembled according to the scheme given in "Analog-to-digital conversion". Ed. W. Kester - M.: Technosfera, 2007. - 1006 s in fig. 7.115 on page 607.

As a clock generator 7.1.2 from the signal level analyzers 7.1 and 7.2 shown in FIG. 4 and FIG. 5, the device described in "Immunity of radio communication systems with the expansion of the spectrum of signals by modulation of the pseudo-random carrier sequence"// V.I. Borisov, V.M. Zinchuk, A.E. Limarev, N.P. Mukhin, G.S. Nachmanson. - M.: Radio and communication, 2003. - 640 p. on page 448, fig. 9.9.

The synchronized pseudo-random sequence generator of the signal level analyzers 7.1 and 7.2 shown in FIG. 5 can be built according to the scheme given in the book Prokis D. Digital communication. - M.: Radio and communication, 2000, - 800 p. on page 645, fig. 13.5.5.

Thus, in the proposed system, an increase in the secrecy of the transmitting means during tuning has been achieved by introducing a broadband signal generator and a modulator into the GWS, as well as connecting the outputs of the incident and reflected waves of a bidirectional coupler to the inputs of signal level analyzers assembled on the basis of correlators and / or matched filters , the response maximum of which is fixed with the help of sample-hold devices and fed to the tuning unit for analysis.

The gain is achieved due to the fact that the signal energy during tuning is distributed over a wide range of frequencies. Only a small part of this signal will fall into the passband of a narrowband receiver. So, for example, if a signal based on the M-sequence with base B _s =16383 is used as a broadband signal, then the signal energy in the narrow band will also decrease by B _s times.

Then the signal-to-noise ratio becomes

,

and the conclusions of the formulas, similar to those carried out in determining the stealth of the prototype device, give an expression for the detection range when emitted by a broadband signal in the form

The ratio of the detection range when tuning with a narrow-band signal L to the detection range when tuning with a broadband signal L _W will be the value

For the example under consideration, the detection range was reduced from L=122.5 km to L _W =7.5 _m .

The achieved technical result is an increase in the secrecy of the transmitting means during the tuning of the transmitting path, understood as the distance from which the signal emitted at this time can be detected.

Claims (5)

1. Transmitting system of increased secrecy settings with an automatic matching device using a broadband signal, containing a series-connected high-frequency signal generator (HFS), a bidirectional coupler (DNO), a matching circuit (CS) and an antenna, and the HVS consists of a sinusoidal signal generator (GSS) and a power amplifier, the output of which is connected to one input of the key, the output of which is the output of the DHW, while the BOTTOM has outputs of the branched voltage of the incident Up and reflected Uref waves, as well as a tuning unit, the output of which is connected by a bus to the second input of the DS, characterized in that the first and second signal level analyzers (ANU) are introduced, and the high-frequency signal generator is connected in series with a broadband signal generator (GSPS) and a modulator, the output of which is connected to another key input; the output of the GSS is connected to the second input of the modulator; the outputs of the first and second ANU are connected to the corresponding inputs of the tuning block; the output of the branched voltage of the incident wave Up BOTTOM is connected to the input of the first ANU; the output of the branched voltage of the reflected wave Uotr DNO is connected to the input of the second level analyzer. 2. The transmission system according to claim 1, characterized in that the first and second level analyzers are identical and contain a matched filter (SF) and a clock generator (GSI), the inputs of which are combined and are the input of the ANU, the outputs of the SF and GSI are connected to the corresponding inputs of the device sample-hold, the output of which is the output of the ANU. 3. The transmission system according to claim 1, characterized in that the first and second level analyzers are identical and contain a multiplier, a synchronized pseudo-random sequence generator (GSPSP) and a clock generator (GSI), the inputs of which are combined and are the input of the ANU, while the output of the GSPSP is connected with the second input of the multiplier, the output of which is connected through the integrator to the first input of the sample-and-hold device (SHA), the output of which is the output of the ANU, in addition, the GSI output is connected to the second input of the SHA. 4. The transmission system according to claim 1, characterized in that the first level analyzer contains a matched filter (SF) and a clock generator (GSI), the inputs of which are combined and are the input of the first ANU, the outputs of the SF and GSI are connected to the corresponding inputs of the sample-storage device , whose output is the output of the first ANU; the second ANU contains a multiplier, a synchronized pseudo-random sequence generator (GPRSS) and a clock generator (GSI), the inputs of which are combined and are the input of the second ANU, while the output of the GPRSP is connected to the second input of the multiplier, the output of which is connected through the integrator to the first input of the sample-and-hold device (SWH), the output of which is the output of the second ANU, in addition, the HSI output is connected to the second SWH input. 5. The transmission system according to claim. 1, characterized in that the first level analyzer contains a multiplier, a synchronized pseudo-random sequence generator (GSPSP) and a clock generator (GSI), the inputs of which are combined and are the input of the first ANU, while the output of the GSPSP is connected to the second input a multiplier, the output of which is connected through the integrator to the first input of the sample-and-hold device (SHA), the output of which is the output of the first ANU, in addition, the GSI output is connected to the second input of the SHA; the second ANU contains a matched filter (SF) and a clock generator (GSI), the inputs of which are combined and are the input of the second ANU, the outputs of the SF and GSI are connected to the corresponding inputs of the sample-and-hold device, the output of which is the output of the second ANU.

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