RU2330295C1 - Method of frequency determination and device for its implementation - Google Patents

Abstract

FIELD: radio electronics.

SUBSTANCE: device contains receiving antenna 1, inlet circuit 2, searching unit 3, high frequency amplifier 4, heterodyne 5, mixer 6, intermediate frequency amplifier 7, detector 8, video amplifier 9, device of frequency sweep formation 10, CRT 11, video pulse shaper 12, first 13, second 27 and third 28 switches, generator 14 of intermediate frequency, multiplier 15, filter of summary frequency 16, amplitude modulator 17, noise generator 18, power amplifier 19, transmitting antenna 20, detector 21 of complex amplitude manipulation-phase manipulation - signals, first 22 and second 25 spectrum analysers, doubler 23 of phase, first 24 and second 34 narrow-band filters, comparison unit 26, first 29 and second 32 amplitude multipliers-limiters, synchronous detector 30, registration unit 31, divider 33 of phase into two, phase detector 35, shaper 36 of distorted modulated code and phase manipulator 37.

EFFECT: expansion of functional resources of method and device by means of detection of complex signals with combined amplitude modulation and phase manipulation, determination of their parameters and formation of target noise interference for radio-electronic suppression of wide-band communication systems.

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Description

The proposed method and device relate to the field of radio electronics and can be used to determine the carrier frequency and other parameters of complex signals with combined amplitude modulation and phase shift keying (AM-PSK) received in a given frequency range, and create aimed noise interference at this frequency to wideband systems communication.

Known methods for determining the frequency and device for their implementation (ed. Certificate of the USSR No. 524138, 620907, 868614, 1000930, 1012152, 1180804, 1187095, 1272266, 1290192, 1354124; RF patents No. 2124216, 2230330, 2280257; US patent No. 4443801; Vakin S.A., Shustov L.N. Fundamentals of Radio Countermeasures and Radio Engineering Intelligence (Moscow: Sov. Radio, 1968, p. 386-396, Fig. 10.3 and others).

Of the known methods and devices closest to the proposed are the "Method for determining the frequency and device for its implementation" (RF patent No. 2280257, G01R 23/00, 2005), which are selected as prototypes.

The aforementioned method and device provide the determination of only the carrier frequency of the received signal and allow the formation of an impact noise interference at this frequency for electronic suppression of electronic means (RES).

At present, broadband communication systems using complex signals with combined amplitude modulation and phase shift keying (AM-PSK) are widely used. The properties inherent in these signals make them promising, first of all, for ensuring the operation of broadband communication systems “under the interference”, for separating AM-PSK signals in shape when they work in a common section of a given frequency range.

From the point of view of detection, complex AM-QPSK signals have high energy and structural secrecy.

The energy secrecy of these signals is due to their high compressibility in time and spectrum with optimal processing, which reduces the instantaneous radiated power. As a result, the complex AM-QPSK signal at the receiving point may be masked by noise and interference. Moreover, the energy of a complex AM-QPSK signal is by no means small; it is simply distributed over the time-frequency domain so that at each point of this region the signal power is less than the noise and interference power.

The structural secrecy of complex AM-QPSK signals is due to a wide variety of their forms and significant ranges of parameter changes, which makes it difficult to optimize or at least quasi-optimal processing of complex AM-QPSK signals of an a priori unknown structure in order to increase the sensitivity of the receiver.

An object of the invention is to expand the functionality of the method and device by detecting complex signals with combined amplitude modulation and phase shift keying, determining their parameters and generating targeted noise interference for electronic suppression of broadband communication systems.

The problem is solved in that the method of determining the frequency, based, in accordance with the closest analogue, on the search for signals in a given frequency range by tuning the superheterodyne receiver, forming a frequency sweep on the screen of the cathode ray tube, converting the frequency of the received signal, amplifying it by voltage detection and supply to the vertically deflecting plate of the tube, as a result, a pulse is generated on the screen, according to the position of which the frequency carrier is determined on the frequency sweep the received signal, in this case, in the capture mode, a single video pulse is generated, the superheterodyne receiver is tuned for a time equal to the duration of the video pulse, an intermediate frequency voltage is generated, it is multiplied with the local oscillator voltage, the total frequency voltage is isolated and its amplitude modulated by noise, differs from the nearest analogue by doubling the phase of the received signal at the intermediate frequency, isolating the voltage at twice the intermediate frequency, measuring the spectrum width of the received signal at the intermediate frequency and its second harmonic, they are compared with each other and, if they are significantly different, they decide to detect a complex signal with combined amplitude modulation and phase manipulation, to detect it and further process it, for this, the detected signal is amplified and limited in amplitude, thereby forming a complex signal with phase shift keying, synchronously detecting the detected signal with combined amplitude modulation and phase shift keying By means of this, a low-frequency voltage is proportional to the modulating function of the amplitude modulation, and it is recorded, amplified and limited in amplitude by the voltage of the double intermediate frequency, its phase is divided into two, the harmonic voltage of the intermediate frequency is isolated, it is used for phase detection of a complex signal with phase manipulation, isolated a low-frequency voltage proportional to the modulating code, for which the duration of the elementary packages τ _e , register it, form a distorted mode A validating code whose elementary duration τ _and = 2 · τ _e manipulate it with the voltage phase of the total frequency with noise amplitude modulation, generate a complex signal with combined noise amplitude modulation and distorted phase manipulation, amplify it in power and radiate it as targeted relay interference of a broadband communication system.

The problem is solved in that the device for determining the frequency, containing, according to the closest analogue, a series-connected receiving antenna, an input circuit, a high-frequency amplifier, a mixer, the second input of which is connected to the local oscillator output, and an intermediate-frequency amplifier, a series-connected detector, video amplifier and vertical deflecting plates of a cathode ray tube, horizontal deflecting plates of which are connected to the output of the frequency sweep forming device, a follower о a video pulse shaper connected to the detector output, the first key, the second input of which is connected to the second output of the local oscillator, a multiplier, the second input of which is connected to the output of the intermediate frequency generator, a total frequency filter and an amplitude modulator, the second input of which is connected to the output of the noise generator, a power amplifier and a transmitting antenna, while the control inputs of the input circuit, a high frequency amplifier, a local oscillator, and a frequency sweep shaping device are connected to The corresponding outputs of the search unit, the control input of which is connected to the output of the video pulse shaper, differs from the closest analogue in that it is equipped with a phase doubler, two spectrum analyzers, two narrow-band filters, a comparison unit, second and third keys, a phase divider into two, and two amplitude amplifiers -limiters, a synchronous detector, a registration unit, a phase detector, a shaper of a distorted modulating code and a phase manipulator, and to the output of the amplifier is an intermediate part a phase doubler, a first narrow-band filter, a second spectrum analyzer, a comparison unit, the second input of which is connected through the first spectrum analyzer to the output of the intermediate frequency amplifier, and a second switch, the second input of which is connected to the output of the intermediate frequency amplifier, and the output is connected to the input, in series detector, the third key is connected to the output of the second key, the second input of which is connected to the output of the video pulse shaper, the first amplitude amplifier-limiter, synchronous det a ctor, the second input of which is connected to the output of the third key, and the registration unit, to the output of the first narrow-band filter, a second amplitude amplifier-limiter, a phase divider into two, a second narrow-band filter, a phase detector, the second input of which is connected to the output of the first amplitude amplifier, are connected in series a limiter, a shaper of a distorted modulating code and a phase manipulator, the input of which is connected to the output of the amplitude modulator, and the output is connected to the input of the power amplifier, the second input of the reg tration connected to the output of the phase detector.

The structural diagram of a device that implements the proposed method is presented in figure 1. Timing and frequency diagrams explaining the operation of the device shown in figure 2, 3 and 4.

The device contains a receiving antenna 1 connected in series, an input circuit 2, a high-frequency amplifier 4, a mixer 6, the second input of which is connected to the local oscillator 5 output, an intermediate-frequency amplifier 7, a phase doubler 23, a first narrow-band filter 24, a second spectrum analyzer 25, block 26 comparison, the second input of which through the first spectrum analyzer 22 is connected to the output of the intermediate frequency amplifier 7, the second key 27, the second input of which is connected to the output of the intermediate frequency amplifier 7, detector 8, video amplifier 9 and vertically -otklonyayuschie plate cathode ray tube (CRT) 11, a horizontally deflecting plates which are connected to the output device 10 of the frequency sweep. The control inputs of the input circuit 2, high-frequency amplifier 4, local oscillator 5 and frequency sweep forming device 10 are connected to the corresponding outputs of the search unit 3, for which a sawtooth voltage generator can be used, the control input of which is connected to the output of the video pulse shaper 12. A video pulse former 12 is connected to the output of the detector 8, the first key 13, the second input of which is connected to the second output of the local oscillator 5, the multiplier 15, the second input of which is connected to the output of the intermediate frequency generator 14, the filter 16 of the total frequency, the amplitude modulator 17, the second input of which connected to the output of the noise generator 18, a phase manipulator 37, a power amplifier 19 and a transmitting antenna 20. A third key 28 is connected to the output of the second key 27, the second input of which is connected to the output of the of the video pulse 12, a first amplitude amplifier-limiter 29, a synchronous detector 30, the second input of which is connected to the output of the third key 28, and a recording unit 31, the second input of which is connected to the output of the phase detector 35. A second amplitude amplifier is connected in series to the output of the first narrow-band filter 24 limiter amplifier 32, two phase divider 33, second narrow-band filter 34, phase detector 35, the second input of which is connected to the output of the first amplitude limiter amplifier 29, and distorted module former 36 a code, the output of which is connected to the second input of the phase manipulator 37. Spectrum analyzers 22 and 25, a phase doubler 23, a first narrow-band filter 24 and a comparison unit 26 form a detector of a complex AM-QPSK signal.

The proposed method is implemented by a device that operates as follows.

The search for complex AM-QPSK signals in a given frequency range Df is carried out using the search unit 3, which, according to a sawtooth law, consistently changes the setting of the input circuit 2, high-frequency amplifier 4 and local oscillator 5. At the same time, the search unit 3 controls the frequency sweep generation device 10 on the screen CRT 11.

Received complex signal with combined amplitude modulation and phase shift keying (AM-PSK)

U _c (t) = υ _s [1 + m (t)] · Cos [ω _c t + φ _к (t) + φ _c ], 0≤t≤T _c ,

where υ _c , ω _s , φ _c , T _s - amplitude, carrier frequency, initial phase and signal duration;

m (t) is a modulating function that displays the law of amplitude modulation (figure 4, a);

_to φ (t) = {0, π} - phase component of the manipulated showing law phase shift keying in accordance with the modulating code M (t) (Figure 4, b) _to said φ (t) = const when k · τ _e < t <(k + 1) · τ _e and can change abruptly at t = k · τ _e , i.e. at the boundaries between elementary premises (k = 1, 2, ..., N);

τ _e , N - the duration and number of chips that make up a signal of duration T _s (T _s = τ _e · N),

from the output of the receiving antenna 1 through the input circuit 2 and the high-frequency amplifier 4 is fed to the first input of the mixer 6, the second input of which is fed the voltage of the local oscillator 5 of a ramp frequency (figure 2)

U _g (t) = υ _g Cos (ω _g t + πγt ² + φ _g ), 0≤t≤T _p ,

where υ _g , ω _g , φ _g , T _p - amplitude, initial frequency, initial phase and the repetition period of the local oscillator voltage;

γ = Df / T _p is the rate of change of the local oscillator frequency.

At the output of the mixer 6, voltages of combination frequencies are generated. Amplifier 7 is allocated voltage intermediate (differential) frequency

U _pr (t) = υ _pr [1 + m (t)] · Cos [ω _pr t + φ _k (t) -πγt ² + φ _pr ], 0≤t≤T _s ,

where υ _pr = 1/2 · υ _c υ _g ;

ω _CR = ω _c -ω _g is the intermediate frequency;

φ _CR = φ _c -φ _g ,

which is a complex signal with combined amplitude modulation, phase shift keying and linear frequency modulation (AM-PSK - LUM). This voltage is supplied to the input of the detector 21 of a complex AM-QPSK signal, consisting of spectrum analyzers 22 and 25, a phase doubler 23, a narrow-band filter 24, and a comparison unit 26.

A voltage is generated at the output of the phase doubler 23

U ₁ (t) = υ ₁ [1 + m (t)] ² · Cos (2ω _pr t-2πγt ² + φ _pr ),

where υ ₁ = υ _pr ² .

As a phase doubler 23, a multiplier can be used, the two signal of which receives the same signal U _pr (t).

Since 2φ _к (t) = {0, 2π}, phase manipulation is already absent in the indicated voltage.

The width of the spectrum Δf _{2 of the} second harmonic is determined by the duration T _{s of the} signal (Δf ₂ = 1 / T _s ), while the width of the spectrum Δf _{c of a} complex AM-FMN signal is determined by the duration τ _{e of} its elementary premises (Δf _c = 1 / τ _e ), those. the width of the spectrum Δf _{2 of the} second harmonic of the signal is N times smaller than the width of the spectrum Δf _{c of the} input signal (Δf _c / Δf ₂ = N).

Therefore, when the phase of a complex AM-QPSK signal is doubled, its spectrum “folds” N times. This circumstance makes it possible to detect a complex AM-QPSK signal even when its power at the input of the superheterodyne receiver is less than the power of interference and noise.

The width of the spectrum Δf _{c of the} input AM-QPSK signal is measured using the spectrum analyzer 22, and the spectrum width Δf _{2 of the} second harmonic of the signal is measured using the spectrum analyzer 25. Voltages U _I and U _II , proportional to Δf _c and Δf ₂ , are supplied to the two inputs of the comparison unit 26. Since U _I >> U _II , a constant voltage is generated at the output of the comparison unit 26, which is supplied to the control input of the key 27, opening it. In the initial state, keys 13, 27 and 28 are always closed.

The voltage U _CR (t) from the output of the intermediate frequency amplifier 7 through the public key 27 is fed to the input of the detector 8. After detection in the detector 8, the signal envelope is additionally amplified in the video amplifier 9 and fed to the vertical-deflecting plates of the CRT 11, as a result of which a pulse (frequency mark) is formed on the screen, the position of which on the frequency sweep determines the carrier frequency ω _{from the} received signal.

It should be noted that in the search mode, to ensure a high probability of signal interception, the speed at the tuning of the local oscillator 5 is chosen slow enough so that the interception can be carried out in one frequency tuning cycle. Tuning continues until a complex AM-QPSK signal is detected in the passband Δω _{p of the} intermediate frequency amplifier 7.

In capture mode, the detected signal is supplied to the driver 12, which generates a single video pulse of duration T _and (Fig. 2). This video pulse arrives at the control inputs of the keys 13 and 28, opening them, and at the control input of the search unit 3, stopping the tuning of the superheterodyne receiver for the time T _and .

At the same time, the following voltage is generated at the output of the intermediate frequency amplifier 7 (Fig. 4 c)

U _pr1 (t) = υ _pr [1 + m (t)] · Cos [ω _pr t + φ _к (t) + φ _pr ], 0≤t≤T _s ,

which through public keys 27 and 28 is fed to the first (information) input of the synchronous detector 30 and to the input of the first amplitude amplifier-limiter 29, the output of which is generated voltage (Fig. 4, d)

_Np2 U (t) = υ _a · Cos [ω t + φ _{forth in} (t) + φ _etc.] 0≤t≤T _s,

where υ _o is the limit threshold.

This voltage is a complex QPSK signal at an intermediate frequency and is supplied as a reference voltage to the second (reference) input of the synchronous detector 30. As a result of synchronous detection, a low-frequency voltage is generated at the output of the synchronous detector 30 (Fig. 4, e)

U _n1 (t) = υ _n1 [1 + m (t)], 0≤t≤T _s ,

υ where _H1 = 1/2 · υ _{pr o} υ,

proportional to the modulating function m (t) (Fig. 4, a). This voltage is detected by the registration unit 31.

Voltage U ₂ (t) from the output of the phase doubler

U ₂ (t) = υ ₁ [1 + m (t)] ² · Cos (2ω _pr t + 2φ _pr ),

allocated by a narrow-band filter 24 and is fed to the input of the second amplitude amplifier-limiter 32, the output of which a voltage is generated (figure 4, e)

U ₃ (t) = υ _о · Cos (2ω _pr t + 2φ _pr ), 0≤t≤T _s .

This voltage is fed to the input of the phase divider 33 into two, the output of which is formed by a harmonic voltage (figure 4, g)

₄ U (t) = υ _a · Cos (ω t + φ _{pr pr),} 0≤t≤T _p.

This voltage is allocated by the second narrow-band filter 34, used as a reference voltage and fed to the second (reference) input of the phase detector 35, to the first (information) input of which a complex PSK signal U _pr2 (t) is _supplied (Fig. 4, d) s the output of the first amplitude amplifier-limiter 29. As a result of phase detection, a low-frequency voltage is generated at the output of the phase detector 35 (Fig. 4, h)

U _n2 (t) = υ _n2 · _{Cosφ to} (t), 0≤t≤T _s ,

where υ _Н2 = 1/2 · υ _о ² ,

proportional to the modulating code M (t) (Fig. 4, b). This voltage is fixed registration unit 31 and supplied to the input of the 36 distorted baseband code _and M (t) (Figure 4, u), which chip duration τ = 2 _{and e} · τ.

The voltage of the local oscillator 5

U _g1 (t) = υ _g Cos (ω _g t + φ _g ),

from the second output through the public key 13 is fed to the first input of the multiplier 15, the second input of which is supplied with an intermediate frequency voltage from the output of the generator 14

₅ U (t) = υ ₅ · Cos (ω t + φ _{pr pr).}

The output of the multiplier 15 produces the following voltage

U ₆ (t) = υ ₆ · Cos [(ω _pr + ω _g ) t + φ _pr + φ _g ] + υ ₆ · Cos [(ω _g- ω _pr ) t + φ _g- φ _pr ], 0≤ t≤T _c ,

₆ where υ = 1/2 · υ υ _{5 g.}

From this voltage, the filter 16 of the total frequency is allocated voltage

U _∑ (t) = υ ₆ · Cos [(ω _pr + ω _g ) t + φ _pr + φ _g ] = υ ₆ · Cos (ω _c t + ω _s ),

which is supplied to the first input of the amplitude modulator 17. The noise voltage from the output of the noise generator 18 is supplied to the second input of the amplitude modulator 17. The output of the amplitude modulator 17 produces an amplitude-modulated signal

U ₇ (t) = υ ₆ [1 + m _w (t)] · Cos (ω _c t + φ _s ), 0≤t≤T _s ,

where m _w (t) is the modulating noise function,

which is fed to the first input of the phase manipulator 37. A distorted modulating code M _AND (1) (Fig. 4, i) is supplied to the second input of the phase manipulator 37 from the output of the driver 36. A complex signal with combined amplitude noise modulation is generated at the output of the phase manipulator 37 distorted phase shift keying (AM-PSK) (figure 4, k)

U ₈ (t) = υ ₆ [1 + m _w (t)] · Cos [ω _with t + φ _ki (t) + φ _c ], 0≤t≤T _s ,

where φ _ki (t) = {0, π} is the manipulated phase component that displays the phase manipulation law in accordance with the modulating code M _AND (t) (Fig. 4, i), and φ _ki (t) = const for k ₁ · Τ _and <t <(k ₁ +1) τ _and and can change stepwise at t = k ₁ · τ _and , i.e. at the boundaries between elementary premises (k ₁ = 1, 2, ..., N ₁ );

τ _and , N ₁ - the duration and number of chips that make up a signal of duration T _s (T _s = τ _and · N ₁ ).

This signal, after amplification in the power amplifier 19, is radiated by the transmitting antenna 20 into the air as a targeted relay interference of a broadband communication line.

After the time T _{, the} tuning of the superheterodyne receiver and the search for complex AM-QPSK signals continue. When the next AM-QPSK signal is detected, the device operates in a similar way.

Thus, the proposed method and device in comparison with the prototypes not only determine the carrier frequency of the reconnaissance radio electronic equipment, but also allow you to detect complex signals with combined amplitude modulation and phase shift keying, determine and record their parameters, generate impact interference with noise amplitude modulation and distorted phase manipulation as relayed interference for a broadband communication system.

Thus, the functionality of the method and device is expanded.

Claims (2)

1. A method for determining the frequency based on the search for signals in a given frequency range by tuning the superheterodyne receiver, forming a frequency sweep on the cathode ray tube screen, converting the received signal by the frequency, amplifying it by voltage, detecting and applying to the vertically-deflecting tube plates, as a result an impulse is formed on the screen, by the position of which the carrier frequency of the received signal is determined on the frequency sweep, while in the capture mode they form a single form an impulse, stop tuning the superheterodyne receiver for a time equal to the duration of the video pulse, form an intermediate frequency voltage, multiply it with the local oscillator voltage, isolate the voltage of the total frequency and modulate it in amplitude with noise, characterized in that the phase of the received signal is doubled at the intermediate frequency, the voltage is isolated by doubled intermediate frequency, measure the spectrum width of the received signal at the intermediate frequency and its second harmonic, compare them with each other if they are significantly different, they decide to detect a complex signal with combined amplitude modulation and phase manipulation, to detect it and further process it, for this purpose, the detected signal is amplified and limited in amplitude, thereby forming a complex signal with phase manipulation, and synchronously detect the detected signal with combined amplitude modulation and phase shift keying, emit a low-frequency voltage proportional to the modulating function of the amplitude odulation, and record it, amplify and limit the voltage of the doubled intermediate frequency in amplitude, divide its phase into two, isolate the harmonic voltage of the intermediate frequency, use it for phase detection of a complex signal with phase shift keying, isolate a low-frequency voltage proportional to the modulating code, for which the duration elementary premises τ _e , register it, form a distorted modulating code for which the duration of elementary premises τ _and = 2 * τ _e , manipulate it with the phase total frequency oscillations with noise amplitude modulation form a complex signal with combined noise amplitude modulation and distorted phase shift keying, amplify it in power and radiate it as a targeted relayed interference to a broadband communication system. 2. A device for determining the frequency, containing a series-connected receiving antenna, an input circuit, a high-frequency amplifier, a mixer, the second input of which is connected to the local oscillator output, and an intermediate-frequency amplifier, a series-connected detector, video amplifier, and vertical-deflecting plates of a cathode ray tube, the horizontal deflecting plates of which are connected to the output of the frequency sweep forming device, the video pulse shaper is connected in series to the output of the detector, the first key, the second input of which is connected to the second output of the local oscillator, a multiplier, the second input of which is connected to the output of the intermediate frequency generator, a total frequency filter and an amplitude modulator, the second input of which is connected to the output of the noise generator, a power amplifier and a transmitting antenna connected in series, while the control inputs of the input circuit, high-frequency amplifier, local oscillator and frequency sweep forming device are connected to the corresponding outputs of the search unit, the control input of which о is connected to the output of the video pulse shaper, characterized in that it is equipped with a phase doubler, two spectrum analyzers, two narrow-band filters, a comparison unit, second and third keys, a phase divider into two, two amplitude limiters, a synchronous detector, a recording unit, a phase a detector, a shaper of a distorted modulating code and a phase manipulator, moreover, a phase doubler, a first narrow-band filter, a second a are connected to the output of the intermediate frequency amplifier a spectrum analyzer, a comparison unit, the second input of which is connected to the output of the intermediate frequency amplifier through the first spectrum analyzer, and the second key, the second input of which is connected to the output of the intermediate frequency amplifier, and the output is connected to the detector input, the third key is connected in series to the output of the second key, the second input of which is connected to the output of the driver of the video pulse, the first amplitude amplifier-limiter, a synchronous detector, the second input of which is connected to the output of the third key, and the registration unit, to during the first narrow-band filter, a second amplitude amplifier-limiter, a phase divider into two, a second narrow-band filter, a phase detector, the second input of which is connected to the output of the first amplitude amplifier-limiter, a shaper of a distorted modulating code and a phase manipulator, the input of which is connected to the output of the amplitude modulator, and the output is connected to the input of the power amplifier, the second input of the registration unit is connected to the output of the phase detector.

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