RU2553065C1 - Panoramic receiver - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: panoramic receiver comprises five receiving antennae, input circuits, high frequency amplifiers, a mixer, an adjustment unit, a heterodyne, a scanning frequency generating device, an intermediate frequency amplifier, a detector, a video amplifier, first and second cathode-ray tubes, a delay line, a 90° phase changer, a multiplier, low-pass filters, narrow band-pass filters, phase meters and a recording unit.

EFFECT: high accuracy and unambiguity of finding the direction of a signal source in two planes.

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Description

The proposed receiver relates to the field of radio engineering and can be used to measure the carrier frequency and the type of modulation of signals received in a given frequency range, as well as direction finding of their radiation source in two planes.

Panoramic receivers are known (author's certificate of the USSR No. 1.272.266, 1.290.192, 1.354.124, 1.531.018, 1.661.661, 1.742.741, 1.832.215; RF patents No. 2.001.407, 2.010.244 , 2.010.245, 2.025.737, 2.030.750, 2.279.095, 2.366.079; US patents Nos. 4,443.801, 4.904.930; Vakin S.A., Shustov L.N. Fundamentals of radio countermeasures and electronic intelligence. M., Sov. Radio, 1968, p. 386, fig. 103 and others).

Of the known devices, the closest to the proposed one is "Panoramic receiver" (RF patent No. 2.279.096, G01R 23/00, 2005), which was chosen as a prototype.

The specified receiver provides a visual determination of the carrier frequency and the type of modulation of the received signal, but does not allow direction finding of their radiation source in two planes.

The technical task of the image is to expand the functionality of a panoramic receiver by accurately and unambiguously determining the direction of the radiation source of signals in two planes.

The problem is solved in that a panoramic receiver containing, in accordance with the closest analogue, a first receiving antenna, a first input circuit, a first high-frequency amplifier, a mixer, the second input of which is connected to the local oscillator output, an intermediate frequency amplifier, a detector, a video amplifier and vertically deflecting the plates of the first cathode ray tube, the horizontally deflecting plates of which are connected to the frequency sweep forming device, connected in series to the output of the intermediate frequency amplifier, a delay line, a first multiplier, the second input of which is connected to the output of the intermediate frequency amplifier, a first low-pass filter and vertically deflecting plates of the second cathode ray tube, 90 ° phase shifter connected to the output of the intermediate frequency amplifier, the second multiplier, the second the input of which is connected to the output of the delay line, and a second low-pass filter, the output of which is connected to horizontally deflecting plates of the second electron beam tubes, while the control inputs of the first input circuit, the first high-frequency amplifier, the local oscillator and the frequency sweep forming device are connected to the corresponding outputs of the tuning unit, according to the invention it is equipped with a recording unit and four direction finding channels, each of which consists of a receiving antenna, an input circuit, connected in series , high-frequency amplifier, multiplier, the second input of which is connected to the output of the intermediate frequency amplifier, narrow-band filter and phase meter, the second the path of which is connected to the output of the local oscillator, and the output is connected to the registration unit, the control inputs of each input circuit and each high-frequency amplifier connected to the corresponding outputs of the tuning unit, receiving antennas formed measuring bases, two on each plane, located in the form of a geometric right angle , at the top of which the first receiving antenna is placed, common to other receiving antennas located in the azimuthal and elevation planes, respectively, with the following relations:

where λ is the wavelength;

d ₁ d ₃ - measuring bases that form coarse, but unequivocal scales of reference azimuth α and elevation angle β, respectively;

d ₂ , d ₄ - measuring bases, forming accurate, but ambiguous scales of reference azimuth α and elevation angle β, respectively.

The block diagram of the panoramic receiver is shown in FIG. 1. A view of the possible waveforms on the screens of a CRT is shown in FIG. 2 and 3. A view of the complex envelope of the received signal is shown in FIG. 4. The relative position of the receiving antennas is shown in FIG. 5.

The panoramic receiver comprises in series a first receiving antenna 1, a first input circuit 2, a first high-frequency amplifier 3, a mixer 4, a second input of which is connected to the output of the local oscillator 6, an intermediate-frequency amplifier 8, a detector 9, a video amplifier 10, and vertically deflecting plates of the first electronic a beam tube (CRT) 11, the horizontal deflecting plates of which are connected to the output of the frequency sweep forming device 7, the input of which is connected to the corresponding output of the tuning unit 5. As the latter, an electric motor or sawtooth generator can be used. To the output of the intermediate frequency amplifier 8, a delay line 12, a first multiplier 14, the second input of which is connected to the output of the intermediate frequency amplifier 8, a first low-pass filter 16 and vertically deflecting plates of the second CRT 18 are connected in series 18. A phase shifter 13 is connected in series to the output of the intermediate frequency amplifier 8 90 °, the second multiplier 15, the second input of which is connected to the output of the delay line 12, and the second low-pass filter 17, the output of which is connected to the horizontally deflecting plates of CRT 1 8.

These blocks form the measuring channel of the panoramic receiver, which is equipped with four direction finding channels, each of which contains a receiving antenna 19 (20, 21, 22), an input circuit 23 (24, 25, 26), an amplifier 27 (28, 29, 30) ) high frequency multiplier 31 (32, 33, 34), the second input of which is connected to the output of an intermediate frequency amplifier 8, a narrow-band filter 35 (36, 37, 38) and a phase meter 39 (40, 41, 42), the second input of which is connected with the output of the local oscillator 6, and the output is connected to the block 43 registration. In this case, the control inputs of the input circuit 23 (24, 25, 26) and the high-frequency amplifier 27 (28, 29, 30) are connected to the corresponding outputs of the tuning unit 5. The receiving antennas 1, 19-22 are formed measuring bases, two on each plane, located in the form of a geometric right angle, at the top of which is placed the first receiving antenna 1, common to other receiving antennas 19-22, located in the azimuthal and elevation planes, respectively the fulfillment of the ratios:

where λ is the wavelength;

d ₁ , d ₃ - measuring bases that form coarse, but unequivocal scales of reference azimuth α and elevation angle β, respectively;

d ₂ , d ₄ - measuring base, forming accurate, but ambiguous scales of reference azimuth α and elevation angle β, respectively (Fig. 5).

Panoramic receiver operates as follows.

In the process of searching for signals of controlled electronic equipment (RES), the receiver is tuned in the specified frequency range Δf by the tuner 5, which, according to the linear law, consistently changes the settings of the input circuit 2, high-frequency amplifier 3, and local oscillator. At the same time, the tuning unit 5 controls the frequency scanning generation device 7 on the CRT screen 11.

The received signals, the carrier frequency and the type of modulation of which must be determined, can be represented as follows:

where V (t) is the envelope (amplitude varying in time) of the signal;

ω _s , φ _s , φ ₁ -φ ₄ , T _s - carrier frequency, initial phases and signal duration;

± Δω - carrier frequency instability due to various destabilizing factors, including the Doppler effect;

φ _n (t) is a nonlinear component that displays the type of manipulation.

We introduce the designation of the resulting phase of the signal

The carrier frequency ω _s does not affect the waveform, but only shifts its spectrum along the frequency axis. The waveform depends on the function V (t) and Ф (t), which form a complex envelope of the signal.

Therefore, to represent any signal, it is enough to know its carrier frequency and the two-component vector process - the complex envelope.

These signals from the output of the receiving antennas 1, 19-22 through the input circuit 2, 23-26 and high-frequency amplifiers 3, 27-30 are fed to the first inputs of the mixer 4, multipliers 31-34, respectively.

The voltage of the local oscillator 6 of a ramp frequency is supplied to the second input of the mixer 4

where V _Г , ω _Г , φ _Г , Т _П - amplitude, initial frequency, initial phase and repetition period of the local oscillator voltage;

- скорость перестройки частоты гетеродина в заданном диапазоне частот Δf. $$\gamma =\frac{\Delta f}{T_P}$$

- the frequency tuning frequency of the local oscillator in a given frequency range Δf.

At the output of the mixer 4, a voltage of combination frequencies is generated. Amplifier 8 is allocated voltage intermediate (differential) frequency

;Where $$V_{PR}\left(t\right)=\frac{\mathrm{one}}{2}V\left(t\right)\cdot V_g$$

;

ω _CR = ω _with -ω _G - intermediate (difference) frequency;

ω _CR = φ _s -φ _G ,

which, after detection in the detector 9 and additional amplification in the video amplifier 10, is applied to the vertically deflecting plates of the first CRT 11, as a result of which a pulse (frequency mark) is generated on the screen, the position of which determines the carrier frequency ω _with ± Δω of the received signal on the frequency scan (Fig. 2). In this case, the frequency sweep of the CRT 11 is calibrated in frequency units, which allows the operator to visually evaluate the carrier frequency of the received signal.

The voltage U _CR (t) from the output of the intermediate frequency amplifier 8 simultaneously enters the inputs of the delay line 12, the phase shifter 13 by 90 °, and the multiplier 14, 31-34 of the measuring and direction finding channels. At the outputs of the delay line 12 and the phase shifter 13 by 90 °, the following voltages are formed:

where τ is the delay time of the delay line 12, which are supplied to the inputs of the multipliers 14 and 15. In this case, the delay time τ is advisable to choose so that the inequality

where Δf _c is the frequency band occupied by the received signal.

The following voltages are formed at the outputs of the multipliers:

;Where $$V_{PR\mathrm{one}}\left(t\right)=\frac{\mathrm{one}}{2}V\left(t\right)\cdot V_{PR}\left(t-\tau \right)$$

;

ω _b = 2πγτ is the beat frequency;

φ _n1 (t) = φ _n (t-τ) -φ _n (t);

φ _in = ω _pr τ-πγτ ² ;

φ ₂ (t) = φ _n (t) -πγt ² + φ _pr.

Low-pass filters 16 and 17 from the resulting voltages U _Σ1 (t) and U _Σ2 (t) distinguish low-frequency beating voltages:

which are fed to the vertically deflecting and horizontally deflecting plates of the second CRT 18.

The indicated voltages contain all exhaustive information both on the value of the envelope V _pr1 (t) and on the phase difference

the accepted oscillations at two points in time that are separated by τ. This voltage on the plane corresponds to a point with coordinates U _н1 (t) and U _н2 (t) (Fig. 4). It is obvious that with a change in the envelope U _pr1 (t), the point shifts radially from the origin, and a change in the phase difference Δφ (t) leads to a rotation of this point in a circle around the center of coordinates. In connection with the above, different types of modulation in the plane [U _н1 (t), U _н2 (t)] will correspond to different images. In FIG. Figure 3 shows the waveforms for various classes that are formed on the screen of a CRT 18. Based on these waveforms, the operator can visually assess the type of modulation of the received signal.

The output of the multipliers 31-34 are formed voltage:

Where

The following inequalities are established between the measuring bases:

where λ is the wavelength;

d ₁ , d ₃ - measuring bases that form coarse, but unequivocal scales of reference azimuth α and elevation angle β, respectively;

d ₂ , d ₄ - measuring bases, forming accurate, but ambiguous scales of reference azimuth α and elevation angle β, respectively.

Thus, the proposed panoramic receiver in comparison with the prototype and other technical solutions for a similar purpose provides not only a measurement of the carrier frequency and the type of modulation of the received signal, but also provides accurate and unambiguous direction finding of its radiation source in two planes. In this case, the receiving antennas form two measuring bases in each plane, placed in the form of a geometric right angle, at the apex of which the first receiving antenna of the measuring channel is placed, common to other receiving antennas located in the azimuthal and elevation planes, respectively. Moreover, inequalities are established between the formed measuring bases:

The proposed panoramic receiver is invariant to the instability of the carrier frequency ± Δω and the type of modulation of the received signals, which allows to increase the accuracy of direction finding of radiation sources of signals with various types of modulation.

In addition, direction finding of radiation sources of signals is carried out at a frequency of ω _g local oscillator.

Thus, the functionality of the receiver is expanded.

Claims (1)

A panoramic receiver comprising a first receiving antenna in series, a first input circuit, a first high-frequency amplifier, a mixer, a second input of which is connected to the local oscillator output, an intermediate-frequency amplifier, a detector, a video amplifier, and vertically deflecting plates of the first cathode ray tube (CRT), horizontally the deflecting plates of which are connected to the output of the frequency sweep shaping device, the delay line is connected in series to the output of the intermediate frequency amplifier, the first a multiplier, the second input of which is connected to the output of the intermediate frequency amplifier, a first low-pass filter and vertically deflecting plates of the second CRT connected in series to the output of the intermediate frequency amplifier by a 90 ° phase shifter, a second multiplier, the second input of which is connected to the output of the delay line, and a second filter low frequencies, the output of which is connected to the horizontally deflecting plates of the second CRT, while the control inputs of the first input circuit, the first high-frequency amplifier, local oscillator and device The frequency sweep forming properties are connected to the corresponding outputs of the tuning unit, characterized in that it is equipped with a registration unit and four direction finding channels, each of which consists of a series input receiver antenna, a high frequency amplifier, a multiplier, the second input of which is connected to the output of the intermediate amplifier frequency, narrow-band filter and phase meter, the second input of which is connected to the output of the local oscillator, and the output is connected to the registration unit, and the control input Each input circuit and each high-frequency amplifier are connected to the corresponding outputs of the tuning block, measuring bases are formed by receiving antennas, two on each plane, located in the form of a geometric right angle, at the top of which there is a first receiving antenna common to other receiving antennas located in the azimuthal and elevation planes, respectively, with the fulfillment of the ratios:

where λ is the wavelength;
d ₁ , d ₃ - measuring bases that form coarse, but unequivocal scales of reference azimuth α and elevation angle β, respectively;
d ₂ , d ₄ - measuring bases, forming accurate, but ambiguous scales of reference azimuth α and elevation angle β, respectively.

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