RU2231926C1 - Monitoring device for pseudorandom operating frequency tuned radio stations - Google Patents

Abstract

FIELD: radio engineering.

SUBSTANCE: device designed to detect pseudorandom operating frequency tuned radio stations put on the air, to take their bearings, and to determine their frequency spectrum has receiving antennas, directivity pattern control unit, memory unit, frequency meter, four channels, four amplitude detectors, heterodyne, sawtooth voltage generator, stop pulse shaper, threshold unit, division circuit, switchboard, display, four narrow-band filters, five phase inverters, eight adders, four band filters, two 90 deg. phase shifters, two multipliers, and two switches. Device incorporates provision for eliminating ambiguity in determining frequency spectrum used.

EFFECT: enhanced selectivity and noise immunity of panoramic direction-finding receiver.

1 cl, 5 dwg

Description

The proposed device relates to the field of radio engineering and can be used to detect the broadcasting of radio stations with pseudo-random tuning of the operating frequency (PFRCH), their direction finding and determining the grid of used frequencies.

Currently, a large number of imported radio stations capable of operating in the mode of changing operating frequencies are available for sale. For example, the FT-2500 M radio station from YAESU can scan at 30 preset frequencies in the range 130-175 MHz. In negotiations, one word can be transmitted on one frequency, and the next on another. With an unknown ensemble of scanning frequencies, monitoring the operation of such radio stations is significantly complicated even when using a panoramic receiver with visual indication.

Indeed, it is necessary to establish the ownership of a short-term signal of a given radio station and evaluate its frequency, which is difficult in busy frequency ranges with weak useful signals and a large number of masking signals.

To select signals in the direction of arrival, panoramic receivers are equipped with direction-finding antennas. Known devices that provide direction finding either to the maximum amplitude of the signal, or to a minimum (Belavin OV Fundamentals of radio navigation. Publishing house 2 nd - Moscow: Sov. Radio, 1977, p. 98-110).

A significant reduction in the number of masking signals can be achieved with direction finding to the maximum by narrowing the antenna pattern. However, obtaining narrow radiation patterns in the ranges of relatively low frequencies is difficult. With direction finding to a minimum (with a cardioid radiation pattern), a significant reduction in the number of masking signals cannot be achieved.

Also known are devices for monitoring the operation of radio stations with pseudo-random tuning of the operating frequency (ed. Certificate of the USSR No. 403.084, 1.742.741, 1.760.471 RF patent No. 2.161.863, US patent No. 5.379.046; patent WO No. 96/9877; "Foreign Radio Electronics", Moscow: Sov. Radio, 1979, No. 3, p. 42-51, Fig. 5 and others).

Of the known devices, the closest to the proposed device is a "Device for monitoring the operation of radio stations with pseudo-random tuning of the operating frequency" (RF patent No. 2.161.863, N 04 V 7/08, 1998), which is selected as a prototype.

The specified device provides for the detection of weak short-term signals in the loaded frequency ranges and the assessment of their frequency against the background of a large number of powerful masking interference.

The essence of the device is to eliminate masking signals coming from other directions, to facilitate the detection of weak short-term signals with frequency hopping, measuring and recording the values of their frequencies.

However, in the known device, which is a panoramic direction finding receiver, the same value of the intermediate frequency ω _pr can be obtained by receiving signals at two frequencies ω _o and ω ₃ , i.e.

ω _pr = ω _about -ω _G and ω _pr = ω _G -ω _s .

Therefore, if the tuning frequency ω _{o is} taken as the main receiving channel, then along with it there will be a mirror receiving channel, the frequency ω ₃ , which differs from the frequency ω _o by 2ω _pr and is located symmetrically (mirror) with respect to the local oscillator frequency ω _G (Fig. .2). Conversion on the mirror channel of the reception occurs with the same conversion coefficient K _ol as on the main channel. Therefore, it most significantly affects the selectivity and noise immunity of the panoramic receiver-direction finder.

In addition to the mirror, there are other additional (combinational) reception channels, in general, any Raman reception channel has only the condition

ω _pr = | ± mω _ki ± nω _G |,

where ω _ki is the frequency of the i-th Raman reception channel;

m, n, i are positive integers, including n = 0.

The most harmful combinational reception channels are the channels formed during the interaction of the first harmonic of the signal frequency with the harmonics of the frequency of the local oscillator of the small order (second, third, etc.), since the sensitivity of the panoramic direction-finder through these channels is close to the sensitivity of the main channel. So, for two combinational channels with m = 1 and n = 2 there correspond frequencies:]

ω _к1 = 2ω _Г -ω _пр and ω _к2 = 2ω _Г + ω _пр .

If the carrier frequency of the interference ω _n is close to or equal to the intermediate frequency ω _pr (ω _n = ω _pr ), then a direct channel is formed. For this interference, the frequency converter plays the role of a simple transmission link.

If two large-amplitude signals at the frequency ω ₁ and ω ₂ (Fig. 3) are simultaneously input to the panoramic receiver-direction-finding detector, then they form a series of intermodulation interference on any nonlinear elements of the radio paths, the frequencies of which are determined by the formula:

mω ₁ ± nω ₂ = ω _mn .

The sum (difference) of the coefficients m and n is called the order, i.e. the intermodulation frequency ω _mn is called a frequency of the order of m ± n.

If the panoramic receiver-direction finder is tuned to one of these frequencies, then it will “listen” to the interference with “two-voice” modulation. This can be illustrated in figure 3. On it, the frequencies ω ₁ and ω _{2 of} strong out-of-band signals are conventionally taken equal to 27.1 and 27.2 MHz, respectively.

As can be seen from figure 3, two powerful signals generate a palisade of intermodulation frequencies, the strongest of which are of the order of 2 + 1 = 3. With an increase in the order of magnitude, the noise amplitudes quickly decrease. The more linear the receiving radio paths are, the smaller the amplitudes of the intermodulation noise and the faster they decrease with increasing order. The linearity of the receiving radio paths is also characterized by the magnitude of the dynamic range, i.e. a range of signal amplitudes from a minimum level equal to the intrinsic noise level of a panoramic receiver-direction finder to a maximum signal level at which non-linearity begins to appear. Since two signals are involved in the formation of intermodulation interference, the selectivity of the panoramic direction finder to these interference is called "two-signal selectivity."

If the interference frequency falls into the passband of the panoramic direction finder, it is received as a useful signal, i.e. existing filters are not able to eliminate it.

The use of highly selective quartz filters at an intermediate frequency ω _pr , improving the selectivity on the adjacent channel, can help suppress interference from one powerful out-of-band signal, but help powerlessly suppress intermodulation interference.

The presence of false signals (interference) received via mirror, Raman and intermodulation channels leads to a decrease in the selectivity and noise immunity of the panoramic direction finder, as well as to the ambiguity in determining the grid of frequencies used.

An object of the invention is to increase the selectivity and noise immunity of the panoramic receiver-direction finder, as well as the elimination of the ambiguity in determining the grid of frequencies used.

The problem is solved in that a device for monitoring the operation of radio stations with pseudo-random tuning of the operating frequency, containing two receiving antennas, a radiation pattern control unit, to the input of which a second antenna is connected, two radio paths, a first amplitude detector in series, a division circuit, the second input of which is connected with the output of the second amplitude detector, a threshold block, a stop pulse shaper, a sawtooth voltage generator and a local oscillator, the output of which is connected to the first the inputs of the first and second radio paths, connected in series to the second output of the first radio path, a frequency meter, the second input of which is connected to the output of the stop pulse shaper, and a memory unit, the second input of which is connected to the output of the stop pulse shaper, connected in series to the output of the switch division circuit, the second, the third and fourth inputs of which are connected to the outputs of the stop pulse shaper, the first and second amplitude detectors, respectively, and the indicator, the second input of which is dinene with the output of a sawtooth voltage generator, equipped with four narrow-band filters, six phase inverters, eight adders, four bandpass filters, third and fourth radio paths, third and fourth amplitude detectors, two 90 ° phase shifters, two multipliers and two keys, and to the output of the first receiving antennas are connected in series to the first narrow-band filter, the first phase inverter, the first adder, the second input of which is connected to the output of the first receiving antenna, the first bandpass iltr, the second phase inverter, the second adder, the second input of which is connected to the output of the first adder, the second bandpass filter, the third phase inverter and the third adder, the second input of which is connected to the output of the second adder, and the output is connected to the second input of the first radio path, to the second output of the local oscillator connected the first phase shifter 90 °, the third radio path, the second input of which is connected to the output of the third adder, the second phase shifter 90 °, the fourth adder, the second input of which is connected to the output of the first an adiotract, the fourth multiplier, the second input of which is connected to the output of the third adder, the second narrow-band filter, the third amplitude detector and the first switch, the second input of which is connected to the output of the fourth adder, and the output is connected to the input of the first amplitude detector, and the output of the second receiving antenna are connected in series the third narrow-band filter, the fourth phase inverter, the fifth adder, the second input of which is connected to the output of the radiation pattern control unit, the third band-pass filter, the fifth phase ertor, the sixth adder, the second input of which is connected to the output of the fifth adder, the fourth bandpass filter, the sixth phase inverter and the seventh adder, the second input of which is connected to the output of the sixth adder, and the output is connected to the second input of the second radio path, to the output of the first phase shifter 90 ° in series connected the fourth radio path, the second input of which is connected to the output of the seventh adder, the third phase shifter 90 °, the eighth adder, the second input of which is connected to the output of the second radio path, the second multiplier, Ora input of which is connected to the output of the seventh adder, the fourth narrowband filter, a fourth amplitude detector and a second key, the second input of which is connected to the output of the eighth adder, and an output connected to the input of the second amplitude detector.

The structural diagram of the proposed device is presented in figure 1. A frequency diagram explaining the process of forming additional receiving channels is shown in FIG. Examples of intermodulation interference are shown in FIGS. 3 and 4. The radiation patterns of the receiving antennas are shown in FIG. 5.

The device includes a series-connected first receiving antenna 1, the first narrow-band filter 15.1, the first phase shifter 16.1, the first adder 17.1, the second input of which is connected to the output of the antenna 1, the first bandpass filter 18.1, the second phase inverter 16.2, the second adder 17.2, the second input of which is connected to the output the adder 17.1, the second bandpass filter 18.2, the third phase inverter 16.3, the third adder 17.3, the second input of which is connected to the adder 17.2, the first radio path 6.1, the second input of which is connected to the first output of the local oscillator 8, the fourth sum 17.4, the first multiplier 20.1, the second input of which is connected to the output of the adder 17.3, the second narrow-band filter 15.2, the third amplitude detector 7.3, the first key 21.1, the second input of which is connected to the output of the adder 17.4, the first amplitude detector 7.1, the division circuit 12, the second input of which connected to the output of the second amplitude detector 7.2, a threshold unit 11, a generator stop pulse generator 10 (sawtooth voltage, the output of which is connected to the input of the local oscillator 8, to the output of which the first phase shifter 19 is connected in series .1 90 °, the third radio path 6.3, the second input of which is connected to the output of the adder 17.3, and the second phase shifter 19.2 by 90 °, the output of which is connected to the second input of the adder 17.4. A third narrow-band filter 15.3, a fourth phase inverter 16.4, a fifth adder 17.5, a second input of which is connected to the output of an antenna 2, a third bandpass filter 18.3, a fifth phase inverter 16.5, a sixth adder 16.5, a sixth adder 17.6, and a second input are connected to the output of the receiving antenna 2 in series which is connected to the output of the adder 17.5, the fourth bandpass filter 18.4, the sixth phase inverter 16.6, the seventh adder 17.7, the second input of which is connected to the output of the adder 17.6, the second radio path 6.2, the second input of which is connected to the output the local oscillator house 8, the eighth adder 17.8, the second multiplier 20.2, the second input of which is connected to the output of the adder 17.7, the fourth narrow-band filter 15.4, the seventh amplitude detector 7.4, the second switch 21.2, the second input of which is connected to the output of the adder 17.8 and the second amplitude detector 7.2. The fourth radio path 6.4, the second input of which is connected to the output of the phase shifter 19.1 by 90 °, and the phase shifter 19.3 by 90 °, the output of which is connected to the second input of the adder 17.8, are connected in series to the output of the adder 17.7. To the output of the division circuit 12, a switch 13 is connected in series, the second, third and fourth inputs of which are connected to the outputs of the stop pulse generator 10, amplitude detectors 7.1 and 7.2, respectively, and an indicator 14, the second input of which is connected to the output of the sawtooth voltage generator 9.

The proposed device operates as follows.

The search for radio frequency signals with frequency hopping is carried out in a given frequency range Д _f using a generator 9, which according to a sawtooth law changes the frequency of the local oscillator 8. At the same time, the generator 9 forms a horizontal scan of the oscilloscope indicator 14, which is used as the frequency axis.

The tuning frequency ω _{H1 of} narrow-band filters 15.1 and 15.3 is chosen equal to the intermediate frequency ω _pr

ω _H1 = ω _ave .

The tuning frequency ω _{H2 of} narrow-band filters 15.2 and 15.4 is chosen equal to the initial frequency of the local oscillator ω _G.

ω _H2 = ω _G.

The tuning frequency ω _H3 and the passband Δω _{П1 of the} bandpass filters 18.1 and 18.3 are selected as follows:

Δω_П1=ω₂-ω₁,

Δω _P1 = ω ₂ -ω ₁ ,

where ω ₁ , ω ₂ are the frequencies of two possible powerful signals, the appearance of which in the frequency band Δω _P1 , located "to the left" of the passband Δω _{P of the} panoramic direction finder, will lead to the formation of intermodulation interference.

The tuning frequency ω _H4 and the passband Δω _H4 and the passband Δω _{H2 of the} bandpass filters 18.2 and 18.4 are selected as follows:

Δω₂=ω₄-ω₃,

Δω ₂ = ω ₄ -ω ₃ ,

where ω ₃ , ω ₄ are the frequencies of two possible powerful signals, the appearance of which in the frequency band Δω _P2 , located "to the right" of the passband Δω _{P of the} panoramic direction-finding receiver, will lead to the formation of intermodulation interference.

The first receiving antenna 1 has a circular radiation pattern, and the second receiving antenna 2 has a cardioid radiation pattern (Fig. 5).

Received signals from radios with frequency hopping:

U ₁ (t) = U ₁ · Cos (ω _o t + φ ₁ );

U ₂ (t) = U ₂ · Cos (ω _o t + φ ₂ ), O≤t≤T _o ,

where U ₁ , U ₂ , ω _o , φ ₁ , φ ₂ , T _o are the amplitudes, carrier frequency, initial phases and signal duration: with the output of receiving antennas 1 and 2 through adders 17.1-17.7, for which only one arm operates, and the radiation pattern control unit 3 are supplied to the first inputs of the radio paths 6.1-6.4, the second inputs of which are fed to the local oscillator voltage 8:

U _Г1 (t) = U _Г · Cos (ω _Г t + πγt ² + φ _Г );

U _Г2 (t) = U _Г · Cos (ω _Г t + πγt ² + φ _Г + 90 °), O≤t≤T _П

where U _G , ω _g , φ _G , T _P - amplitude, initial frequency, initial phase and period of tuning of the local oscillator:

- скорость перестройки частоты гетеродина (скорость "просмотра" заданного диапазона частот Д_f).

- rate of tuning the frequency of the local oscillator (the speed of "viewing" a given frequency range D _f ).

Each radio path 6.1 (6.2-6.4) is a series-connected mixer, the second input of which is connected to the output of the local oscillator 8, and an intermediate frequency amplifier. At the output of the mixers, voltages of combination frequencies are formed. Amplifiers of intermediate frequency are allocated voltage only intermediate (differential) frequency. Therefore, the following voltages are formed at the outputs of the radio paths 6.1, 6.2, 6.3 and 6.4:

;

;

;

;

;

;

, O≤t≤I_o,

, O≤t≤I _o ,

Where

To ₁ - the transmission coefficient of the radio path;

ω _CR = ω _about -ω _G - intermediate frequency;

, которые в полосе пропускания радиотрактов Δω_П (полоса пропускания панорамного приемника-пеленгатора) приобретают принудительную линейную частотную модуляцию (ЛЧМ).

which in the passband of the radio paths Δω _P (passband of the panoramic direction finder-receiver) acquire forced linear frequency modulation (LFM).

Voltages U _CR3 (t) and U _CR4 (t) from the outputs of the radio _paths 6.3 and 6.4, respectively, are supplied to the inputs of the phase shifters 19.2 and 19.3 by 90 °, at the outputs of which the voltages are formed:

;

;

, O≤t≤T_o.

, O≤t≤T _o .

и

,

и

поступают на два входа сумматоров 17.4 и 17.8, на выходах которых образуются суммарные напряжения:Stress

and

,

and

arrive at two inputs of adders 17.4 and 17.8, at the outputs of which total voltages are formed:

;

;

, O≤t≤T_o;

, O≤t≤T _o ;

;

.Where

;

.

These voltages are applied to the first inputs of the multipliers 20.1 and 20.2, respectively, the second inputs of which receive the received signals U ₁ (t) and U ₂ (t) from the outputs of the adders 17.3 and 17.7. The outputs of the multipliers 20.1 and 20.2 are formed voltage:

;

;

, O≤t≤T_o,

, O≤t≤T _o ,

;Where

;

;

;

K ₂ - transmission coefficient of the multipliers;

и

через открытые ключи 21.1 и 21.2 соответственно поступают на входы амплитудных детекторов 7.1 и 7.2.which are distinguished by narrow-band filters 15.2 and 15.4 respectively, are detected by amplitude detectors 7.3 and 7.4 and fed to the control inputs of keys 21.1 and 21.2, in the initial state they are always closed. In this case, the total voltage

and

through public keys 21.1 and 21.2, respectively, enter the inputs of amplitude detectors 7.1 and 7.2.

Therefore, at the outputs of the adders 17.4 and 17.8, the input signals from the corresponding frequency range are sequentially allocated in time. After amplitude detection in amplitude detectors 7.1 and 7.2, these signals are fed to vertically deflecting plates of the cathode ray tube (oscilloscope indicator) 14, to the horizontally deflecting plates of which a sweep voltage is supplied from the output of the sawtooth voltage generator 9. As a result, a spectral density picture in the corresponding frequency range is formed on the screen of the oscilloscope indicator 14. Due to the fact that the same LFM signal from the outputs of the generator 8 is supplied to the reference inputs of the radio paths 6.1-6.4, the same input signal is observed at the outputs of the adders 17.4 and 17.8 at any time. The amplitude of the signal at the output of the adder 17.4 does not depend on the direction of arrival of the input signal due to the type of radiation pattern of the first receiving antenna 1 (Fig. 5). The second antenna 2 has a cardioid radiation pattern, the rotation of which is carried out by the control unit 3. The envelopes of the spectra of the input signals from the outputs of the amplitude detectors 7.1 and 7.2 are fed to the inputs of the division circuit 12 and switch 13. The switch 13 is used to connect one of the signals to the input of the indicator 14: the outputs of the adders 17.4, 17.8 and the output of the division circuit 12. To implement the selection of signals in the direction of arrival using the control unit 3, the cardioid radiation pattern of the antenna 2 is rotated to combine the zero dip with the direction of arrival of the signals (figure 5). The amplitude of the signals from this direction at the output of the adder 17.8 is close to zero, therefore, at the output of the division circuit 12, dividing the amplitude of the signal from the output of the adder 17.4 by the amplitude of the signal from the output of the adder 17.8, at this moment the voltage will be maximum.

It should be emphasized that the magnitude of the ratio does not depend on the field strength of the signals at the receiving site. The moment of maximizing the ratio is fixed by indicator 14. The threshold value is set so that the threshold block 11 is triggered only by signals coming from the zero direction.

When the threshold block 11 is activated, the driver 10 generates a pulse that stops the sawtooth voltage generator 9, starts the frequency counter 5, allows the signal to pass to the indicator 14 and write to the memory unit 4. During the duration of this pulse, the frequency counter 5 measures the frequency ω _{o of the} signal, which is recorded in the memory unit 4.

Thus, masking signals coming from other directions are established, and it becomes possible to detect weak short-term signals with frequency hopping, measure and record the values of their frequencies.

The operation of the device described above corresponds to the case of receiving useful signals with frequency hopping on the main channel at a frequency ω _o (figure 2).

If false signals (interference) are received on the mirror channel at a frequency of ω ₃

, O≤t≤T_з,

, O≤t≤T _s ,

,

,

then the following voltages are distinguished by radio paths 6.1-6.4:

;

;

, O≤t≤T_з,

, O≤t≤T _s ,

;Where

;

;

;

ω _CR = ω _G -ω ₃ - intermediate frequency;

;

.

;

.

и

с выходов радиотрактов 6.3 и 6.4 соответственно поступают на входы фазовращателей 19.2 и 19.3 на 90°, на выходах которых образуются напряжения:Stress

and

from the outputs of the radio paths 6.3 and 6.4, respectively, enter the inputs of the phase shifters 19.2 and 19.3 by 90 °, at the outputs of which voltages are generated:

;

;

, O≤t≤T_з.

, O≤t≤T _s .

и

,

и

, поступающие на два входа сумматоров 17.4 и 17.8, на их выходах компенсируются.Stress

and

,

and

entering the two inputs of the adders 17.4 and 17.8, at their outputs are compensated.

Consequently, false signals (interference) received through the mirror channel at a frequency of ω ₃ are suppressed using two external “rings”, each of which consists of radio paths 6.1 and 6.3 (6.2 and 6.4), a local oscillator 8, phase shifters 19.1 and 19.2 (19.3 ), adder 17.4 (17.8) and implements a phase-compensation method.

.For a similar reason, false signals (interference) received on the first combinational channel at a frequency are also suppressed.

.

(фиг.2)If false signals (interference) are received on the second combination channel at a frequency

(figure 2)

;

;

, O≤t≤

,

, O≤t≤

,

then the following voltages are distinguished by radio paths 6.1-6.4:

;

;

;

;

;

;

, O≤t≤

, O≤t≤

;Where

;

;

;

- промежуточная частота;

- intermediate frequency;

;

.

;

.

и

с выходов радиотрактов 6.3 и 6.4 соответственно поступают на входы фазовращателей 19.2 и 19.3 на 90°, на выходах которых образуются напряжения:Stress

and

from the outputs of the radio paths 6.3 and 6.4, respectively, enter the inputs of the phase shifters 19.2 and 19.3 by 90 °, at the outputs of which voltages are generated:

;

;

, O≤t≤

.

, O≤t≤

.

и

,

и

поступают на два входа сумматоров 17.4 и 17.8, на выходах которых образуются суммарные напряжения:Stress

and

,

and

arrive at two inputs of adders 17.4 and 17.8, at the outputs of which total voltages are formed:

;

;

, O≤t≤

,

, O≤t≤

,

;

.Where

;

.

и

с выходов сумматоров 17.3 и 17.7. На выходах перемножителей 20.1 и 20.2 образуются напряжения:These voltages are applied to the first inputs of the multipliers 20.1 and 20.2, to the second inputs of which the received signals

and

from the outputs of the adders 17.3 and 17.7. The outputs of the multipliers 20.1 and 20.2 are formed voltage:

;

;

, O≤t≤

,

, O≤t≤

,

;Where

;

,

,

, подавляются. При этом используются два внутренних "ключа", каждое из которых состоит из перемножителей 20.1 (20.2), узкополосного фильтра 15.2 (15.4), амплитудного детектора 7.3 (7.4), ключа 21.1 (21.2) и реализует метод узкополосной фильтрации.which do not fall into the passband of narrow-band filters 15.2 and 15.4. The keys 21.1 and 21.2 do not come off and false signals (interference) received on the second combination channel at a frequency

are suppressed. In this case, two internal “keys” are used, each of which consists of multipliers 20.1 (20.2), a narrow-band filter 15.2 (15.4), an amplitude detector 7.3 (7.4), a key 21.1 (21.2) and implements the method of narrow-band filtering.

If false signals (interference) are received on the direct channel at an intermediate frequency ω _CR :

;

;

, O≤t≤T₁,

, O≤t≤T ₁ ,

then from the outputs of the receiving antennas 1 and 2, they arrive at the first inputs of the adders 17.1 and 17.5, are distinguished by narrow-band filters 15.1 and 15.3, tuned to the intermediate frequency ω _pr , and are phase inverted by 180 ° in phase inverters 16.1 and 16.4:

;

;

, O≤t≤T₁.

, O≤t≤T ₁ .

и

, и

и

, поступающие на два входа сумматоров 17.1 и 17.5, на их выходах компенсируются.Stress

and

, and

and

entering the two inputs of the adders 17.1 and 17.5, at their outputs are compensated.

Consequently, false signals (interference) received through the direct channel at an intermediate frequency are suppressed by two filter plugs, each of which consists of a narrow-band filter 15.1 (15.3), a phase inverter 16.1 (16.4), an adder 17.1 (17.5) and implements a phase-compensation method .

"слева" от полосы пропускания Δω_П, панорамного приемника-пеленгатора, способные образовать интермодуляционные помехи, то они выделяются полосовыми фильтрами 18.1 и 18.3, инвертируются по фазе на 180° фазоинверторами 16.2 и 16.5 и компенсируются в сумматорах 17.2 и 17.6 (фиг.3).If two powerful false signals (interference) at frequencies ω ₁ and ω ₂ or several powerful signals (interference) appear simultaneously in the frequency band

"to the left" of the bandwidth Δω _P , panoramic receiver-direction finder capable of intermodulation interference, they are allocated by bandpass filters 18.1 and 18.3, phase inverted by 180 ° by phase inverters 16.2 and 16.5 and compensated in adders 17.2 and 17.6 (Fig. 3) .

и образующие интермодуляционные помехи подаются двумя фильтрами-пробками, каждый из которых состоит из полосового фильтра 18.1 (18.3), фазоинвертора 16.2 (16.5), сумматора 17.2 (17.6) и реализует фазокомпенсационный метод.Therefore, false signals (interference) received in the frequency band

and generating intermodulation noise is supplied by two filter plugs, each of which consists of a bandpass filter 18.1 (18.3), a phase inverter 16.2 (16.5), an adder 17.2 (17.6) and implements a phase compensation method.

"справа" от полосы пропускания Δω_П панорамного приемника-пеленгатора, способные образовать интермодуляционные помехи, то они выделяются полосовыми фильтрами 18.2 и 18.4, инвертируются по фазе на 180° фазоинверторами 16.3 и 16.6 и компенсируются в сумматорах 17.3 и 17.7 (фиг.4).If two powerful false signals (interference) at frequencies ω ₃ and ω ₄ or several powerful signals (interference) appear simultaneously in the frequency band

"to the right" of the passband Δω _{P of the} panoramic direction-finder receiver, capable of generating intermodulation interference, they are distinguished by bandpass filters 18.2 and 18.4, phase inverted by 180 ° by phase inverters 16.3 and 16.6 and compensated in adders 17.3 and 17.7 (Fig. 4).

и образующие интермодуляционные помехи, подавляются двумя фильтрами-пробками, каждый из которых состоит из полосового фильтра 18.2 (18.4), фазоинвертора 16.3 (16.6), сумматора 17.3 (17.7) и реализует фазокомпенсационный метод.Therefore, false signals (interference) received in the frequency band

and generating intermodulation interference, are suppressed by two filter plugs, each of which consists of a bandpass filter 18.2 (18.4), a phase inverter 16.3 (16.6), an adder 17.3 (17.7) and implements a phase compensation method.

The control unit 3 of the rotating cardioid radiation pattern can be performed according to Fig. 9.10 on p. 131 in the book of Fradkin A.Z. Antenna feeder devices. M .: Communication, 1977.

The circuit 12 for dividing two analog signals can be performed by including a multiplier in the feedback circuit of the amplifier (Alekseenko V.I. et al. Use of precision analog microcircuits. 2nd edition. M: Radio and communications, p.113, 114).

Thus, the proposed device in comparison with the prototype and other technical solutions for a similar purpose provides increased selectivity and noise immunity of the panoramic receiver-direction finder, and also eliminates the ambiguity in determining the grid of frequencies used. This is achieved by suppressing false signals (interference) received via mirror, Raman and intermodulation channels, using the phase-compensation method and the narrow-band filtering method.

Claims (1)

A device for monitoring the operation of radio stations with pseudo-random tuning of the operating frequency, containing two receiving antennas, a radiation pattern control unit, to the input of which a second antenna is connected, two radio paths, a first amplitude detector, a division circuit, the second input of which is connected to the output of the second amplitude detector, threshold block, stop pulse generator, sawtooth generator and local oscillator, the output of which is connected to the first inputs of the first and second radiotra ktov, connected in series to the second output of the first radio path, a frequency meter, the second input of which is connected to the output of the stop pulse shaper, a memory unit, the second input of which is connected to the output of the stop pulse shaper, the switch is connected in series to the output of the dividing circuit, the second, third and fourth inputs of which are connected with the outputs of the stop pulse generator, the first and second amplitude detectors, respectively, and the indicator, the second input of which is connected to the generator output o voltage, characterized in that it is equipped with four narrow-band filters, six phase inverters, eight adders, four bandpass filters, third and fourth radio paths, third and fourth amplitude detectors, three phase shifters 90 °, two multipliers and two keys, and to the output of the first the receiving antenna is connected in series to the first narrow-band filter, the first phase inverter, the first adder, the second input of which is connected to the output of the first receiving antenna, the first band-pass filter, the second azoinverter, a second adder, the second input of which is connected to the output of the first adder, a second bandpass filter, a third phase inverter and a third adder, the second input of which is connected to the output of the second adder, and the output is connected to the second input of the first radio path, the first phase shifter is connected in series to the second output of the local oscillator 90 °, the third radio path, the second input of which is connected to the output of the third adder, the second phase shifter 90 °, the fourth adder, the second input of which is connected to the output of the first radio path, a second multiplier, the second input of which is connected to the output of the third adder, the second narrow-band filter, the third amplitude detector and the first key, the second input of which is connected to the output of the fourth adder, and the output is connected to the input of the first amplitude detector, the third narrow-band is connected in series to the output of the second receiving antenna filter, fourth phase inverter, fifth adder, the second input of which is connected to the output of the radiation pattern control unit, third bandpass filter, fifth phase inverter, sixth sum the second input of which is connected to the output of the fifth adder, the fourth bandpass filter, the sixth phase inverter and the seventh adder, the second input of which is connected to the output of the sixth adder, and the output is connected to the second input of the second radio path, the fourth radio path is connected in series to the output of the first phase shifter 90 ° the second input of which is connected to the output of the seventh adder, the third phase shifter 90 °, the eighth adder, the second input of which is connected to the output of the second radio path, the second multiplier, the second input of which connected to the output of the seventh adder, the fourth narrowband filter, a fourth amplitude detector and a second key, the second input of which is connected to the output of the eighth adder, and an output connected to the input of the second amplitude detector.

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