RU2010245C1 - Panoramic receiver - Google Patents

Abstract

FIELD: measurement technology. SUBSTANCE: panoramic receiver has five aerials 1,11,23,24,25, sweep generator 2, two local oscillators 3, 29, six mixers 4,20,26,27,28,29, five intermediate frequency amplifiers 5,30,31,32,33, detector 6, scale-of-eight multiplier 7, two spectrum width meters 8,9 comparator 10, threshold unit 11, key 12, delay line 13, five multipliers 14,35,36,37. n band-pass filters 15.1. . . 15. n, n amplitude detectors 26.1. . . 16. n, n video amplifiers 17.1. . . 17. n, n cathode-ray tubes 18.1. . . 18. n, amplifier 21 of second intermediate frequency four narrow-band filters 38,39,40,41, four phase detectors 42,43,44,45, four indicator 46,47,48, 49. EFFECT: expanded operational capabilities and improved operational characteristics. 2 dwg

Description

 The invention relates to radio engineering and can be used to search and detect phase-shift (PSK) signals, visually evaluate their carrier frequency and determine the radiation source of these signals in two planes.

 Closest to the proposed is a panoramic receiver, which provides search and detection of PSK signals, as well as a visual assessment of their carrier frequency, but does not allow direction finding of the radiation source of PSK signals.

 The aim of the invention is to expand the functionality of the receiver by accurate and unambiguous direction finding of the radiation source of FMN signals in two planes.

 The goal is achieved by the fact that a second local oscillator, a second mixer, an amplifier of the second intermediate frequency, and four measuring reception channels, each of which consists of a series-connected receiving antenna, a mixer, the second input of which is connected to the output of the first local oscillator, an amplifier of the first intermediate frequency, are introduced into the receiver , a multiplier, the second input of which is connected to the output of the amplifier of the second intermediate frequency, a narrow-band filter, a phase detector, the second input of which is connected to the output of the second hetero a, and an indicator, wherein the exit key second mixer connected in series, a second input coupled to an output of the second oscillator and the second intermediate frequency amplifier.

 The block diagram of the proposed receiver is presented in FIG. 1; the relative position of the antennas and the principle of direction finding of the radiation source of the PSK signals in two planes are shown in FIG. 2.

The panoramic receiver includes a first antenna 1, a sweep generator 2, a first local oscillator 3, a first mixer 4, a first amplifier 5 of a first intermediate frequency, a detector 6, a frequency multiplier 7 by eight, the first 8 and second 9 meters of the spectrum width, a comparison unit 10, a threshold block 11, key 12, delay line 13, first multiplier 14, band pass filters 15 ₁ . . . 15 _n , amplitude detectors 16 ₁ . . . 16 _n , video amplifiers 17 ₁ . . . 17 _n , cathode ray tubes (CRT) 18 ₁ . . . 18 _n , second local oscillator 19, second mixer 20, second intermediate frequency amplifier 21, second 22, third 23, fourth 24 and fifth 25 antennas, third 26, fourth 27, fifth 28 and sixth 29 mixers, second 30, third 31, fourth 32 and fifth 33 amplifiers of the first intermediate frequency, second 34, third 35, fourth 36 and fifth 37 multipliers, first 38, second 39, third 40 and fourth 41 narrow-band filters, first 42, second 43, third 44 and fourth 45 phase detectors, first 46, second 47, third 48 and fourth 49 indicators. A local oscillator 3, a mixer 4, the second input of which is connected to the output of the antenna 1, an amplifier 5 of the first intermediate frequency, a frequency multiplier 7, a measuring instrument 9 of the spectrum, a comparison unit 10, the second input of which through the meter 8 of the width the spectrum is connected to the output of the amplifier 5 of the first intermediate frequency, the threshold block 11, the key 12, the second input of which is connected to the output of the amplifier 5 of the first intermediate frequency, the delay line 13, the multiplier 14, the second input of which is connected to Odom key 12 and the n processing channels, each of which consists of series-connected band-pass filter 15i, amplitude detector 16i, 17i video amplifier and the CRT vertical electrode 18i, the horizontal electrode which is connected to the second output of the sweep generator 2. To the output of the key 12, a mixer 20 is connected in series, the second input of which is connected to the output of the local oscillator 19, and an amplifier 21 of the second intermediate frequency. Each of the measuring reception channels contains a series-connected antenna 22 (23-25), a mixer 26 (27-29), the second input of which is connected to the output of the local oscillator 3, an amplifier 30 (31-33) of the first intermediate frequency, a multiplier 34 (35-37 ), a narrow-band filter 38 (39-41), a phase detector 42 (43-45), the second input of which is connected to the output of the local oscillator 19 and indicator 46 (47-49).

 Direction finding of the radiation source of the QPSK signals by the proposed receiver is carried out by the phase method, which is characterized by a contradiction between the requirements for ensuring the accuracy of measurements and the uniqueness of the angle reading.

sinα; =Δφ₂= 2

sinβ , где d₁ - измерительная база (расстояние между антеннами);
λ - длина волны;
α - угол прихода радиоволн в азимутальной плоскости;
β - угол прихода радиоволн в угломерной плоскости, приемник тем чувствительнее к изменению углов α и β, чем больше относительный размер базы d₁/λ. Однако с ростом d₁/λ уменьшаются значения угловых координат α и β, при которых разности фаз Δφ₁ и Δφ₂превосходят значение 2 π, т. е. наступает неоднозначность отсчета.Valid according to the formulas
Δφ ₁ = 2

sinα; = Δφ ₂ = 2

sinβ, where d ₁ is the measuring base (distance between antennas);
λ is the wavelength;
α is the angle of arrival of radio waves in the azimuthal plane;
β is the angle of arrival of radio waves in the goniometric plane, the receiver is the more sensitive to changes in the angles α and β, the larger the relative size of the base d ₁ / λ. However, with increasing d ₁ / λ, the values of the angular coordinates α and β decrease, at which the phase differences Δφ ₁ and Δφ ₂ exceed the value 2 π, i.e., the reading is ambiguous.

<

<

.The ambiguity of direction finding by the phase method can be eliminated by using two measuring bases in each plane, between the relative sizes of which the following relationship is established:

<

<

.

Moreover, a smaller base d ₁ forms a rough but unambiguous reference scale, and a large base d ₂ forms an accurate but ambiguous reference scale. Moreover, the measuring base form a right angle, at the top of which is the first antenna of the reference reception channel.

 Panoramic receiver operates as follows.

Viewing a given frequency range Df is carried out using a sweep generator 2, which periodically with a period T _p according to a sawtooth law tunes the frequency of the local oscillator 3. At the same time, sweep generator 2 forms a horizontal scan of a CRT 18 ₁ . . . 18 _n , which is used as the frequency axis, and its length corresponds to the frequency span Df. The key 12 in the initial state is always closed.

- скорость изменения частоты гетеродина (скорость изменения первой гармоники частоты гетеродина).Received QPSK signals
U ₁ (t) = U _c ˙ Cos [2 π f _c t + φ _к (t) + φ ₁ ];
U ₂ (t) = U _c ˙ Cos [2 π f _c t + φ _к (t) + φ ₂ ];
U ₃ (t) = U _c ˙ Cos [2 π f _c t + φ _к (t) + φ ₃ ];
U ₄ (t) = U _c ˙ Cos [2 π f _c t + φ _к (t) + φ ₄ ];
U ₅ (t) = U _c ˙ Cos [2 π f _c t + φ _к (t) + φ ₅ ], where U _с , f _c , Т _с , φ ₁ , φ ₂ , φ ₃ , φ ₄ , φ ₅ - amplitude, carrier frequency, duration and initial phases of the signals;
φ _a (t) - manipulated component phase mapping law phase shift keying in accordance with a modulation code, wherein φ _a (t) = const for K τ _and <t <(K + 1) x τ _u and may vary abruptly at t = K τ _and , i.e., at the boundaries between the elementary premises (K = 0,1,2..., N-1);
τ _and , N is the duration and number of chips that make up the signals of duration T _s (T _s = N τ _and ), from the outputs of the antennas 1.22-25 go to the first inputs of the mixers 4, 26-29, to the second inputs of which the voltage of the local oscillator 3 linearly changing frequency
U _g1 (t) = U _g1 ˙ Cos (2 π f _g1 t +
+ πγ ₁ t ² + φ _g1 ), 0 ≅ t ≅ T _p , where U _g1 , f _g1 , T _p , φ _g1 - amplitude, initial phase, repetition period and initial phase of the local oscillator voltage 3;
γ ₁ =

- rate of change of the local oscillator frequency (rate of change of the first harmonic of the local oscillator frequency).

· К₁· U_c · U_г1; 0 ≅ t ≅T_с,
К₁ - коэффициент передачи смесителей;
f_пр1 = f_c - f_г1 - первая промежуточная частота;
φ_пр1 = φ₁ - φ_г1;
φ_пр2 = φ₂ - φ_г1;
φ_пр3 = φ₃ - φ_г1;
φ_пр4 = φ₄ - φ_г1;
φ_пр5 = φ₅ - φ_г1, которые представляют собой сигналы с комбинированной линейной частотной модуляцией и фазовой манипуляцией (ЛЧМ-ФМн).At the output of the mixers 4, 26-29, voltages of combination frequencies are generated. Amplifiers 5, 30-33 distinguish the voltage of the first intermediate (differential) frequency
U _pr1 (t) = U _pr1 ˙ Сos [2 π f _pr1 t +
+ φ _{to (} t) - πγ ₁ t ² + φ _pr1 ];
U _pr2 (t) = U _pr1 ˙ Cos [2 π f _pr1 t +
+ φ _to (t) - πγ ₁ t ² + φ _pr2 ];
U _CR3 (t) = U _CR1 ˙ Cos [2 π f _CR1 t +
+ φ _to (t) - πγ ₁ t ² + φ _pr3 ];
U _CR4 (t) = U _CR1 ˙ Cos [2 π f _CR1 t +
+ φ _to (t) - πγ ₁ t ² + φ _pr4 ];
U _CR5 (t) = U _CR1 ˙ Cos [2 π f _CR1 t +
+ φ _к (t) - πγ ₁ t ² + φ _пр5 ], where U _пр1 =

· K ₁ · U _c · U _g1 ; 0 ≅ t ≅T _s ,
To ₁ - gear ratio of the mixers;
f _CR1 = f _c - f _g1 - the first intermediate frequency;
φ _pr1 = φ ₁ - φ _g1 ;
φ _CR2 = φ ₂ - φ _g1 ;
φ _CR3 = φ ₃ - φ _g1 ;
φ _pr4 = φ ₄ - φ _g1 ;
φ _pr5 = φ ₅ - φ _g1 , which are signals with combined linear frequency modulation and phase shift keying (LFM-PSK).

The voltage U _PR1 (t) from the output of the amplifier 5 of the first intermediate frequency is supplied to the input of the detector 6, consisting of a frequency multiplier 7 by eight, meters 8 and 9 of the spectrum width, comparison unit 10, threshold block 11 and key 12.

At the output of the frequency multiplier 7 by eight, a voltage is generated
U ₆ (t) = U _{CR 1} Cos (16 π f _{CR 1} t -
- 8 πγ ₁ t ² + 8φ _pr1 ), 0 ≅ t ≅ T _c .

Since 8 φ _к (t) = {0.8 π} when receiving a signal with a single phase shift keying [FMN-2, φ _к (t) = {0, π}], 8 φ _к (t) = {0, 4π, 8π, 12 π} when receiving a signal with double phase shift keying [FMN-4, φ _к (t) = {0, π / 2, π, 3 / 2π}], 8 φ _к (t) = {0, 2 π, 4π, 6 π, 8 π, 10 π, 12 π, 14π}] when receiving a signal with three-phase phase shift keying [FMN-8, φ _к (t) = {0, π / 4, π / 2, 3 / 4 π, π, 5/4 π, 3/2 π, 7/4 π}], then phase oscillation is already absent in the indicated oscillation.

The width of the spectrum Δ f _{1 of the} eighth harmonic is determined by the duration T _{s of the} signal (Δf ₁ = 1 / T _c ), while the width of the spectrum Δ f _{c of the} QPSK signal is determined by the duration τ _and its elementary premises (Δf _c = 1 / τ _и ), t i.e., the spectrum width Δ f _{1 of the} eighth harmonic of the signal is N times smaller than the spectrum width Δf _{c of the} input signal:
Δ f _c / Δ f ₁ = N.

 Therefore, when the frequency of the QPSK signal is multiplied by eight, its spectrum “folds” N times. This makes it possible to detect the QPSK signal even when its power at the receiver input is less than the noise power.

The spectral width Δ f _{c of the} input QPSK signal is measured using meter 8, and the spectral width Δ f _{1 of the} eighth harmonic of the signal is measured using meter 9. Voltages U ₄ and U ₁ proportional to Δf _c and Δ f _1, respectively, from the outputs of the meters 8 and 9 spectral widths are fed to two inputs of the comparison unit 10. Since U >>>> U ₁ , a positive voltage is generated at the output of the comparison unit 10, which exceeds the threshold level U _then in the threshold block 11. The threshold level U _then is chosen so that it does not exceed random interference. When the threshold level U _pores is exceeded, a constant voltage is generated in the threshold block 11, which is supplied to the control input of the key 12, opening it. In this case, the voltage U _pr1 (t) from the output of the amplifier 5 of the first intermediate frequency through the public key 12 is simultaneously supplied to the first input of the multiplier 14, to the input of the delay line 13, at the output of which a voltage is generated
U _CR6 (t) = U _CR1 (t - τ _h ) = U _CR1 ˙ Cos [2 πf _CR1 x
x (t - τ _s ) + φ _to (t - τ _s ) -πγ ₁ (t-τ _s ) ² + φ _pr1 ],
0 ≅ t ≅ T _c , where τ _s is the delay time of the delay line 13.

K₂·U

;
К₂ - коэффициент передачи перемножителя 14;
f_δ1= γ₁τ_з - частота биений;

(t) = φ_к(t-τ_з)-φ_к(t);

= 2πf

+πγ₁τ $\genfrac{}{}{0ex}{}{\text{2}}{\text{з}}$ .The output of the multiplier 14 produces a voltage
U _δ1 (t) = U _δ ˙cos (2πf _δ1 t + φ _к1 (t) + φ _δ1 ),
0 ≅ t ≅ T _s , where U _b =

K ₂ · U

;
To ₂ - the transfer coefficient of the multiplier 14;
f _δ1 = γ ₁ τ _s - beat frequency;

(t) = φ _k (t-τ _h ) -φ _k (t);

= 2πf

+ πγ ₁ τ $\genfrac{}{}{0ex}{}{\text{2}}{\text{s}}$ .

The frequency of the beat voltage U _δ1 (t) is f _δ1 = γ ₁ ˙τ _s = const. Therefore, with a fixed delay time τ _s , a multi-beat signal is generated at the output of multiplier 14, the frequency f _{δ1 of} which depends on the rate of change of the frequency γ _i (i = 1,2, ..., n) of the local oscillator 3. The rate of change of the frequency of the converted signal, coming to the input of the autocorrelator, depends on the harmonic number of the local oscillator frequency 3, interacting with the carrier frequency of the received PSK signal.

The tuning frequency of the bandpass filter 15 ₁ is chosen equal to
f _n1 = f _δ1 = γ ₁ зτ _s , the tuning frequency of the band-pass filter 15 ₂ is chosen equal
f _n2 = f _δ2 = γ ₂ ˙τ _s , and the tuning frequency of the band-pass filter 15 _n is chosen equal to
f _nn = f _δn = γ _n ˙τ _s , where γ _n = nγ ₁ is the rate of change of the nth harmonic of the local oscillator frequency 3.

The voltage U _δi (t) from the output of the bandpass filter 15 _{i is} supplied to the input of the amplitude detector 16 _i , where it is detected and, after amplification in the video amplifier 17 _{i, is} supplied to the vertical CRT electrode 18 _i , on the screen of which a pulse is generated (frequency mark) (i = 1,2,..., N). The position of the frequency mark on the horizontal scan of the CRT 18 _i uniquely determines the carrier frequency f _{c of the} received FMN signal.

 Consequently, the harmonic number of the local oscillator frequency 3, with which the carrier frequency of the received PSK signal interacts, is determined by the number of the band-pass filter of that channel on the CRT screen of which a frequency mark is observed.

The voltage U _pr1 (t) from the output of the amplifier 5 of the first intermediate frequency through the public key 12 is simultaneously supplied to the first input of the mixer 20, the second input of which is supplied from the output of the local oscillator 19
U _r2 (t) = U _r2 ˙cos (2πf _{r2 r2} t + φ), where U _r2, f _r2, φ _r2 - amplitude, frequency and initial phase of the local oscillator 19 voltage.

· K₁ · U_пр1·U_г2;
f_пр2= f_пр1-f_г2 - вторая промежуточная частота; φ_пр6= φ_пр1-φ_г2 .At the output of the mixer 20, voltages of combination frequencies are generated. The amplifier 21 is allocated the voltage of the second intermediate (differential) frequency
U _pr7 (t) = U _pr2 ˙ Cos [2 πf _pr2 t +
+ φ _k (t) - πγ ₁ t ² + φ _{CR 6} ], 0 ≅ t ≅ T _c , where U _{CR 7} =

· K ₁ · U · U _{pr1 r2;
np2} f = f _r2 -f _pr1 - second intermediate frequency; cp = φ _{pr6 pr1} -φ _r2.

· K₂ · U_пр1· U_пр2; 0 ≅ t ≅ T_c,

- фазовые сдвиги, определяющие направление на источник излучения в азимутальной плоскости;

- фазовые сдвиги, определяющие направление на источник излучения в угломестной плоскости, в которых фазовая манипуляция и линейная частотная модуляция уже отсутствуют. Гармонические напряжения U₇(t), U₈(t), U₉(t) и U₁₀(t) выделяются узкополосными фильтрами 38, 39, 40 и 41 и поступают на первые входы фазовых детекторов 42, 43, 44 и 45, на вторые входы которых подается напряжение U_г2(t) с выхода гетеродина 19. На выходах фазовых детекторов 42-45 образуются постоянные напряжения
U_н1 = U_н ˙ Cos Δφ₁;
U_н2 = U_н ˙ Cos Δφ₂;
U_н3 = U_н ˙ Cos Δφ₃;
U_н4 = U_н ˙ Cos Δφ₄, где U_н =

· К₃ · U₂ ·U_г2;
К₃ - коэффициент передачи фазовых детекторов;
Δφ₁ = 2

sin α;
Δφ₂ = 2

sinβ;
Δφ₃ = 2

sin α;
Δφ₄ = 2

sin β;
d₁, d₂, α - измерительные базы и угол прихода радиоволн в азимутальной плоскости;
d₁, d₂, β - измерительные базы и угол прихода радиоволн в угломестной плоскости.Voltages U _CR2 (t), U _CR3 (t), U _CR4 (t) and U _CR5 (t) from the outputs of amplifiers 30.. . 33 of the first intermediate frequency are supplied to the first inputs of the multipliers 34.. . 37, to the second inputs of which a voltage U _pr7 (t) is supplied from the output of the amplifier 21 of the second intermediate frequency. At the outputs of the multipliers 34.. . 37 harmonic stresses are formed
₇ U (t) = U ₂ ˙ cos (2 πf _{r2 r2} t + φ ₁ + Δφ);
₈ U (t) = U ₂ ˙ cos (2 πf _{r2 r2} t + φ + Δφ _2);
9 U (t) = U ₂ ˙ cos (2 πf _{r2 r2} t + φ + Δφ _3);
10 U (t) = U ₂ ˙ cos (2 πf _{r2 r2} t + φ + Δφ _4). where U ₂ =

· K ₂ · U _pr1 · U _pr2 ; 0 ≅ t ≅ T _c ,

- phase shifts that determine the direction to the radiation source in the azimuthal plane;

- phase shifts, which determine the direction to the radiation source in the elevation plane, in which phase shift keying and linear frequency modulation are already absent. Harmonic voltages U ₇ (t), U ₈ (t), U ₉ (t) and U ₁₀ (t) are allocated by narrow-band filters 38, 39, 40 and 41 and are fed to the first inputs of phase detectors 42, 43, 44 and 45, at the second inputs of which a voltage U _g2 (t) is supplied from the output of the local oscillator 19. At the outputs of the phase detectors 42-45, constant voltages are generated
U _n1 = U _n ˙ Cos Δφ ₁ ;
U _n2 = U _n ˙ Cos Δφ ₂ ;
U _n3 = U _n ˙ Cos Δφ ₃ ;
U _n4 = U _n ˙ Cos Δφ ₄ , where U _n =

· K ₃ · U ₂ · U _g2 ;
K ₃ - transfer coefficient of phase detectors;
Δφ ₁ = 2

sin α;
Δφ ₂ = 2

sinβ;
Δφ ₃ = 2

sin α;
Δφ ₄ = 2

sin β;
d ₁ , d ₂ , α — measuring bases and angle of arrival of radio waves in the azimuthal plane;
d ₁ , d ₂ , β — measuring bases and angle of arrival of radio waves in the elevation plane.

<

<

.In each plane between the relative dimensions of the measuring bases, the following relationship is established:

<

<

.

Moreover, a smaller base d ₁ forms a rough but unambiguous reference scale, and a large base d ₂ forms an accurate but ambiguous reference scale. The measuring bases form a right angle at the apex of which the antenna 1 of the reference receiving channel is installed, consisting of a series-connected antenna 1, mixer 4, amplifier 5 of the first intermediate frequency, detector 6, mixer 20, the second input of which is connected to the output of the local oscillator 19, and amplifier 21 second intermediate frequency. Voltages U _н1 , U _н2 , U _н3 and U _н4 are fixed by indicators 46.. . 49.

<

<

.Thus, the proposed receiver in comparison with the prototype provides accurate and unambiguous direction finding of the radiation source of FMN signals in two planes. This is achieved by using in each plane two measuring bases, between the relative sizes of which the following relationship is established:

<

<

.

Moreover, a smaller base d ₁ forms a rough but unambiguous reference scale, and a large base d ₂ forms an accurate but ambiguous reference scale. All measuring bases form a right angle at the apex of which the antenna 1 of the reference reception channel is installed, which is common for both planes, which reduces the number of antennas (instead of eight, five are used) and increase the sensitivity of the receiver. This is due to the fact that due to the multiplication of voltages U _CR2 (t), U _CR3 (t), U _CR4 (t) and U _CR5 (t) of the first intermediate frequency of the measuring channels with voltage U _CR7 (t) of the second intermediate frequency of the reference channel convolution of the spectrum of received QPSK signals is performed N times, which makes it possible to isolate harmonic oscillations U ₇ (t), U ₈ (t), U ₉ (t) and U ₁₀ (t) using narrow-band filters 38.. . 41, having filtered out a considerable part of noise and interference, i.e., to increase the sensitivity of the receiver during direction finding of the radiation source of complex FMN signals. Moreover, the direction finding of the radiation source of complex QPSK signals is carried out at a fixed stable frequency f _{g2 of the} second local oscillator 19, which eliminates the influence of instability of the carrier frequency f _{from the} received QPSK signals on the direction finding results. It should also be noted that the proposed receiver is invariant to the type of modulation of the received complex signals. Thus, the functionality of the panoramic receiver is expanded.

Claims (1)

 A PANORAMIC RECEIVER containing a first-round first-order antenna, a first mixer, a second input of which is connected to the first output of the clock generator, a first amplifier, and an alternating frequency converter, is an additional frequency the spectral width meter is connected to the output of the first amplifier of the first intermediate frequency, a threshold unit, a key, the second input of which is connected to the output of the first amplifier of the first intermediate frequency, a delay line, the first multiplier, the second input of which is connected to the output of the key and signal processing channels, each of which consists of a series-pass band-pass filter, an amplitude detector, a video amplifier and a horizontal electrode with a horizontal characterized in that a second heterodyne, a second mixer, an amplifier of the second intermediate frequency and four measuring channels, each of which consistently include values of the secondary antenna, the mixer, the second input of which is connected to the output of the first heterodyne, the amplifier of the first intermediate frequency, the multiplier, the second input of which is connected to the output of the amplifier of the second intermediate frequency, a narrow-band filter, and the second phase to the second moreover, the second mixer is connected in series to the key output, the second input of which is connected to the output of the second local oscillator, and the amplifier of the second intermediate frequency.

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