RU2314644C1 - Acoustic-optical receiver - Google Patents

Abstract

FIELD: radio-electronics, possible use for receiving, direction-finding, spectral analysis and detection of complex signals with phase manipulation.

SUBSTANCE: acoustic-optical receiver contains first, second and third antennas, frequency transformer, first and second heterodynes, first, second and third mixers, first, second and third amplifiers of intermediate frequency, first, second, third, fourth and fifth multipliers, first, second, third and fourth narrowband filters, first and second correlators, first and second threshold blocks, first, second and third keys, first and second phase detectors, first and second registration blocks, low frequency filter, laser, collimator, first, second and third Bragg cells, first and second lenses, first and second matrices of photo-detectors.

EFFECT: expanded functional capabilities of acoustic-optical receiver due to precise and unambiguous direction-finding of phase-manipulated signals source in two planes at stable frequency, equal to difference of heterodyne frequencies f_h2-f_h1=2f_up.

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Description

The proposed receiver relates to electronics and can be used for receiving, direction finding, spectral analysis and detection of complex signals with phase shift keying (PSK).

Acousto-optical receivers are known (ed. Certificate of the USSR No. 1.718.695, 1.785.410, 1.799.226, 1.799.227; RF patents No. 2.001.533, 2.007.046, 2.234.808; "Foreign radio electronics", 1987, No. 5, p. 51 and others).

Of the known devices, the closest to the proposed one is the “Acousto-optic receiver” (RF patent No. 2.234.808, Н04В 10/06, 2003), which is selected as a prototype.

The known receiver provides reception, spectral analysis, detection and direction finding of the radiation source of FMN signals in only one plane.

An object of the invention is to expand the functionality of an acousto-optical receiver by accurately and unambiguously determining the radiation source of the FMN signals in two planes.

The problem is solved in that an acousto-optic receiver containing a laser, in which a collimator, a first, second and third Bragg cell are sequentially installed on the path of the light beam, while the first lens is installed on the path of the diffracted first Bragg cell of the light beam in the focal plane of which the first matrix of photodetectors is placed, the second and third Bragg cells are located on the optical axis of the device close to each other with the same directions of propagation in them -terrorist waves offset from one another by an amount

Δx = V × τ _E ,

where V is the propagation velocity of acoustic waves,

τ _e - the duration of the elementary premises,

a second lens is installed on the propagation path of the second and third Bragg cells of the light beam diffracted by the second lens, in the focal plane of which the second photodetector array is placed, as well as the first antenna in series, a frequency converter, consisting of a series of the first local oscillator and the first mixer, the first intermediate frequency amplifier, the first correlator, the second input of which is connected to the output of the second intermediate-frequency amplifier, the first threshold block, the first key, the first phase anector and a first recording unit, a second antenna connected in series, a second mixer, the second input of which is connected to the output of the second local oscillator, a second intermediate frequency amplifier, a first multiplier, the second input of which is connected to the output of the first intermediate frequency amplifier, and a first narrow-band filter, the output of which is connected with a second input of the first phase detector, connected to the output of the first local oscillator, a second multiplier, the second input of which is connected to the output of the second local oscillator, and the second narrow-band filter, the output of which is connected to the second input of the first key, the second key is connected in series to the output of the first intermediate-frequency amplifier, the second input of which is connected to the output of the first threshold block, the third multiplier, the second input of which is connected to the output of the low-pass filter, the third narrow-band filter , a fourth multiplier, the second input of which is connected to the output of the second key, a low-pass filter and a second registration unit, piezoelectric transducers of the first, second and third the first Bragg cell is connected to the output of the second key, equipped with a third antenna, a third mixer, a third intermediate frequency amplifier, a second correlator, a second threshold unit, a third key, a fifth multiplier, a fourth narrow-band filter and a second phase detector, and a third is connected in series to the output of the third antenna a mixer, the second input of which is connected to the output of the second local oscillator, the third intermediate frequency amplifier, the fifth multiplier, the second input of which is connected to the output of the first amplifier the intermediate frequency, the fourth narrow-band filter and the second phase detector, the output of which is connected to the second input of the first recording unit, the second correlator is connected in series to the output of the first intermediate frequency amplifier, the second input of which is connected to the output of the third intermediate frequency amplifier, the second threshold block and the third key, the second input of which is connected to the output of the second narrow-band filter, and the output is connected to the second input of the second phase detector, the antennas are placed in the form of a geometric the angle at the apex of which is the first antenna of the first receiving channel, common to the antennas of the second and third receiving channels located in the azimuth and elevation planes, respectively.

The structural diagram of the proposed receiver is presented in figure 1; a frequency diagram explaining the principle of formation of additional reception channels is shown in figure 2; the relative position of the antennas is shown in figure 3; timing diagrams explaining the detection principle of the received QPSK signal is shown in FIG. 4.

The acousto-optic receiver contains in series the first antenna 1, the first mixer 6, the second input of which is connected to the output of the first local oscillator 4, the first intermediate frequency amplifier 8, the first correlator 14, the second input of which is connected to the output of the second intermediate frequency amplifier 9, the first threshold block 15, the first key 16, the first phase detector 17 and the first registration unit 18, the second antenna 2 connected in series, the second mixer 7, the second input of which is connected to the output of the second local oscillator 5, the second amplifier 9 of the intermediate frequency, the first multiplier 10, the second input of which is connected to the output of the first intermediate frequency amplifier 8, the first narrow-band filter 11, the first phase detector 17 and the first recording unit 18, connected in series with the third antenna 34, the third mixer 35, the second input of which is connected to the output of the second local oscillator 5, the third intermediate frequency amplifier 36, the fifth multiplier 40, the second input of which is connected to the output of the first intermediate frequency amplifier 8, the fourth narrow-band filter 41 and the second phase det a vector 42, the output of which is connected to the second input of the first recording unit 18, connected in series to the output of the first local oscillator 4, a second multiplier 12, the second input of which is connected to the output of the second local oscillator 5, and a second narrow-band filter 13, the output of which is connected to the second input of the first key 16 serially connected to the output of the first intermediate frequency amplifier 8, the second correlator 37 is connected in series, the second input of which is connected to the output of the third intermediate frequency amplifier 36, the second threshold block 38 and a third key 39, the second input of which is connected to the output of the second narrow-band filter 13, and the output is connected to the second input of the second phase detector 42, sequentially connected to the output of the first intermediate frequency amplifier 8, the second key 19, the second input of which is connected to the output of the first threshold unit 15, the third multiplier 25, the second input of which is connected to the output of the low-pass filter 28, the third narrow-band filter 27, the fourth multiplier 26, the second input of which is connected to the output of the second key 19, the lower filter 28 stot and a second registration unit 29. A collimator 21, first 22, second 30, and third 31 Bragg cells are sequentially installed on the path of propagation of the laser light beam 20, the piezoelectric transducers of which are connected to the output of the second key 19. The Bragg cells 30 and 31 are located adjacent to each other with the same acoustic directions in them waves offset from each other by

Δx = V × τ _E ,

where V is the propagation velocity of acoustic waves,

τ _e - the duration of the elementary premises.

On the propagation path of the diffracted Bragg cell 22 of the part of the light beam, a lens 23 is installed, in the focal plane of which a photodetector array 24 is placed. On the path of propagation of the part of the light beam diffracted by the Bragg cells 30 and 31, a lens 32 is installed, in the focal plane of which a photodetector array 33 is placed. Serially connected local oscillator 4 and mixer 6 form a frequency converter 3. Antennas 1, 2 and 34 are placed in the form of a geometric right angle, at the apex of which is the first antenna 1 of the first receiving channel, common to antennas 2 and 34 of the second and third receiving channels, located in the azimuth and elevation planes, respectively.

The suppression of false signals (interference) received at mirror and Raman frequencies is based on the use of three receive channels, the local oscillator frequencies 4 and 5 of which are spaced in frequency by 2 × f _up

f _g2 -f _g1 = 2 × f _up

and channel voltage correlation processing. The number of additional (mirror and combination) channels doubles (figure 2), but creates favorable conditions for their suppression.

For direction finding of the radiation source of the FMN signals in two planes, the proposed method uses the phase method in which the phase shifts between the signals received by antennas 1 and 2, 1 and 34 are

Δφ ₁ = 2π × d ₁ / λ × Cosγ,

Δφ ₂ = 2π × d ₂ / λ × Cosβ,

where d ₁ , d ₂ - measuring base (distance between antennas);

λ is the wavelength;

γ, β are the angles that determine the direction to the radiation source in the azimuthal and elevation planes, respectively.

The phase direction finding method is characterized by a contradiction between the requirements of measurement accuracy and the uniqueness of reference of angular coordinates. Indeed, according to the above expressions, the phase system is the more sensitive to changes in the angles γ and β the larger the relative sizes of the bases d ₁ / λ and d ₂ / λ. However, with increasing d ₁ / λ and d ₂ / λ, the values of the angular coordinates γ and β decrease at which the phase differences Δφ ₁ and Δφ ₂ exceed the value 2π, i.e. ambiguity of counting occurs.

The ambiguity of direction finding by the phase method can be eliminated in two classical ways:

1) the use of highly directional antennas;

2) using several measuring bases (multiscale).

Direction finding systems with highly directional antennas have a long range and high resolution in direction. However, they require a search for the radiation source before the start of measurements and its tracking in the direction of the antenna beam during the measurement process.

The multi-scale method of reading angles is based on the use of several measuring bases. At the same time, smaller bases form coarse, but unequivocal reference scales, and large bases form accurate, but ambiguous reference scales. Direction finding systems using this method have a limited range and a complex antenna system.

The proposed device uses a correlation method to eliminate direction finding ambiguity, which uses the remarkable properties of FMN signals.

A necessary condition for the synchronous detection of PSK signals is the presence of a constant initial phase and frequency at the receiving point of the reference voltage equal to the frequency of the received PSK signal.

In principle, three methods for obtaining the reference voltage are possible:

1) from a local generator;

2) using an auxiliary pilot signal transmitted on a separate channel;

3) directly from the received QPSK signal.

The first method does not provide the necessary in-phase and synchronized oscillations, since the phase and frequency of any highly stable generator changes under the influence of various destabilizing factors.

The second method of obtaining the reference voltage also did not find wide practical application, since its technical implementation leads to loss of spectrum and power in the channel for transmitting the pilot signal.

The proposed receiver uses a method for extracting the reference voltage directly from the received PSK signal.

To demodulate the received PSK signals, an acousto-optical demodulator can also be used, consisting of Bragg cells 30 and 31 mounted on the common optical axis of the receiver close to each other with the same directions of propagation of acoustic vibrations in them, lens 32 and photodetector matrix 33. Moreover, these cells are offset from each other (along the X axis) by

Δx = V × τ _E ,

where V is the propagation velocity of acoustic vibrations;

τ _e - the duration of the elementary premises of which the received PSK signal consists.

The use of an acousto-optical demodulator is possible only with an a priori value of the duration τ _{E of the} elementary premises.

Acousto-optic receiver operates as follows.

Received QPSK signals:

U ₁ (t) = υ _c × Cos [2π (f _c ± Δf) t + φ _k (t) + φ ₁ ],

U ₂ (t) = υ _c × Cos [2π (f _c ± Δf) t + φ _k (t) + φ ₂ ],

U ₃ (t) = υ _c × Cos [2π (f _c ± Δf) t + φ _k (t) + φ ₃ ], 0≤t≤T _C ,

where υ _c , f _c , φ ₁ , φ ₂ , φ ₃ , Т _C - amplitude, carrier frequency, initial phases and signal duration;

± Δf is the instability of the carrier frequency due to various destabilizing factors;

φ _k (t) = {0, π} is the manipulated component of the phase, which displays the law of phase manipulation in accordance with the modulating code M (t) (Fig. 4, a), and φ _k (t) = const at k × τ _Э <t <(k + 1) × τ _E and can change stepwise at t = k × τ _E , i.e. at the borders between elementary messengers (k = 1, 2, ..., N-1);

τ _E , N - the duration and number of chips that make up a signal of duration T _c (T _c = N × τ _E ); from the output of antennas 1, 2 and 34 are fed to the first input of the mixers 6, 7 and 35, respectively, the second input of which the voltage is applied from the output of the local oscillators 4 and 5

U _g1 (t) = υ _g1 × Cos (2πf _g1 t + φ _g1 ),

U _g2 (t) = υ _g2 × Cos (2πf _g2 t + φ _g2 ),

where υ _g1 , υ _g2 , f _g1 , f _g2 , φ _g1 , φ _g2 are the amplitudes, frequencies, and initial phases of the local oscillator voltages 4 and 5.

Moreover, the frequencies f _g1 and f _{g2 of the} local oscillators 4 and 5 are spaced at twice the intermediate frequency

f _g2 -f _g1 = 2 × f _up

and are selected symmetrical with respect to the carrier frequency f _{c of the} received signal

f _c -f _g1 = f _g2 -f _c = f _up .

This circumstance leads to a doubling of the number of additional receiving channels, but creates favorable conditions for their suppression due to correlation processing.

At the output of the mixers 6, 7 and 35, the voltages of the combination frequencies are formed. Amplifiers 8, 9 and 36 are allocated voltage intermediate (differential) frequency:

_Pr1 U (t) = υ _pr1 × Cos [2π (f _{ave ± Δf) t + φ k (} t) + φ _pr1]

_Np2 U (t) = υ _np2 × Cos [2π (f _{ave ± Δf) t + φ k (} t) + φ _np2]

_PR3 U (t) = υ _np2 × Cos [2π (f _{ave ± Δf) t + φ k (} t) + φ _PR3], 0≤t≤T _c,

where υ _pr1 = 1/2 × K ₁ × υ _c × υ _g1 ;

υ _pr2 = 1/2 × K ₁ × υ _c × υ _g2 ;

K ₁ - gear ratio of the mixers,

f _CR = f _c -f _g1 = f _g2 -f _c - intermediate frequency,

φ _pr1 = φ ₁ -φ _g1 ;

_np2 φ = φ ₂ -φ _r2;

_PR3 φ = φ _r2 -φ _3;

Voltages U _CR1 (t) and U _CR2 (t), U _CR1 (t) and U _CR3 (t) are supplied to two inputs of multipliers 10 and 40, at the output of which harmonic oscillations are generated

U ₃ (t) = υ ₃ × Cos (4πf _pr t + Δφ _g + Δφ ₁ ),

U ₄ (t) = υ ₃ × Cos (4πf _pr t + Δφ _g + Δφ ₂ ), 0≤t≤T _c ,

where υ ₃ = 1/2 × K ₂ × υ _pr1 × υ _pr2 ;

K ₂ - transmission coefficient of the multipliers;

Δφ _g = φ _g2 -φ _g1 ;

Phase shifts determining the direction to the radiation source

Δφ ₁ = φ ₂ -φ ₁ = 2π × d ₁ / λ × Cosγ;

Δφ ₂ = φ ₃ -φ ₁ = 2π × d ₂ / λ × Cosβ;

γ, β - azimuth and elevation,

which are allocated by narrow-band filters 11 and 41, respectively, and arrive at the first input of phase detectors 17 and 42, respectively.

The voltage U _g1 (t) and U _g2 (t) from the output of the local oscillators 4 and 5 are fed to two inputs of the multiplier 12, at the output of which a harmonic oscillation is formed

U ₅ (t) = υ ₅ × Cos (4π f _pr t t + Δφ _g ),

where υ ₅ = 1/2 × K ₂ × υ _g1 × υ _g2 ;

2f _ave = f _r2 -f _r1,

which is allocated by the narrow-band filter 13, the tuning frequency f _{n2 of} which is chosen equal to 2f _pr (f _n2 = 2f _pr ).

The _voltages U _CR1 (t) and U _CR2 (t), U _CR1 (t) and U _CR3 (t) simultaneously arrive at two inputs of the correlators 14 and 37, respectively, at the output of which voltages υ ₁ and υ ₂ are formed, which are proportional to the correlation functions R ₁ (τ) and R ₂ (τ). The indicated voltages are input to the threshold blocks 15 and 38, where they are compared with the threshold voltage υ _then . In this case, the threshold voltage υ _then in threshold blocks 15 and 38 is exceeded only at the maximum output voltage of the correlators 14 and 37 (υ _max1 > υ _pore , υ _max2 > υ _pore ). Since the channel voltages U _CR1 (t) and U _CR2 (t), U _CR1 (t) and U _CR3 (t) are formed by the same PSK signal received on the main channel at the carrier frequency f _c , between them there strong correlation. The output voltages of the correlators 14 and 37 exceed the threshold level υ _pores in the threshold blocks 15 and 38.

When the threshold voltage υ _pores is exceeded, constant voltages are formed in the threshold blocks 15 and 38, which are supplied to the control inputs of the keys 15, 19 and 39, opening them. In the initial state, the keys 15, 19 and 39 are always closed.

In this case, the harmonic voltage U ₅ (t) from the output of the narrow-band filter 13 through the public keys 16 and 39 is fed to the second input of the phase detectors 17 and 42, at the output of which constant voltages are generated

U _n1 (γ) = υ _n × CosΔφ ₁ ,

U _n2 (β) = υ _n × CosΔφ ₂ ,

where υ _n = 1/2 × K ₃ × υ ₃ × υ ₅ ;

To ₃ - the transfer coefficient of phase detectors.

These voltages are recorded by the registration unit 18. Moreover, improving the accuracy of direction finding of the radiation source of the FMN signals in two planes is provided by increasing the measuring bases d ₁ and d ₂ . And the resulting ambiguity in the reading of the angles γ and β is eliminated by the correlation processing of channel stresses.

The width of the spectrum Δf _{c of the} received QPSK signals is determined by the duration τ _{E of the} chips (Δf _c = 1 / τ _E ), while the width of the spectrum Δf _{g of} harmonic oscillations U ₃ (t) and U ₄ (t) is determined by their duration T _c (Δf _g = 1 / T _s ), i.e. the spectrum of input QPSK signals is convoluted N times (Δf _c / Δf _g = N). This makes it possible to select harmonic oscillations U ₃ (t) and U ₄ (t) using narrow-band filters 11 and 41, filtering out a significant part of noise and interference, i.e. to increase the real sensitivity of the receiver during direction finding of the radiation source of the FMN signals in two planes.

The voltage U _pr1 (t) (Fig. 4, b) from the output of the intermediate frequency amplifier 8 through the public key 19 is simultaneously supplied to the piezoelectric transducer of the Bragg cells 22, 30 and 31, where it is converted into acoustic vibrations, and to the first inputs of the multipliers 25 and 26 . The second input of the multiplier 26 from the output of the narrow-band filter 27 is supplied with a reference voltage (Fig. 4, c)

U ₀ (t) = υ ₀ × Cos (2πf _prt + φ _pr1 ), 0≤t≤T _c .

As a result of multiplication, the resulting voltage is formed

U _∑ (t) = υ ₁ × Cosφ _k (t) + υ ₁ Cos [4πf _pr t + φ _k (t) + 2φ _pr1 ],

where υ ₁ = 1/2 × K ₂ × υ _pr1 × υ ₀ .

Analog modulating code (figure 4, g)

U _n (t) = υ ₁ × Cosφ _k (t)

allocated by the low-pass filter 28, registered by the registration unit 29 and fed to the second input of the multiplier 25, the output of which is harmonic oscillation

U ₆ (t) = υ ₆ × Cos (2πf _pr t + φ _pr1 ) = υ ₀ × Cos (2πf _pr t + φ _pr1 ),

where υ ₆ = 1/2 × K ₂ × υ _pr1 × υ ₁ ; υ ₆ = υ ₀ .

This voltage is allocated by a narrow-band filter 27 and applied to the second input of the multiplier 26. Thus, synchronous detection of the received PSK signal is carried out.

The beam of light from the laser 20, collimated by the collimator 21, passes through the Bragg cells 22, 30 and 31 and diffracts on acoustic vibrations excited by voltage U _pr1 (t).

It should be noted that approximately 1/10 of the main light beam is diffracted on each Bragg cell. Each Bragg cell consists of a sound duct and a hypersonic exciting piezoelectric plate made of a lithium niobate crystal, respectively, X and Y - 35 ° cut. This provides an automatic add-on Bragg angle and cell operation in a wide frequency range.

On the propagation path of the diffracted Bragg cell 22 of the part of the light beam, a lens 23 is installed, which forms the spatial spectrum of the received QPSK signal, in the focal plane of which a matrix of 24 photodetectors is placed. These elements form an acousto-optical spectrum analyzer.

Bragg cells 30 and 31, mounted on the common optical axis of the device close to each other with the same directions of propagation of acoustic vibrations in them, the lens 32 and the photodetector matrix 33 form an acousto-optic demodulator of the received FMN signal (Fig. 4, e, f). Moreover, these cells are offset from each other (along the X axis) by

Δx = V × τ _E ,

where V is the propagation velocity of acoustic vibrations;

τ _e - the duration of the elementary premises of which the received PSK signal consists.

Moreover, the reference voltage for each subsequent elementary package is the previous package. Practical implementation of the acousto-optical demodulator is possible only if a priori knowledge of the duration of τ _e chip.

The operation of the receiver described above corresponds to the case of receiving QPSK signals on the main channel at a frequency f _s (FIG. 2).

If a false signal (interference) is received through the first mirror channel at a frequency f _s1 , then in mixers 6, 7 and 35 it is converted to voltages of the following frequencies:

f ₁₁ = f _g1 -f _z1 = t _up ,

f ₁₂ = f _g2 -f _z1 = 3f _up ,

where - the first index denotes the channel through which a false signal (interference) is received;

- the second index denotes the number of the local oscillator, the frequency of which is involved in the conversion of the carrier frequency of the received false signal (interference).

However, only the voltage at the frequency f ₁₁ falls into the passband of the intermediate frequency amplifier 8, and then is fed to the first input of the multipliers 10, 40 and correlators 14 and 37. The output voltage of the correlators 14 and 37 is zero, since the voltage at the output of the amplifiers 9 and 36 intermediate frequency is missing. The keys 16 and 19 do not open and a false signal (interference) received on the first mirror channel at a frequency f _s1 is suppressed.

If a false signal (interference) is received via the second mirror channel at a frequency f _s2 , then in mixers 6, 7 and 35 it is converted to voltages of the following frequencies:

f ₂₂ = f _z2 -f _g2 = f _up ,

f ₂₁ = t _z2 -f _g1 = 3f _up .

However, only voltage with frequency t ₂₂ falls into the passband of amplifiers 9 and 36 of intermediate frequency and to the second input of correlators 14 and 37. The output voltage of correlators 14 and 37 in this case is also equal to zero, since there is no voltage at the output of amplifier 8 of intermediate frequency. The keys 16 and 19 do not open and a false signal (interference) received on the second mirror channel at a frequency f _s2 is suppressed.

For a similar reason, false signals (interference) received through other additional channels are also suppressed.

If false signals (interference) are received simultaneously on the first and second mirror channels at frequencies f _s1 and f _s2 , then in mixers 6, 7 and 35 they are converted to voltages of the following frequencies:

f ₁₁ = f _g1 -f _z1 = t _up , f ₂₂ = f _z2 -f _g2 = f _up , f ₁₂ = f _g2 -f _z1 = 3f _up , f ₂₁ = t _z2 -f _g1 = 3f _up .

In this case, voltages with frequencies f ₁₁ and f ₂₂ fall into the passband of amplifiers 8, 9 and 36 of intermediate frequency and to two inputs of multipliers 10, 40 and correlators 14, 37. However, the keys 16 and 19 do not open. This is because different false signals (interference) are received at different mirror frequencies f _s1 and f _s2 , so there is a weak correlation between the channel voltages allocated by the amplifiers 8, 9 and 36 of the intermediate frequency. In addition, it should be noted that the correlation function of interference does not have a pronounced maximum, as is the case with complex PSK signals. The output voltages υ ₁ and υ _{2 of the} correlators 14 and 37 do not exceed the threshold voltage υ _pores in the threshold blocks 15 and 38 (υ ₁ <υ _pore , υ ₂ <υ _pore ). The latter do not work, the keys 16, 19 and 39 do not open and false signals (interference), received signals (interference), received simultaneously on the first and second mirror channels at frequencies f _s1 and f _s2 , are suppressed.

For a similar reason, false signals (interference) received simultaneously on other additional (combinational) channels are also suppressed.

Therefore, by suppressing false signals (interference) received via additional (mirror and Raman) channels, the noise immunity and resolution of the receiver are improved. At the same time, synchronous demodulators of FMN signals of freedom from the phenomenon of “reverse work”, which is inherent in the well-known devices of A. A. Pistolkors, V. I. Siforov, D. F. Kostas and G. A. Travin.

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 (azimuthal and elevation). Moreover, accurate direction finding is achieved by increasing the relative size of the measuring bases d ₁ / λ, d ₂ / λ. And the ambiguity of the reading of the angular coordinates γ and β arising from this is eliminated by correlation processing of the received PSK signals. Direction finding of the radiation source of the FMN signal is carried out in two planes at a stable frequency, equal to the frequency difference of the local oscillators f _g2 -f _g1 = 2f _up . In addition, the instability of the carrier frequency caused by various destabilizing factors is eliminated. Thus, the functionality of the acousto-optical receiver is expanded.

Claims (1)

An acousto-optic receiver containing a laser, the collimator, the first, second and third Bragg cells are sequentially mounted on the path of the light beam, while the first lens is installed on the path of the diffracted first Bragg cell of the light beam, in the focal plane of which the first photodetector array is located, the second and the third Bragg cell are located on the optical axis of the device close to each other with the same directions of propagation of acoustic waves in them, offset by each other the value of Δх = V × τ _Э , where V is the propagation velocity of acoustic waves, τ _Э is the duration of elementary premises, a second lens is installed on the propagation path of the second and third Bragg cells of the light beam, in the focal plane of which there is a second photodetector array as well as series-connected first antenna, frequency converter, consisting of series-connected first local oscillator and first mixer, first intermediate frequency amplifier, first correlator, second input to of which is connected to the output of the second intermediate frequency amplifier, the first threshold unit, the first key, the first phase detector and the first registration unit, the second antenna connected in series, the second mixer, the second input of which is connected to the output of the second local oscillator, the second intermediate frequency amplifier, the first multiplier, the second the input of which is connected to the output of the first intermediate frequency amplifier, and the first narrow-band filter, the output of which is connected to the second input of the first phase detector, is sequentially directed to the output of the first local oscillator, a second multiplier, the second input of which is connected to the output of the second local oscillator, and a second narrow-band filter, the output of which is connected to the second input of the first key, and a second key in series with the output of the first intermediate frequency amplifier, the second input of which is connected to the output of the first threshold block, the third multiplier, the second input of which is connected to the output of the low-pass filter, the third narrow-band filter, the fourth multiplier, the second input of which is connected to the output the second key, a low-pass filter and a second registration unit, the piezoelectric transducers of the first, second and third Bragg cells are connected to the output of the second key, characterized in that it is equipped with a third antenna, a third mixer, a third intermediate frequency amplifier, a second correlator, a second threshold block, the third key, the fifth multiplier, the fourth narrow-band filter and the second phase detector, and the third mixer is connected in series to the output of the third antenna, the second input of which is connected to the second local oscillator, the third intermediate frequency amplifier, the fifth multiplier, the second input of which is connected to the output of the first intermediate frequency amplifier, the fourth narrow-band filter and the second phase detector, the output of which is connected to the second input of the first registration unit, the second is connected in series to the output of the first intermediate frequency amplifier a correlator, the second input of which is connected to the output of the third intermediate frequency amplifier, the second threshold block and the third key, the second input of which is connected to the output of the second narrow-band filter, and the output is connected to the second input of the second phase detector, the antennas are placed in the form of a geometric right angle, at the top of which is the first antenna of the first receiving channel, common to the antennas of the second and third receiving channels, located in the azimuth and elevation planes, respectively.

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