SU475633A1 - Multistable device-correl to the throne - Google Patents

Description

one

The invention relates to the field of analog computing and automation and can be used in radio engineering as a device with many stable states for stabilizing the modes of generating complex radio signals using electro-optical means.

The proposed multistable device essentially opens up a new class of devices — a correlator, indicative of steady states in which are the types of complex radio signals widely used in modern radar, communications, ionospheric sounding, radio navigation, space research and measurement technology. Complex signals are radio signals whose product is the duration of which (for example, for radio pulses) and the width of their spectrum much greater than one. Thus, in modern radar, complex signals with intrapulse frequency modulation, phase-shift keyed signals in accordance with the Barker, Frank, Huffman codes, and other noise-like binary M-sequences having a base from several tens to several tens and thousands of hours and Woodward-defined uncertainty functions of various structures. Processing of such signals is usually carried out using correlation devices or matched complex filters. As a result of correlation processing, the signal is severely compressed in time and increases sharply in amplitude, which ensures the separation of such signals against a background significantly higher than the level of interference, i.e. the creation of highly interference-resistant and hidden radio systems. In recent years, the methods of optical processing of complex radio-technical signals based on the creation of multichannel optical-acoustic correlation devices, as well as methods of generating complex signals based on optical-acoustic correlators have been widely used.

The prototypes for the described device based on the principle of constructing an optoacoustic correlation multichannel circuit can be the well-known multi-channel correlator containing a source of monochromatic light, such as an optical continuous-wave quantum generator, a collimator, a spatial multi-channel diffractive light modulator of an optical-acoustic type, a multichannel reference transparency, channel-integrating cylindrical (astigmatic) lens and channel photoapplication, installed in the local plane of the specified lens in places

dislocations of the first diffraction orders of the corresponding channels of the correlator.

The known device works as a correlation and is intended for processing complex signals of various kinds (by the number of channels). To use the correlator as a generator of complex signals, it is sufficient to excite a short acoustic wave train in the sound conduit of a spatial diffraction modulator for the corresponding channel of it. In this case, its acoustic conduction in the form of a delta pulse at the intermediate frequency optically “records” the recording on the corresponding donor of the reference transnaranta (a certain kind of complex signal is recorded on each track of the banner). At the output of the corresponding channel photodetector, the corresponding component of a complex electrical signal is allocated as a function of time transferred to the intermediate frequency, i.e., the spatial recording of the reference signal on the corresponding transnranrant track is transformed into a time radio pulse whose duration is distributed across the acoustic train in the aperture spatial diffraction modulator (time of “poll of the recording on the transparency).

However, the known device cannot operate in the autonomous generator mode, it is characterized by complexity.

The purpose of the invention is to generate a periodic sequence of complex radio signals of various kinds. For this, the spatial diffractive light modulator of an optoacoustic type is single-channel one-way and installed between the additionally introduced two cylindrical lenses so that the line of their common focus is aligned with the acoustic wave propagation path of the optical-acoustic optic light modulator that is optically connected to the multichannel reference transparency with the spatial images of the generated complex signals recorded on it through electro-optical multiband polarization Ion light modulator, coupled to the pulse switch for generating channels and light analyzer plate, while the output reference multichannel transparency is optically coupled through a spherical lens with a photodetector common to all channels used. The output of the photographic parallel is connected to the band amplifier and the maximum limiter with a low-impedance load connected to the input of the single frequency vibrator of the intermediate frequency, the outputs of the one-shot and bandpass amplifier are connected to the piezoelectric sensor of the specified optical-optical light modulator through an adder.

The drawing shows a functional diagram of the throne correl.

The device contains a source of coherent light 1, for example, an optical quantum continuous generator, a collimator 2, an opto-acoustic cell 3 of an opto-acoustic spatial diffraction light modulator, the sound conductor of which is excited by an piezosensor 4 in the form of an acoustic wave, then absorbed by an acoustic absorber 5, a pair of cycliprical

(astigmatic) lenses 6 and 7, the common focus lines of which are combined with the propagation path of the acoustic wave in the sound channel of the cuvette 3, electrophoretic polarized (multiband) polarization

light modulator 8 based on electro-optic crystals located in an electrical field created on the corresponding output of the pulse switch 9 generation channels, plastip-analyzer

10 light (dichroic film polaroid), the main polarization plane of which is crossed from the polarization plane of the light emitted by the source 1 (the radiation of gas laser devices is strictly

polarized in the plane). In addition, the device contains a multi-channel reference transparency 11 with spatially recorded (in phase or amplitude of light waves passing through it) supporting complex

signals of various kinds, a spherical integrating lens 12, a photodetector 13 installed in the focal plane with a lens in the location area plus or minus the first diffraction pattern of the diffraction pattern, an intermediate frequency band amplifier 14 and a maximum limiter 15 of maximum magnitude connected in parallel to the photo-output. 2. The output of the limiter 15 is associated with a low-impedance load 16, which shunts the output of the photodetector 13 at signals exceeding a certain threshold value at the output of the photon detector. This load is connected to the single frequency delta pulses 17 of the intermediate frequency, and the outputs of the single vibrator 17 and the band amplifier

14 are connected through the adder 18 to the piezoelectric transducer 4 of the diffraction diffraction

light modulator.

Consider the effect of the proposed device.

A linearly polarized monochromatic wolf of the light of an optical quantum generator I is formed by the collimator 2 in the form of a plane light wave, which acts on the acoustic duct of the optical-acoustic cell 3, excited by the ultrasonic wave from the piezo-sensor 4. Then it is absorbed in the acoustic absorber 5, so that the sound conductor will flow out of the sensor. acoustic wave when applied to the piezoelectric sensor corresponding electrical oscillations. The propagation path of the acoustic wave in the sound pipe of the cuvette 3 is aligned with the common line of foci of cylindrical (astigmatic) lenses 6 and 7. Therefore, the wave front

The luminous flux at the output of the lens 7 is phase-modulated when an acoustic wave propagates in the flux tube of the cuvette 3, which causes corresponding disturbances in the flux density of the flux duct. The use of a single-channel opto-acoustic modulator equipped with cylindrical (astigmatic) lenses 6 and 7, is adequate to the use of a multichannel optic-acoustic modulator without liiz, however, the design is much simpler and more reliable than the latter.

Switching on one or another generation channel is achieved by applying to the appropriate translucent strip (electrically conductive) of an electro-optical multiband polarization modulator 8 light of an electric potential of a certain amount from the pulse switch 9 of the generation channels relative to the common electrically conductive semi-transparent grounded plate of the flat crystal plate of the polarization modulator ( made of potassium or ammonium dihydrophosphate, lithium niobate, barium titanate or trontium, zinc sulphide, etc.). The direction that opens the corresponding generation channel, called the half-wave and is equal in order from several tens to several hundred volts, changes the magnitude of the anisotropy of the crystal (its honor in the form of a band). That the light flux passing in this channel changes its polarization by 90 °. For all other channels of the device, the light does not change the nature of its polarization. Since the analyzer plate 10 is installed behind the polarization modulator, the main plane of polarization is orthogonal to the plane of polarization of the light of the optical quantum generator 1, the light at the output of the platinum analyzer can pass only in the channel under consideration associated with one of the recorded multichannel reference transparency of 11 phase or amplitude tracks. Consequently, by changing the connection of the half-wave voltage from the switch 9 to one or another electrically conductive semi-transparent strip of the polarization modulator 8, the light flux diffracted in the spatial optical-acoustic modulator can be directed through one or another channel of the multichannel reference transparency when all other channels.

Implementation of selective switching of channels of a multichannel reference transparency allows replacing a cylindrical (astigmatic) lens integrator and channel photodetectors, the number of which is equal to the number of transparency channels, to a spherical integrating lens 12 and one photodetector 13, common to all channels of the correlator, mounted in the focal plane of the lens 12 in the dislocation region, plus or minus the first diffraction order. When used

The spherical integrating loop 12 coordinates of the diffraction region of the MaKCHMyNtoB diffraction pattern are the same for all the kaials of the correlator. Because of this, you can do with one common photodetector.

The process of double (sequential) diffraction of a light wave on the acoustic conductor of the ontico-acoustic light path and on the corresponding multichannel track

the reference transparency and integration in a spherical lens 12 characterizes the process of taking the correlation integral over the optical system aperture from two functions — the signal supplied to piezo sensor 4, and the signal spatially displayed on the corresponding phase or amplitude multichannel reference banner. The theory and experiment show that if a short train of electrical oscillations of an intermediate frequency (spatially displayed on paths of a banner 11) is applied to a piezo sensor 4, then at the output of a photodetector 13 oscillations are formed at an intermediate frequency, having a spectrum of a complex signal recorded on the corresponding (open through the light flux ) transparency path. The duration of this signal is equal to the propagation time of the acoustic

Zug in the sound tube of the cuvette 3 within the working aperture of the optical system (time "delta pulse polling of the spatially distributed recording of the reference complex signal on the corresponding track is a scratch mark). On the other hand, if the oscillation of the corresponding complex signal is applied to the piezo sensor, 1a of the specified duration, the form of which coincides with that recorded on the running track

complex signal, then in the maxim of the correlation of the spatial distributions of the signal, the one converted into an optical-acoustic cell and recorded on the working track of the reference transparency,

The output of the photodetector 13 forms a "time-compressed pulse of large amplitude. So. if the base of the signal recorded on the transparency and supplied to the piezo-sensor 4 of the cuvette 3 is equal to S 100, then the duration

The compressed radio pulse at the output of the photodetector can be 100 times less than the duration of the signal being processed, determined by the aperture of the system, and the amplitude of the compressed pulse increases due to the law of conservation of energy 10 times compared to the amplitude of the complex radio pulse being processed.

Thus, this device can operate in two modes: generating

a complex signal recorded on the corresponding working path of a multi-channel, a basic support transparency, as well as processing of a complex radio pulse with the formation of a “compressed radio pulse of large amplitude. The choice of a particular mode depends

only on the nature of the signal applied to the pickup sensor 4 - a delta pulse of intermediate frequency from the output of the one-shot or a complex signal from the nosy amplifier 14.

The throne correlating circuit shown in the drawing is an equivalent quadrupole with non-monotonic amplitude response, closed in a feedback loop. The feedback is created by the fact that the output of the photodetector 13 is connected to the recording input of the spatial diffraction modulator of light — with the piezoelectric sensor 4 — through corresponding parallel acting formation and emission circuits (amplification). Such a scheme can be attributed to adaptive multidimensional recirculators with a hard self-excitation regime.

Indeed, if a triggering pulse from an external source is fed to the input of the one-shot 17 (along the launch bar), the piezo sensor is affected by a short radio pulse generated in the one-shot at the weft frequency (10-30 MHz), which in the sound duct of the cuvette 3 excites a short acoustic signal a train propagating in a cuvette and reading a recording of the reference complex signal from the running track of the banner 11. In this case, a component of the small radio signal read from the transparency appears at the output of the photodetector. and amplitudes of duration equal otnoscheniya working aperture of the optical system on the propagation velocity of acoustic waves in the acoustic line optoacoustic cell being read 3. It appears complex signal level substantially below the level of limitation in the limiter 15 to the maximum. Therefore, the output of the photodetector 13 is not shunted by the limiter 15 with a low-impedance load 16, and the signal affects only the bandwidth amplifier 14, is amplified in it and through the linear adder 18 again acts on the piezoelectric transducer 4.

Thus, a complex signal, read from the transparency I (with one of its working tracks), is again recorded in the sump of the spatial optical-acoustic modulator. This recording in the form of a traveling acoustic wave accumulates in the sound duct until the torus recorded in it coincides with the corresponding distribution of the reference complex signal on the considered path of the banner. This coincidence corresponds to the maximum correlation of the spatial records being mapped, and due to the previously stated at this time point, a very short ' compressed radio pulse with a large amplitude is formed at the output of the photodetector 13, substantially exceeding the limiter limit on the maximum. The limiter 15 opens, and the output of the photodetector is shunted by a low resistance of load 16, so that the feedback of the photodetector with piezoelectric 4 through a bandpass amplifier

14 has a temporary (during the "squeezed pulse") low transmission coefficient. The pulse signal, fixed in the resistance of the load 16, affects the input of the one-shot delta pulses of the intermediate frequency. At the same time, at its output a single very short radio pulse is formed at an intermediate frequency, which is fed to the piezoelectric transducer 4. The indicated

the process of regenerating the complex signal is repeated again.

Consider an example of the implementation of the correl of the throne. If Optoacoustic “juveta 3 is filled with an aqueous solution of ethyl alcohol, and

the working aperture of the optical system is 100 mm, the maximum correlation time is about 100 microseconds. Such a value may be the duration of the generated complex radio pulses. If on tracks of a multichannel reference transparency various complex radio pulses are recorded with intrapulse linear frequency modulation (LFM) characterized by different values of the rate of change of carrier frequency

fluctuations within the pulse duration, for example, 5, O, 5, 5, 6, O, ..., 9.5 MHz (i.e., ten values of the rate of change of frequency inside a pulse with a duration of 100 microseconds) at the average frequency of radio pulses in 25 MHz, then the equivalent bases of complex signals are respectively 500, 550, 600,. . ., 950. The maximally “compressed in duration” correlation responses (in the correlation processing of complex signals,

while acting on the piezoelectric sensor 4) the durations are respectively O, 20, O, 18, O, 17O, II μsec, and their amplitudes are higher than the amplitude of the complex signal, respectively, 22, 23, 24,. . .,. 30 times. Band Amp 14

should be tuned to a frequency of 25 MHz and have a transparency band in the range of 20-30 MHz, a piezo sensor should work in the same frequency band (usually the bandwidth of optical-acoustic diffraction modulators is up to half of the center frequency of the piezoresonator). The generated complex signals represent a periodic sequence of a mixture of a read delta pulse and

complex signal of a given type with a period

repeat 100 microseconds. Temporary gating of such an aggregate signal, which is formed at the output of the photodetector 13, allows for a temporary rejection of delta pulses (this device is not represented in the drawing), i.e., to clear the output signal of the correlator from these pulses. A decade switch controlled by external pulses is used to switch generation channels.

Subject invention

A multi-stable device is a correlating throne containing a coherent light source placed on one optical axis, a collimator, an optical-acoustic spatial diffraction modulator of light with a piezo sensor and an absorber, a reference transparency, an integrating lens and a photo-receiver, which is different in that in order to obtain a periodic sequence complex signals device, contains a limiter, one-shot, intermediate-frequency amplifier, adder, two cylindrical lenses placed on a common optical axis with Respectively after the collimator and after the spatial diffraction modulator

light, the piezoelectric sensor of which is connected to the output of the adder, a plate-analyzer of light and a multi-track polarization light modulator, placed respectively between the reference transparency and the second cylindrical lens, and a pulse switch connected to a multi-track polarization modulator; the inputs of the adder are connected to the outputs of a single vibrator and an intermediate frequency amplifier connected by an input to a photodetector connected to a limiter connected to a load resistor and to a single vibrator.

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