RU51757U1 - MULTI-PARAMETER FIBER-OPTICAL INFORMATION-DIAGNOSTIC TRANSMISSION SYSTEM - Google Patents

Abstract

The invention may used in close to straight-line, fiber-optic communication lines that may subject to unauthorized access, ionizing radiation or fur. exposure. Tech. the result is increased information security in a fiber optic communication system. It is achieved by the fact that a reflection unit, controlled by the encryption gamma obtained on the basis of a common key, is added to the system, which changes the conditions of its reflection when the OTDR passes through it. The OTDR pulse is formed at the wavelength determined by the encryption gamma. To exclude the possibility of preliminary scanning of the reflection unit by generating a signal at all wavelengths of the OTDR and mismatching the equipment at both ends of the optical fiber, a scanning identification unit, a delay unit, a reference generator, and a generator tuning unit have been introduced. The design and algorithms of the OTDR and the resolver are also amended to ensure the achievement of the goal.

Description

The invention relates to fiber-optic communication technology and can be used to transmit signals in systems whose communication lines may be subject to unauthorized access, either by ionizing radiation or mechanical stress, in all cases where constant monitoring of the quality of the communication channel is required and in addition to determining of the fact of external influence, it is necessary to find the site itself on which this effect occurred, for example: when organizing fiber-optic communication between computers when they need to maintain confidentiality and reliability of the exchange of information between jobs; in cases where communication is not possible due to fiber damage, and in a short time it is necessary to identify the place of occurrence of the malfunction and eliminate it; in systems operating in hazardous areas in which a fiber cable can be exposed to ionizing radiation and so that this does not affect the quality of communication to restore the irradiated line.

Known (Pat. 2128885 Russia, IPC {6} N 04 B 10/00. Military Acad. Strategic Rocket Forces named after Peter the Great. N 97102852/09; Declared 24.2.97; Publ. 10.4.99, Bulletin N 10. RU) a fiber-optic information-diagnostic transmission system, comprising: a transmitter, an optical input unit of a transmitter with three inputs, and a receiver connected by an optical cable (OK) (the transmitter contains an information source whose output is connected with the input of the electron-optical converter, the output of which, through the optical signal input unit, is connected to OK), the opposite end of which is connected to the photodetector of the information

signal. The transmitter includes a two-channel optical reflectometer (DOR) operating at two wavelengths, the output of which is connected to the second input of the optical signal input unit, a resolving device (RU), a pulsed optical generator, and an optical generator trigger pulse generation unit. The digital output of the DOR is connected to the input of the RU, one of the outputs of which is connected to the control input of the DOR, and the second output of the RU is connected to the input of the pulse generation of the pulse optical generator, the optical output of which is connected to the third input of the optical signal input unit. The structure of the DOR includes: a spectral divider, a Y-shaped optical connector and two controlled valves. The inputs of the Y-shaped connector are optically connected to the optical outputs of the electron-optical converter and the DOR, and the output of the connector is optically connected to the first input of the DOR beamsplitter, the second output of which is connected by an optical fiber (OB) to the input of the spectral divider, the outputs of which are optically coupled to the corresponding photodetectors. The outputs of the photodetectors are connected to the information inputs of the first controlled valve, and the information outputs of the second controlled valve are connected to the inputs of the electron-optical converter and DOR. The output of the first valve is connected to the input of the DOR signal processing and generation unit, one output of which is connected to the signal input of the second valve, and the second with the input of the switchgear, and the control inputs of both valves are connected to the first output of the switchgear. As part of the switchgear, there are sequentially between the output of the input buffer memory and the input of the operational-logical unit a normalization unit, a logarithm unit, and a differentiating unit. The first output of the operational-logical unit through a digital-to-analog converter is connected to the control inputs of the DOR gates; the second at the input of the processing unit and the generation of DOR signals, and the outputs of the RAM are connected to the second inputs of the normalization unit and the differentiating unit. Such a system, along with the transmission of information, makes it possible to diagnose the state of OK, to detect the fact of exposure to its ionizing radiation, to detect

deterioration of communication quality due to a change in the cable’s own attenuation, to determine the location of damage to the cable or to the area exposed to radiation, to increase the reliability of the line under conditions of exposure to ionizing radiation. Also, sometimes, such a system allows you to identify and determine the fact and place of unauthorized access to OM.

The disadvantage of this system is that in the absence of continuous monitoring of the state of the communication line, it allows for the organization of hard-to-detect relay, which consists in the inclusion of a repeater in the fiber optic communication line (FOCL) with the introduction of cable lengths that complement both cable lengths to the length of the original the way that their traces are identical.

The aim of the invention is to increase the security of information in fiber optic links.

This goal is achieved by the fact that an identical fiber-optic information-diagnostic transmission system in the opposite direction is additionally switched on, with the difference that the information is transmitted at a different wavelength along the same OB.

In addition, this goal is achieved by the fact that the radiation input device and the spectrally selective element are realized by a spectral demultiplexer / multiplexer (SM).

In addition, this goal is achieved by the fact that the composition of the fiber-optic information-diagnostic transmission system additionally includes: a generator adjustment unit (BPG), a reference generator (OG), a delay unit (BZ) and a reflection unit (BO). In this case, the output and input 1 of the gas generator are connected respectively to the input and output of the exhaust gas 1, the inputs 2 and 3 of the gas generator are connected, respectively, to the output of the photodetector and the output of the information receiver, and the outputs 2 and 3 of the exhaust gas are connected, respectively, to the input 2 of RU 5 and the input 2

electron-optical converter, in which changes have been made to control the generated optical signals. In the OB between the DOR and the SM, a BO is connected in series, the input of which is connected to the output of the BZ. The input of the BZ is connected to the output of the switchgear.

In addition, this goal is achieved by the fact that the composition of the decisive device containing an input buffer memory, a synchronizer, a control unit, a random access memory, an operational logic unit and an output buffer memory, a normalization unit, a logarithm unit, and a differentiating unit additionally include: a gamma control unit (BKG), the unit for determining the inclusion in the communication line (BOVLS), the source of the gamma encryption (IHS), the converter of the gamma encryption (PGS), the block of the direction of transmission (BNP), the block identification scan (LSI), the block alarm and inclusion in the communication line (BSVLS), key storage device (UHK) and station-type storage device (UHTS). In this case, the output is connected in series with the input: output buffer memory, BKG, BOVLS, IGSh, PGSh, BNP, BIS. In addition, the LSI output is connected to the second BOVLS input, the second BOVLS output is connected to the BSSL input, the UHF output is connected to the second IGBS input, the UHTS output with the second BNP input, and the second BNP output with the second BKG input. This allows continuous, simultaneous sensing, identification of the transceiver station at the opposite end of the OB by introducing more parameters into the backscattered signal. Under the transceiver station, we mean the complex of equipment available at each end of the OB.

In addition, this goal is achieved by the fact that the algorithm for the functioning of the DOR is changed. In addition, the following operations are performed: before generating a scanning pulse, obtaining from the RU the values of binary identification gamma and request, connecting a section of the BOFS DOR memory device (memory BOFS) corresponding to the values of binary identification and query gamma, waiting for a signal from the BNP RU to generate a scanning impulse; after saving the reflected signal in the digitalized BOFS memory in the digitized

form - checking the readiness of the switchgear to receive the trace, determining the estimated sample size; after saving reflectograms in the BOFS memory - memory is freed from unused reflected digitized signals; after receiving an unsatisfactory assessment of the accuracy of the trace - checking whether there is a possibility of increasing the sample size and, if there is one, increasing the sample size and returning to receiving the averaged reflected signal, and, if not, ignore the checking unit of satisfactory accuracy; after the trace is displayed, return to the operation of connecting the POM to the OB.

The principle of operation of the proposed system will be clear from a consideration of the functional diagrams of FIGS. 1-9 and the following description.

Figure 1 shows a functional diagram of one of two identical, with the differences previously agreed upon, halves of the system (previously called a transceiver station), available at one of the end points, which includes the following main elements: message source 1, electron-optical converter 2, CM 3, DOR 4, RU 5, triggering pulse formation circuit 6, pulsed optical generator 7, matching device 8, supply 0V 9, optical connector 10, OK 11, photodetector 14, information receiver 15, BPG 50, OG 51, BO 52 , BZ 53.

Figure 2 presents the functional diagram of the reflectometer 4, consisting of a beam splitter 16, a spectrally selective element 17, photodetectors 18 and 19, a Y-shaped splitter 20, emitters 21 and 22, valves 23 and 24, a signal processing and signal conditioning unit 25, and also a display 26 and a signal indicator device 27.

Figure 3 shows a diagram of a resolving device 5, which includes the following main elements: input buffer memory 29, normalization unit 30, logarithm unit 31, differentiating unit 32, operational logic unit 33, random access memory 34, control unit 35, synchronizer 36, analog-to-digital converter 37 and output buffer

memory 38, БКГ 54, БОВЛС 55, ИГШ 56, ПГШ 57, БНП 58, БИС 59, БСВЛС 60, УХК 61, УХТС 62.

Figure 4 shows an exemplary functional diagram of BOFS DOR, which includes the following main elements. Control unit BOFS 63; calculator 64; storage device 65, analog-to-digital converter BOFS 66.

Figure 5 shows an exemplary block diagram of the work of the DOR, which implements a pulsed location method (backscattering method [10]), which is installed on the materials [1, 2, 3, 4, 5].

Figure 6 presents an exemplary improved block diagram of the work of the DOR, which implements a pulsed location method (backscattering method).

7 is a functional diagram of a pulse generator 7 and matching device 8, which include the following main elements: laser active substance (ruby rod) 39, mirrors 40 and 41, flash lamp 42, switching power supply 43, delay element 44, optical shutter 45, collimator 46 and focus 47.

On Fig depicts an exemplary block diagram of the functioning of the proposed system and the solver 5 in conditions where the cable 11 in two, not closed sections, is exposed to ionizing radiation.

Fig. 9 shows an exemplary scheme for turning on an intruder in a mode of hard-to-detect relay, which includes the following main elements: a transceiver station at the near end of the OB (PPSBKOV) 70, a transceiver station at the far end of the OB (PPSKOV) 74, transceiver the intruder’s transmitting station at the far end of the OV (PPSNDKOV) 73, the intruder’s transmitting station at the near end of the OV (PPSNBKOV) 71, the information substitution implementation device (URPI) 72.

Electron-optical converters 2 operate at different wavelengths within the transparency windows for the used OM, one of which is selected near the cut-off wavelength of the corresponding OM. Input device

radiation 3 is CM.

As a basis for DOR, for example, a set of optical reflectometry boards can be used that realize the OM control simultaneously with the transmission of information issued by FSUE Concern SISTEMPROM or another manufacturer and mounted on a computer.

The decisive device 5 can also be implemented on the basis of a computer, by entering into it a special program, the structure of which is discussed below, as well as controlling the valves 23, 24, БЗ 53 with the signal device 27 and analog-to-digital converters for acquiring information from photodetectors 18, 19.

The trigger pulse generation unit 6 is sequentially connected: a program-controlled pulse generator, for example, of type G5-75, which generates, in accordance with the commands given, pulses of variable frequency and duration, a voltage amplifier.

The pulsed optical generator 7 is a laser with an electro-optical shutter that is connected to the output of the voltage amplifier of the trigger pulse generating unit 6. The matching device 8 is sequentially arranged: a collimator that reduces the cross-sectional area of the output beam, and a focon welded with OV 9.

The main purpose of the elements indicated in FIG. 1 is as follows: the message source 1 generates an electrical signal containing the necessary information; an electron-optical converter 2 converts an electrical signal into optical radiation; SM 3 carries out wave multiplexing; the optical connector 10 allows you to disconnect the equipment during installation and regulation; OK 11 is a medium for the propagation of optical radiation; the photodetector of the photodetector 14 converts the optical radiation into an electrical signal; an information receiver 15 senses an electrical signal; BPG adjusts exhaust gas; OTDR 4 monitors the status of OK 11; RU 5 carries out general control of elements; BZ 53 delays the pulses controlling BO 52; BO 52 forms

changed conditions for the reflection of the scanning pulse; a pulsed optical generator 7 destroys the radiation color centers in the OB at the command of the start pulse generation block 6; matching device 8 inputs optical radiation into the optical fiber; OB 9 connects the matching device 8 and CM 3.

The main purpose of the elements of DOR 4 shown in FIG. 2 are as follows. The beam splitter 16 is intended for introducing optical radiation from emitters 21 and 22 into the optical fiber and outputting the reflected radiation from the optical fiber; a spectrally selective element 17 performs wave demultiplexing of the reflected signal; photodetectors 18 and 19 convert optical radiation into an electrical signal; The Y-shaped splitter 20 introduces optical radiation from emitters 21 and 22, which convert the electrical signal into a scanning pulse; gates 23 and 24 carry out switching between emitters 21 and 22; BOFS 25 controls the formation of the scanning signal and analysis of the reflected signal; a display 26 and a signal indicator device 27 display information.

The main purpose of the elements of RU 5 shown in FIG. 3 is as follows. The input buffer memory 29 is used for preliminary storage of information coming from the control unit and generating signals 25 of the OTDR 4. If necessary, this information is transferred either to the normalization unit 30 or to the operational memory 34 by the command of the control unit 35. The normalization unit 30 carries out normalization of numbers coming from the buffer memory 29 or random access memory 34 using the values of the constants stored in the main memory 34. In the block logarithm 31, the calculation of the natural logarithms of numbers constituents from the normalization unit 30 and the differentiator 32 produces numerical derivation function a given array of numbers that follow from the logarithm unit 31. The operation of the quantization step derivation value of the argument of this function is transferred from the main memory 34. The operation logic

unit (OLB) 33 performs arithmetic and logical operations for the analysis of an array of numbers (converted reflectograms) from the output of the differentiating unit 32 and, additionally, generates the measured value of the recognition gamma in the ADC 37. The synchronizer 36 and the control unit 35 carry out general control of the operation of the resolver 5, and the ADC 37 converts the analog electrical signals into digital codes generated by OLB 33, which are sent to the output buffer memory 38. BKG 54, comparing the value of the received recognition gamma from the output buffer pa yati 38 and the gamma value recognition of BNP 58 in the minimum allowable period of faultless operation, which is expressed in the minimum number of coincident gammas sequentially received symbols output from the buffer memory 38 and the gamma value recognition of BNP 58 generates a signal 55 in BOVLS on the results of comparison. UHK 61 stores the key, on the basis of which an encryption gamma is generated in signals from the synchronized exhaust gas 51 in the IHS 56, which is sent to the PGS 57, where it is converted to the request, direction and recognition gamma, and also formed in a pseudo-random time moment, taking into account the capabilities VOSOI, the scanning resolution pulse, which are sent to BNP 58, and BNP 58, depending on the type of station information (information on which end of the OB there is a specific complex) in UHTS 62, it commutes the direction it follows pulses from PGSh 57 between DOR 4 and BZ 53, as well as switching signals from photodetectors 18, 19 of DOR 4 to LSI 59. LSI 59 from signals from the BNP generates a result of comparing signals from photodetectors 18, 19, and the result is sent to BOVLS 55, in which, on the basis of signals from BIS 59 and BKG 54, it is concluded that there is an inclusion in the OM. With a positive conclusion, a signal is generated to prohibit the formation of gamma, as well as information about the presence of inclusion in the OB, which is displayed using BSVLS.

The main purpose of the elements shown in FIG. 4 of BOFS 25 is as follows. The control unit BOFS 63 controls the measurement of reflected

signal, its processing and display; the calculator 64 averages the measurement result in the corresponding section of the storage device 65, which is converted from analog to digital using the BOFS 66 ADC.

The main purpose of the elements of the pulse generator 7 and the matching device 8 shown in Fig. 7 are as follows. Mirrors 40 and 41 form a resonator in which the active substance of the laser 39 is placed. The active substance 39 is excited from a flash lamp 42, which is fed from a pulsed source 43. An optical shutter 45 is connected between the working substance and one of the mirrors and connected to a voltage amplifier of the signal driver unit start 6 through the delay element 44. The pump source 43 is connected directly to the output of the programmable generator of the forming unit 6. The delay of the pulse supplied to the shutter 45 is necessary in order to bake the most efficient mode of operation of the laser pumping system. Matching device 8 includes a collimator 46, which reduces the cross-sectional area of the output beam, and focon 47, welded with OB 9.

With a small aperture of the organic matter, the pulse generator 7 can be replaced by a semiconductor laser with a sufficient radiation power.

The proposed system operates as follows. At one of the two stations, the message source 1 generates an electrical signal containing the information necessary for transmission, which is fed to the input of the electron-optical converter 2. The electron-optical converter 2 contains amplification-matching elements and an optical emitter, for example, a semiconductor laser that generates radiation in a synchronized Exhaust gas 51 moment at a direct transmission wavelength. This radiation, with the help of a matching element (for example, a gradient lens) is introduced into the first arm of the SM and then through the optical connector 10 it enters into OB OK 11.

At another station, a signal is generated in the OB in the same way at a wavelength

of the reverse transmission, after the optical connector 10 the SM is demultiplexed, it is incident on the photodetector of the photodetector 14. In the photodetector 14, the optical radiation is converted into an electrical signal that the information receiver 15 receives. Based on the received information and the signal about the reception of the optical pulse, the OGG 50 corrects the exhaust gas 51. On another station performs similar operations for information at a direct transmission wavelength.

Along with the transmission of information in the system, the state of OK 11 is continuously monitored. For this, according to the RU 5 command, a DOR 4 is activated, which generates an optical pulse, which, through the second arm of the SM and optical connector 10, enters into OV OK 11. Propagating through OV OK 11, part of the radiation is scattered by the inhomogeneities of the core back to the DOR 4. Depending on the value of the gamma of the request, the OTDR 4 analyzes the state of the cable 11 at the corresponding wavelength. When the request gamma value corresponding to the request at the first wavelength, from the output of the BNP 58 of the deciding device 5, the control voltage is supplied to the valves 23 and 24, switching the valves 23 and 24 to such a state that the emitter is connected to the signal processing and signal generating unit 25 of the reflectometer 4 21 and a photodetector 18 operating at a first wavelength. When the gamma value of the request corresponds to the request at the second wavelength, from the output of the BNP 58 of the solver 5 to the valves 23 and 24, a control voltage is supplied that switches the valves 23 and 24 to such a state that the ADC 66 BOFS 25 and the control unit 63 BOFS DOR 4 are connected respectively, the emitter 22 and the photodetector 19, operating at a second wavelength. The signal from the control unit 63 BOFS through the valve 23 emitter 21 generates a scanning pulse, which through the Y-shaped splitter 20, the beam splitter 16, BO 52, CM 3 and the optical connector 10 is directed to OB OK 11. Reflected from the inhomogeneities (when passing the scanning pulse along the OB) or from BO 52 (at the opposite end of the OB), the signal from the OB, through

the optical connector 10, CM 3, BO 52, the beam splitter 16 and the spectrally selective element 17, is converted into a photodetector 18, and, through the valve 23 is transmitted to the ADC 66, where it is digitized under the control of the control unit 63. The digitized signal is sent to the section of the storage device 65 corresponding to the current values of the recognition and query gammas. If there is a signal of readiness for receiving the trace in the storage device 65, the calculator 64, under the guidance of the control unit 63, averages the measurement result in the corresponding section of the storage device 65. The averaging result is sent to the storage device 65, from where to the input buffer memory 29 and, through the control unit 63, on the display 26. With a different value of the recognition gamut, actions are performed similar to those described above, but with the difference that another section of the trace memory is connected. With the query gamma value corresponding to the query at the second wavelength, similar actions are performed as described above, but with the difference that the other two sections of the trace memory are connected, respectively. ARR 4. One of the wavelengths chosen near the cutoff wavelength is less than the information exchange wavelengths because, firstly, at shorter wavelengths the radiation sensitivity (change in optical loss per unit dose of radiation) of most modern OMs is greater than at large wavelengths that allows you to detect the fact of irradiation of the cable at lower radiation levels, and secondly, with bends or other mechanical impact, the optical signal at this wavelength is highlighted in the first place. Moreover, the length of the OK is such that it can be completely blocked by the dynamic range of DOR 4 at both wavelengths. It is obvious that the time interval between the moments of the formation of two successive reflectograms according to the algorithm indicated in Fig. 6 is determined by the speed of the solver and, obviously, it can be less than the accumulation time of the device -1 ... 3 min. The results of the analysis of the state of OV OK 11 in the form of four reflectograms (formed separately for each pair of request and recognition gamma values) are displayed on the display 26 of the OTDR 4 and, simultaneously, in digital

form through the output interface, they enter into the buffer memory 29 of the deciding device 5. At the opposite end of the OB with a delay generated by the KB 53, corresponding to the propagation time of the scanning pulse, at a wavelength corresponding to the value of the gamma of the request, changed conditions for the reflection of the scanning pulse are formed using BO 52, corresponding to the value of the recognition gamut; in addition, the BNP 58 connects the outputs of the photodetectors 18, 19 to the inputs of the LSI 59.

Each word of the code sequence coming from the OTDR 4 to the resolving device 5 is a number whose value is proportional to the intensity of the reflected signal at the input of the photodetector 19 (18). In a first approximation, we can assume that the signal at the input of the photodetector 19 is described by the laws of Bouguer-Lambert and Rayleigh:

a (t) = A ₀ · k _p · exp {-α ₀ * (t ₀ -t) * c}; (one)

where A ₀ is the amplitude of the probe pulse;

k _p is the Rayleigh scattering coefficient.

t is the delay of the reflected pulse relative to the probe, due to its direct and reverse passage through the OB;

α ₀ is the attenuation coefficient of OB, dB / km.

Expression (1) can be compared similarly, where the time coordinate is replaced by the spatial

a (t) = A ₀ · k _p · exp {-α ₀ * (x ₀ -x)};

where x is the distance from the input end OV of the cable 11, which corresponds to the level of optical power, proportional to the value of a.

DOR 4 is a digital device and therefore the value of the intensity of the reflected signal in it is determined with some discreteness in time (or, which is the same, in distance), the step of which depends on the resolution (duration of the probe pulse) of the device. Thus, the trace recorded in the buffer memory 29 of the decider 5 is

one-dimensional array of numbers - a [1: M], each of which is determined by the ratio:

a [j] = A ₀ * exp {-α ₀ * x _j }.

After that, processing of this array begins, which, according to the commands of the control unit 35, is entered into the normalization block 30. In the normalization block 30, the array is normalized in accordance with the operand:

a ^* [j] = a [j] / A ₀ ;

the value A ₀ comes from random access memory 34. In the logarithm unit 31, the natural logarithm a * [j] is calculated

ln {a * [j]} = - α ₀ * x _j .

In the differentiating block 31, the derivative of the discrete function ln {a * [j]) is determined (or, in other words, the attenuation ОВ is determined):

d / dx {ln (a ^* [j])} = [- α _j * x _j - (- α _j * x _j-1 )] / Δх = -α _j .

The value of Δx depends on the technical characteristics of the reflectometer, its resolution and is entered into the differentiating unit 32 from the main memory 34.

From the differentiating unit 32, the attenuation values -α _j associated with a specific part of the OB are transferred to the OLB 33 by the commands of the control unit 35, which analyzes the sequence of values of α _j using digital filtering methods [8] and, based on the analysis results, makes a conclusion about the state of the OB and the distribution of heterogeneities OK 11, as well as the measured level of reflection from the opposite end of the OB at a given wavelength of the request.

The sequence of operations and procedures performed by OLS 33 is as follows:

- the distribution of heterogeneities of various types (“reflecting objects”, “non-reflecting objects”, “zones of increased attenuation”) is determined by the methods of coordinated digital filtering [6];

- compares the distribution and levels of heterogeneity with the reference

within tolerance.

Let us now consider how the proposed system and the resolver 5 function in conditions when the cable 11 is exposed to ionizing radiation in two non-closing sections (Fig. 8). In this case, radiation color centers are formed in the OM, leading to an increase in radiation-induced losses of the irradiated sites. This will lead to the fact that on the trace, which is displayed on the display screen DOR 4, there are sections whose steepness (in absolute value) is greater than the steepness of unirradiated sections. The corresponding matched filter defines “zones of increased attenuation” as the totality of the areas in which the increase and decrease of attenuation occurs. The operator, already on the display screen 26, can specify the distance to the irradiated areas and their length.

After the census of the OTDR from the processing unit and the formation of the signal 25 of the OTDR 4, to the solver 5, its analysis begins in accordance with the program described above. In this case, at one of the steps of analyzing the distribution of inhomogeneities, a situation arises when the signal from the increased filter attenuation agreed with the beginning of the section exceeds the signals from the other matched filters and the threshold value, which means that the program “approached”, during the analysis, to the beginning area exposed to radiation (or other effects). The program “turns on” the counter and starts counting the number of steps, and, therefore, determining the length of the portion of the OB where the attenuation and α _j differs from the previous values. Further, as soon as the damping reduction section is detected in the same manner as described above, the counter of the number of discrete trace elements of the irradiated section OV “stops” and their total number in the irradiated section is determined. And the analysis process continues further until the program “reaches” the next break point of the trace reflecting the beginning of the second irradiated section.

At the end of the analysis of the entire trace, a determination is made

radiation-induced losses and absorbed dose in the irradiated areas according to the following algorithms:

determination of radiation induced losses

P = ΔL ₀ α _region

where ΔL ₀ = ΔI ₀ N

α _region - specific attenuation of the irradiated portion of the organic matter as the difference between the reference and real specific attenuation obtained in the program in accordance with the algorithm (Fig. 8)

ΔI is the quantization step along the length of the trace, determined by the resolution of the reflectometer,

N is the number of steps accumulated in the "counter" of the program, in the analysis of the irradiated portion of OV, in proportion to its length,

determination of absorbed dose

D = d ₀ ΔL

where d is the radiation sensitivity of the OV cable 11 - (P / m) determined experimentally in advance on modeling installations.

In addition, the program provides a section for calculating the distance to irradiated sites according to the algorithm

I = ΔI ₀ M

where M is the number of program steps up to the moment when the trace portion of the trace is detected with increasing attenuation.

The values of I, ΔL, P, and D, as well as information about the readiness for analysis of the trace from OLB 33, through ADC 37 and the output buffer memory 38 from RU 5, are sent to BOFS 25 DOR 4, which then generates control signals and outputs them on the display screen 26 DOR 4 for visual control of the indicated values.

After determining the total (in all areas) radiation-induced losses Ps, in OLB 33 this value is compared with the energy potential reserve of DOR 4 at a smaller wavelength - P _min by analyzing the difference P _min -Р _s . If the condition is met

P _min -P _s ≅ΔP (2)

where ΔР is a predetermined value determined by the reliability of the reception of the reflected and transmitted signal.

then OLB 33 generates a signal on DOR 4, which displays the corresponding information on the display, about the achievement of the maximum level of radiation-induced losses (which means, in addition to the possibility of unstable exchange of information between receivers and transmitters at the ends of the OB, a maximum decrease in the accuracy of reflectometry measurements, and therefore , the possibility of disruption of the control channel lack of unauthorized access to OB).

In addition, OLB 33 RU 5, depending on the number of irradiated sections of OK 11 and the dose D absorbed by them, generates a command entering the trigger pulse generating unit 6, generating pulses whose duration t _{i is} proportional to the dose absorbed by the i-th irradiated cable section, and their number is equal to the number of irradiated cable sections. The time interval between pulses ΔT _{i is} set depending on the relaxation (destruction) time of the radiation color centers. This interval depends on the material of the cable core and the radiation wavelength of the pulsed laser 7. In determining the duration ΔT _i , the power of the optical generator 7 and the distance that the pulse must travel in OB to the irradiated section are also taken into account. In a first approximation, the value of t _i can be determined from the relation

kD _i = t _i * P _gene * α ² _g * ΔL _i * I;

Where

k is the proportionality coefficient characterizing the effectiveness of the influence of the radiation of the generator 7 on the radiation color centers per unit length of ОВ determined experimentally for given types of ОВ and

radiation wavelengths of the generator 7;

P _gene - generator power 7;

α _g - linear attenuation of OB at the wavelength of the generator 7;

ΔL _i is the length of the irradiated area;

I is the distance from the input end of the OK to the irradiated area;

If the required pulse energy of the generator 7-t _i * P _gene will exceed the maximum minimum fracture energy for this type of organic matter, then in this case, the decisive device 5 generates several pulse sequences so that the energy of each of the pulses does not exceed the allowable. Under the influence of radiation pulses from the generator, the radiation-induced color centers in the OM will be destroyed, and its attenuation will decrease. If the growth rate of radiation-induced losses under the influence of ionizing radiation is less than the relaxation rate, the solver will generate pulses of shorter duration, and upon reaching a certain value of the total loss of organic matter, it will stop the generation of start-up pulses of the generators. Otherwise, the OM attenuation will increase and, upon reaching a certain value, the solver will issue a command to the indicator, signaling that the system is working at its limit value.

Thus, the system allows not only to reveal the fact of irradiation of the line with ionizing radiation, but also to increase its reliability by introducing optical radiation into the optical fiber, which destroys radiation-induced color centers.

Consider how in the proposed system unauthorized access to the cable and its mechanical damage are detected. It was experimentally established that if in a small area the guide shell of the OM is removed, or the OM is bent (in order to gain access to the radiation that carries the information), this will lead to changes in the reflectogram. A small “ledge” down will appear in its corresponding place, due to an increase in losses due to leakage from the core into the shell.

Therefore, the operator observing the display screen 26 DOR 4, will be able to detect this defect in the trace and determine the distance to it. In the same way, he will be able to detect a crack that has arisen in the core of OM. The only difference is that the crack will manifest itself in the form of a burst on the trace, because the intensity of the backscattered radiation, due to reflection at the ends of the crack, increases sharply compared to reflection on the inhomogeneities of the material. In addition to the visual, on the display screen of the OTDR 4, the analysis of the state of the OB is carried out by a resolver 5, which identifies the corresponding heterogeneities with the digital filters matched with them.

If the signal from the corresponding matched filter exceeds the signal from the other filters, then this indicates that the corresponding heterogeneity is detected on the trace: for example, a section with a removed shell or a crack.

In the case when the intruder tries to turn on in the mode of hard-to-detect relay with the inclusion of additional lengths of optical signals (Fig. 9) without access to key data and without scanning the input PPSDK 74 (since this is counteracted by LSI 59), he is not able to generate the necessary reflection conditions at the input of PPSNBK 71 or a request at a wavelength corresponding to the encryption gamut at the output of PPSNBK 73 because this information arrives at PPSNDK 73 and PPSNBK 71 at the moment when it should arrive already at PPSBKOV 70 and PPSDKOV 74, respectively. When analyzing the backscattered signal, obviously, a “reflecting object” will be detected. But, unlike other heterogeneities, the distance to the opposite end of the OM is known, and, therefore, the number of the element M of the transformed reflectogram array, which characterizes the burst level, is also known. Thus, the last portion of the trace obtained in PPSBK 70 will contain the burst value caused by the reflection of the scanning pulse from BO 52, which does not correspond to the gamma values of the encryption for the minimum permissible period of error-free operation (since in the encryption gamma, the values of the gamma alphabet are equally probable), which means that with

with a probability equal to the probability of not guessing the number of consecutive characters of the encryption gamma defined in the BCG 54, the intruder will be detected. This will lead to the operation of the BCG 54 and the cessation of the formation of the encryption gamma, and, consequently, the operation of the BCG 54 at the opposite end of the OB. In the opposite direction, the system will function similarly. Thus, the Simmons secret system model [7, 11] reduces to the Shannon secret system model [9] ie the probability of including an intruder as a repeater is reduced, and, consequently, the number and probability of realization of information security threats.

Therefore, the above branch (Fig. 8) will contain, after checking condition (2), additionally the following operations:

the condition is checked

j = M (3)

If condition (3) is satisfied, then this indicates that a burst of the scanning pulse reflected from the opposite end of the OB has been detected on the trace, and the condition is checked:

α _m -α ^** > 0 (4)

where α ^** is a predetermined value, which is determined as the arithmetic mean of two values of α _m , under the reflection conditions formed in BO 52 at the opposite end of the OM, corresponding to two possible values of the recognition gamma.

Otherwise, this means that a section with a removed shell or crack has been detected.

Depending on the fulfillment of condition (4), it is concluded what average reflection conditions for the last, sufficient to evaluate the trace (with the values of the request gamma and recognition corresponding to the current) period, were formed in BO 52 at the opposite end of the OB. The value of the proposed gamut is sent to BKG 54, in which the compliance with the real value coming from the BNP 58 is checked. If the estimated and real recognition gamma do not match, then

a conclusion is drawn about the mismatch of the length of the OM determined in the documentation, and, therefore, about the presence of hard-to-detect relay.

To exclude the possibility of preliminary scanning of the reflection conditions in BO 52, BIS 59 is used, in which the real gamma of the query and measured are verified, and the presence of the scanning signal is checked only on one of the two photodetectors 18, 19 of DOR 4. If these conditions are not met, a conclusion is drawn about the active actions the intruder by relaying information and a signal is generated in the BOVLS 55 about scanning the BO 52. To exclude the possibility of preliminary scanning, introducing a mismatch in the exchange process, the exact sync the lowering of the transceiver stations among themselves over the duplex channel for transmitting information by means of the BPG 50 and OG 51 units based on the redundant information circulating in the duplex channel and the signal about the moment of reception of the pulse.

If condition (3) is not fulfilled, the solver 5 generates a command that arrives at the signal-indicating device 27 of the reflectometer 4 about a local change in the characteristics of the OB of cable 11. In those cases when it is detected rather quickly (within a few minutes) that changes in time change in the attenuation of the cable section, a signal is generated that warns of irradiation of the line with ionizing radiation. In all cases, as soon as the resolving device 5 detects the heterogeneity, it generates a command to give an alert.

Analysis of changes in the state of the cable under the influence of external conditions is performed by the decisive device 5 in the same way as when determining the degree of impact of ionizing radiation on it. If the total loss in the cable exceeds a predetermined value, the deciding device 5 generates the appropriate command to supply the necessary signals to the indicator-indicator 27 of the reflectometer 4.

Thus, as the above description shows, the proposed system allows along with the transmission of information to monitor the status of the OK, with a greater probability of detecting unauthorized access,

identify emerging defects and external factors acting on it, determine the place of their occurrence and, at the same time, have increased reliability under the conditions of exposure to ionizing radiation.

Information sources

1. Butusov M.M., Wernick S.M., Galkin S.L. and etc.; Edited by V. Gomzin Fiber-optic transmission systems: Textbook for high schools. - M .: Radio and communication. - 1992 .-- 416 p.: Ill.

2. GOST 26814-86

3. Grigoryants VV, Chamrovsky Yu.K. Diagnostics of optical fibers by the method of backscattering in // Itogi Nauki i Tekhniki. Ser. Radio engineering. - 1982. - T. 29. - p. 47-78.

4. Grigoryants VV, Chamrovsky Yu.K., Isaev V.A., Shatrov A.D. Characteristics of backscattering in optical fibers // Quantum Electronics, 10, No. 4 (1983). - from 766-773.

5. Iorgachev DV, Bondarenko OV. Fiber optic cables and communication lines. - M .: Eco-Trends, 2002.

6. Kuzmin I.V., Kedrus V.A. Fundamentals of information theory and coding. Kiev, Vishka Shkola Publishing Association, 1977, 280 pp.

7. Messi, J. L. Introduction to modern cryptology // TIIER, t.76, No. 5, May 1988. - S.25-42.

8. Solonina A. I., Ulahovich D. A., Arbuzov S. M., Soloviev E. B., Guk I. I. The basics of digital signal processing. - SPb .: BHV-Petersburg, 2003 .-- 608 p.: Ill.

9. Shannon K. Communication Theory in Secret Systems // In the book: Works on the theory of information and cybernetics. - M .: il, 1963.

10. Barnoski J.K., Jensen S.M., "Fiber waveguides: A novel technique for investigation attenuation characteristics", Appl. Opt., Vol. 15, pp. 2112-2115, 1976

11. Simmons G.J. Autentication theory / coding theory in Advences in Cryptology, Proseedings of CRYPTO 84, G. R. Blackley and D. Chaum, Eds. Lecture Notes in Computer Science, No. 196. New York, NY: Springer, 1985, pp. 411-431.

Claims (2)

1. A multi-parameter fiber-optic information-diagnostic transmission system comprising a transmitter and a receiver connected by an optical cable, the transmitter comprising an information source whose output is connected to an input of an electron-optical converter, the output of which is connected to an optical cable through an optical signal input unit, the opposite end of which is optically connected to the photodetector of the information signal, a two-channel optical reflectometer operating at two wavelengths, the output to or connected to the second input of the optical signal input unit, a resolving device, a pulsed optical generator, and a pulse generating unit for starting the optical generator, the digital output of the reflectometer being connected to the input of the solving device, one of the outputs of which is connected to the control input of the OTDR, and the second output of the solving device is connected with the input of the formation of the start pulses of the pulse optical generator, the optical output of which is connected to the third input of the optical signal input unit, which additionally includes the identical fiber-optic information-diagnostic system for transmitting in the opposite direction with the transmission of information carried out at a different wavelength along the same optical fiber, and each of them contains a generator tuning block, a reference generator, a delay block, and reflection unit, in which case: the output and the first input of the generator tuning block are connected, respectively, to the input and the first output of the reference generator, the second and third inputs of the generator tuning block are connected, respectively, with the output of the photodetector and the output of the information receiver, and the second and third outputs of the reference generator are connected, respectively, with the second input of the resolving device and the second input of the electron-optical converter, in which changes have been made to control the generated optical signals, and, in addition to in addition, into the optical fiber between the OTDR with an improved algorithm for processing the reflected signal having a control circuit for the formation of scanning pulses from the resolver -keeping, and a block of input optical signals, to realize a spectral demultiplexer / multiplexer, further performing the functions of spectrally selective element having four output / input sequentially enabled reflection unit having an input connected to the output of delay unit connected input to an output of the decision unit. 2. The transmission system according to claim 1, characterized in that the gamma control unit, the block for determining inclusion in the communication line, the source of the gamma encryption, the converter for the gamma encryption, the block for the direction of transmission, the block for identifying the scan, the block for signaling an enable into a communication line, a key storage device and a station type storage device, and the output is connected in series with the input: output buffer memory, gamma control unit, line connection detection unit with monitor, gamma encryption source, gamma encryption converter, transmission direction block, scan identification block, and, in addition, the output of the scan identification block is connected to the second input of the communication inclusion determination unit, the second output of the communication inclusion determination block is connected to the input of the block signaling the connection to the communication line, the output of the key storage device is connected to the second input of the encryption gamma source, the output of the station-type storage device with the second input of the unit transmission direction, and the second output of the transmission direction block with the second input of the gamma control unit.