CN115967449A - Information-driven fusion characteristic X-ray modulation and demodulation system and method - Google Patents

Abstract

A high-speed X-ray communication signal modulation device and method for information-driven characteristic X-rays are characterized in that information to be transmitted is finally modulated into multi-channel level signals through an information driving device, a plurality of lasers are controlled to drive a photoelectric X-ray tube to generate fusion characteristic X-rays, after collimation and long-distance transmission, focusing, detection and time synchronization are carried out at a receiving end, then an intelligent demodulator is used for demodulating the fusion characteristic X-rays, and finally initial information is decoded and restored. The invention drives a plurality of photocathodes to output fusion characteristic X rays through a plurality of lasers simultaneously, and distinguishes the characteristic X rays with various energies in the fusion characteristic X rays through an intelligent demodulation device at a receiving end, thereby exponentially increasing the number of code elements in signal transmission and realizing high-speed X ray communication. The characteristic X-ray photon intensity is high, the background noise interference can be reduced, and the method has the characteristics of high communication rate and low error rate.

Description

Information-driven fusion characteristic X-ray modulation and demodulation system and method

Technical Field

The invention belongs to the technical field of space communication, and particularly relates to an information-driven fusion characteristic x-ray modulation and demodulation device and method.

Background

X-ray communication (XCOM) is a communication mode for transmitting information by using X-rays, and is a method for loading information onto characteristic parameters of the X-rays for transmission. It was first proposed by Dr. Keith Gendreau, prod.in 2007 by the United states aerospace agency, and communication experiments were performed. When the energy of the X-ray is more than 10kev and the atmospheric pressure is less than 0.1Pa, the transmittance of the X-ray can almost reach 100%, which means that the X-ray can propagate in a vacuum environment without attenuation. And the application of the X-ray as a carrier wave in space communication also has the following advantages: the system has the advantages of extremely large channel capacity and communication bandwidth, high confidentiality, strong anti-interference capability, small volume, light weight and low power consumption. XCOM is therefore particularly suitable for deep space or interplanetary communication.

In the currently proposed X-ray communication scheme, the Keith Gendreau doctor loads a signal on an ultraviolet LED, modulates the LED to modulate generated photoelectrons, thereby realizing control of generation of X-rays, and a receiving end converts the modulated X-rays into modulated electrical signals to realize information transmission. In addition, the Sian optical precision mechanical research institute Zhao Baosheng team of Chinese academy of sciences provides a grid-controlled X-ray source, and the electron emission is controlled through the control grid voltage, so that no X-ray is generated, and 64kbit/s voice communication is realized in a vacuum pipeline with the length of 6 meters.

In the scheme, the X-ray communication system adopts an intensity modulation mode, the transmission of digital signals '0' and '1' is realized through the existence/nonexistence of X-ray signals, all X-rays in the energy response range of a detector at a signal receiving end are considered as effective signals, and the effective signals are easily influenced by cosmic rays and background X-rays in a real space environment, so that the signal-to-noise ratio is reduced, and the communication performance is reduced. And the number of symbols is small, the communication rate is limited.

The patent (application number 201810193985.2) proposes a magnetic field modulation X-ray source for space X-ray communication, which uses a magnetic field to control the X-ray source to generate X-rays with different characteristics for emission; the patent application No. 201910805248.8 proposes an electric field modulated X-ray source that uses an electric field to control the X-ray source to produce different characteristic X-ray emissions. In the two schemes, the number of the target materials is increased, and the characteristic X-rays with different energies are used as information carriers, so that the number of communication code elements is increased, and the signal-to-noise ratio is increased. But has the following defects as before: (1) In the scheme, a ferrite magnetic core is adopted, so that the deflection performance is influenced by the increase of inductive reactance under the high-frequency condition, and the rapid modulation cannot be realized; the modulation speed of the electric field modulated X-ray source is higher than that of the magnetic field modulated X-ray source, but the modulation speed is still limited by the speed of change of the direction of the electric field within the device. (2) Only one target can be selected each time to emit one characteristic X-ray, and the different properties of the energy intervals of the characteristic X-rays emitted by different targets are not fully utilized. The patent (application number 201810193985.2) proposes a modulation and demodulation method for a modulation and demodulation device of signals in space X-ray communication, because no synchronization is performed on signal time slots and demodulation time slots, when a receiving end demodulates, if the starting time and the ending time of an information time slot are not aligned with the starting time and the ending time of the demodulation time slot one by one, the characteristic X-ray photons of a carried signal in the previous signal time slot are counted and demodulated by the next demodulation time slot, and the error rate of information transmission is greatly increased.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides an information-driven fusion characteristic X-ray modulation and demodulation device and method, which can apply the characteristic X-ray energy distinguishing property higher effect to X-ray communication and provide a signal modulation and demodulation mode with higher modulation speed and lower error rate.

In order to achieve the purpose, the invention adopts the following technical scheme:

an information-driven fusion characteristic X-ray modulation and demodulation system comprises an information driving device, a plurality of lasers, a plurality of photoelectric X-ray tubes with different targets, an X-ray collimation device, an X-ray focusing device, an X-ray detector and an intelligent demodulation device; the information driving device encodes input initial information into a plurality of paths of level signals to be output, and the level signals control a plurality of lasers and respectively drive a plurality of photoelectric X-ray tubes to be modulated into fused characteristic X-rays; inputting the fusion characteristic X-ray into an X-ray collimating device, carrying out long-distance transmission in space, carrying out detection collection in an X-ray detector after being focused by an X-ray focusing device, and sending signal time slots and demodulation time slots to an intelligent demodulation device after being in one-to-one correspondence by a time synchronization device; and identifying and restoring code element information based on the intelligent demodulation device, and finally decoding to obtain initial information.

Preferably, the initial information is modulated into a digital signal by the information driving device and output in the form of a plurality of high and low levels, wherein the high level represents "1" and the low level represents "0", and all the digital signals in one slot are combined to represent one symbol; the laser drives the corresponding photoelectric X-ray tube under high level triggering, and does not drive the corresponding photoelectric X-ray tube under low level triggering.

Preferably, the laser is a high-speed modulation laser, and the modulation frequency is above 100 MHz.

Preferably, the plurality of photoelectric X-ray tubes are respectively loaded with different targets and used for emitting characteristic X-rays with different energies; a plurality of photoelectric X-ray tubes are combined together, the end face of a cathode ring of each photoelectric X-ray tube is ensured to be on the same plane, the end face of each beryllium window is on the same plane, and the combined photoelectric X-ray tubes emit various characteristic X-rays simultaneously under the driving of level signals so as to converge into corresponding fusion characteristic X-rays.

Preferably, the fusion characteristic X-ray is formed by converging characteristic X-rays with different energy intervals generated by different targets after being simultaneously emitted by emitting ends; each energy characteristic X-ray represents one bit in one code element, each fusion characteristic X-ray represents one code element, namely, a plurality of lasers simultaneously drive a plurality of photoelectric X-ray tubes under the control of a multi-path level signal, and the code elements representing one moment are emitted/not emitted by the plurality of photoelectric X-ray tubes in a combined mode.

Preferably, the X-ray detector opens only the energy detection channels corresponding to the corresponding characteristic X-rays, and counts the received fused characteristic X-ray photon distribution data.

Preferably, the time synchronizer may correspondingly match the start time and the end time of the signal timeslot with the start time and the end time of the demodulation timeslot, so as to avoid that the characteristic photon of the previous signal timeslot exists in the next demodulation timeslot or the characteristic photon of the next signal timeslot exists in the previous demodulation timeslot.

Preferably, a plurality of groups of sub-neural networks are designed based on error correction coding ECOC, and the sub-neural networks process signals in parallel and are combined into an intelligent demodulation device; based on the classification results of the multiple groups of sub-neural networks, the intelligent demodulation device accurately identifies code element information corresponding to the fusion characteristic X-ray of each time slot, and the demodulation work of the fusion characteristic X-ray signal is completed.

In addition, the invention also provides an information-driven fusion characteristic X-ray modulation and demodulation method, which comprises the following steps:

step 1, modulating the initial information into a plurality of paths of high and low level signals through an information driving device and outputting the signals.

And 2, controlling a plurality of lasers by the multi-path level signals to simultaneously drive a plurality of photoelectric X-ray tubes of different targets to generate fusion characteristic X-rays, and receiving the fusion characteristic X-rays at a receiving end of the X-ray detector after collimation and focusing.

And step 5363, opening a corresponding characteristic X-ray energy detection channel at the receiving end of the X-ray detector of step 3,X, and counting the received X-ray photon distribution statistical data. Accurately superposing the information time slot and the demodulation time slot through a time synchronization device; and each sub-neural network in the intelligent demodulation device gives a classification result of the statistical data of the current time slot based on the X-ray photon distribution statistical data according to a preset ECOC coding rule to obtain a group of classification result codes. The intelligent demodulation device calculates the Hamming distance between the classification result code and various ECOC codes, thereby accurately identifying the code element information corresponding to the fusion characteristic X-ray of each time slot. The final decoding reverts back to the original information.

The beneficial effects of the invention are:

(1) The communication speed is fast, and the limit of the modulation speed of the X-ray generated by driving the photocathode with the laser only depends on the flight time of electrons in the X-ray tube.

(2) The fusion characteristic X-ray can fully utilize different properties of different material characteristic X-ray energy intervals, and exponentially improves the number of code elements, thereby further improving the communication speed.

(3) The characteristic X-ray is used as an information carrier, so that the influence of background noise on information recovery of a receiving end can be reduced, the signal-to-noise ratio is improved, and the error rate of communication is reduced.

(4) Aiming at the problem of mutual interference of characteristic X-rays in different time slots, a time synchronization device for aligning the information time slot with the demodulation time slot is added at a receiving end, so that the error rate of communication is reduced.

Drawings

FIG. 1 is a schematic overall structure of one embodiment of the present invention;

FIG. 2 is a schematic diagram of a structure of a photocell assembly according to one embodiment of the invention;

FIG. 3 is a schematic diagram of a single photocell 3D configuration according to one embodiment of the invention;

FIG. 4 is a schematic view of a single tube configuration of one embodiment of the present invention;

FIG. 5 is an in-tube electron acceleration flight trajectory according to one embodiment of the present invention;

FIG. 6 is a focus view on a target according to one embodiment of the present invention;

FIG. 7 is a focusing and accelerating electric field profile for one embodiment of the present invention;

FIG. 8 is an energy spectrum of fused feature x-rays of one embodiment of the present invention.

Detailed Description

The invention will now be described in further detail with reference to the accompanying drawing.

The system for modulating and demodulating signals in spatial X-ray communication shown in fig. 1 includes an information driving device, a plurality of high-speed modulation lasers, a plurality of different target photoelectric X-ray tubes, an X-ray collimating device, an X-ray focusing device, an X-ray detector and an intelligent demodulating device. The information driving device encodes input initial information into a plurality of paths of level signals to be output, and the level signals control a plurality of lasers and respectively drive a plurality of photoelectric X-ray tubes to be modulated into fused characteristic X-rays; inputting the fusion characteristic X-ray into an X-ray collimating device, carrying out long-distance transmission in space, carrying out detection and collection in an X-ray detector after being focused by an X-ray focusing device, and sending signal time slots and demodulation time slots to an intelligent demodulation device after being in one-to-one correspondence by a time synchronization device; and identifying and restoring code element information based on the intelligent demodulation device, and finally decoding to obtain initial information.

The modulation and demodulation method adopting the system comprises the following steps:

step 1: the information driving device modulates the input information into multiple high and low level signals and inputs the signals to the multiple lasers. The modulated high-low level signal comprises a high level and a low level which respectively represent '0' and '1' and are one bit in one code element; all high and low level signal combinations in one slot represent one symbol. The plurality of lasers simultaneously drive the plurality of photoelectric X-ray tubes under control of the multi-path level signal, and a symbol representing one time instant is transmitted/non-transmitted by the plurality of photoelectric X-ray tubes in combination.

That is, when a laser receives high level, the light pipe is driven to generate a characteristic X-ray, and the single characteristic X-ray is a part of the fused characteristic X-ray and is one bit of the transmission code element in a time slot. At the demodulation end, the fused characteristic X-ray contains the characteristic X-ray, and the fused characteristic X-ray is decoded into 1, and is not decoded into 0, so as to express one bit of information of the transmission code element.

Step 2: the multiple lasers simultaneously drive the multiple photoelectric X-ray tubes with different targets to output fusion characteristic X-rays under the control of the multi-path level signals. In this embodiment, chromium, copper, gold, and molybdenum may be used as targets loaded in the four photoelectric X-ray tubes. When the potential difference between the cathode and the anode is 30V, the characteristic X-ray energy intervals with the maximum emergent flux of the four targets are respectively as follows: 5-6KeV, 8-9KeV, 9-10KeV and 17-18 KeV.

As shown in fig. 2 to 4, the whole of the photoelectric tube is hollow and cylindrical, a cathode ring and an anode ring are respectively arranged at two ends of the photoelectric tube, and a glass slide and a target material are further arranged on one side of the anode ring and are fixedly connected through a copper welding ring. The cathode ring is internally provided with a photocathode and a glass substrate. Photoelectrons generated from the photocathode are focused and accelerated in the tube to bombard the target material, and the flight path of the photoelectrons is shown in FIG. 5. The resulting focus on the target is shown in fig. 6. The focusing and accelerating electric field profiles are shown in figure 7.

According to the invention, a plurality of photoelectric tubes of different targets are compactly combined together, and four photoelectric tubes are arranged in a square shape in the embodiment, so that the end face of each cathode ring is ensured to be on the same plane, and the end face of each beryllium window is ensured to be on the same plane. The laser drives several photoelectric tubes of the four photoelectric tubes simultaneously according to the level signal, and emits multiple characteristic X-rays simultaneously so as to converge into corresponding fusion characteristic X-rays. The energy intervals of the characteristic X-rays corresponding to the selected multiple targets are different, and the types of the fused characteristic X-rays are exponentially improved along with the increase of the number of the targets.

And step 3: and the detector at the receiving end only opens energy detection channels corresponding to the four characteristic X-rays, and counts the received photon distribution data of the fusion characteristic X-rays. And precisely coinciding the information time slot with the demodulation time slot through a time synchronization device. And each sub-neural network in the intelligent demodulation device completes training according to a preset ECOC coding rule. And inputting the statistical data of the four characteristic X-rays obtained by the four energy detection channels of the current time slot into each sub-neural network to obtain a group of classification result codes. The intelligent demodulation device finds the ECOC code with the minimum Hamming distance with the classification result code by calculating the Hamming distance between the classification result code and each ECOC code in the preset ECOC coding rule, and outputs the code element information corresponding to the ECOC code. Through the process, the code element information corresponding to the fusion characteristic X-ray of the current time slot can be accurately identified from the detection of the fusion characteristic X-ray. The final decoding reverts back to the original information.

The magnetic field modulation multi-target X-ray tube and the electric field modulation multi-target X-ray tube for space X-ray communication have the advantages that electrons can only selectively bombard one target in each time slot, so that the electrons are used for transmitting energy spectrum signals of information, and at most one characteristic X-ray energy area is used for carrying the information. Compared with the two methods, the embodiment of the patent can select a plurality of four photoelectric tubes to simultaneously hit different targets to generate the fused characteristic X-ray in one time slot. As shown in fig. 8, it is clear that the characteristic X-ray peak of two energy ranges is particularly distinct for the fused X-ray spectra of Cu and Cr, i.e., the K α 1 characteristic peak of Cr and the K α 1 characteristic peak of Cu. The embodiments of this sample patent can use the energy regions of various characteristic X-rays to carry information within one spectral signal, thereby exponentially increasing the number of symbols and increasing the rate of communication.

The above are only preferred embodiments of the present invention, and the scope of the present invention is not limited to the above examples, and all technical solutions that fall under the spirit of the present invention belong to the scope of the present invention. It should be noted that modifications and embellishments within the scope of the invention may be made by those skilled in the art without departing from the principle of the invention.

Claims (9)

1. An information-driven fusion characteristic X-ray modulation and demodulation system is characterized by comprising an information driving device, a plurality of lasers, a plurality of photoelectric X-ray tubes with different target materials, an X-ray collimation device, an X-ray focusing device, an X-ray detector, a time synchronization device and an intelligent demodulation device;

the information driving device encodes input initial information into a plurality of paths of level signals to be output, and the level signals control a plurality of lasers and respectively drive a plurality of photoelectric X-ray tubes to be modulated into fused characteristic X-rays; inputting the fusion characteristic X-ray into an X-ray collimating device, carrying out long-distance transmission in space, carrying out detection and collection in an X-ray detector after being focused by an X-ray focusing device, and sending signal time slots and demodulation time slots to an intelligent demodulation device after being in one-to-one correspondence by a time synchronization device; and demodulating code element information corresponding to the fusion characteristic X-ray in each time slot based on an intelligent demodulation device, and finally decoding to obtain initial information.

2. An information-driven fused feature X-ray modem system as claimed in claim 1 wherein the initial information is modulated into digital signals by the information-driving means and output in the form of multiple high and low levels, where a high level represents a "1" and a low level represents a "0", and all level signals in a time slot are combined to represent a symbol; the laser drives the corresponding photoelectric X-ray tube under high level triggering, and does not drive the corresponding photoelectric X-ray tube under low level triggering.

3. The information-driven fused-signature X-ray modem system of claim 2 wherein said laser is a high-speed modulated laser with a modulation frequency above 100 MHz.

4. An information-driven fused-signature X-ray modem system as claimed in any one of claims 1 to 3 wherein said plurality of photo-electric X-ray tubes are each loaded with a different target for emitting signature X-rays of different energies; a plurality of photoelectric X-ray tubes are combined together, the end face of a cathode ring of each photoelectric X-ray tube is ensured to be in the same plane, the end face of each beryllium window is in the same plane, and the combined photoelectric X-ray tubes emit various characteristic X-rays simultaneously under the driving of level signals so as to converge into corresponding fusion characteristic X-rays.

5. The information-driven fused-signature X-ray modem system as claimed in claim 4 wherein said fused signature X-rays are formed by converging different energy interval signature X-rays generated by different targets after emission at the emission end simultaneously; each energy characteristic X-ray represents one bit in one code element, each fusion characteristic X-ray represents one code element, namely, a plurality of lasers simultaneously drive a plurality of photoelectric X-ray tubes under the control of a multi-path level signal, and the code elements which are combined to represent one time slot are emitted/not emitted by the plurality of photoelectric X-ray tubes.

6. The information-driven fused feature X-ray modem system of claim 5, wherein said X-ray detector opens only energy detection channels corresponding to feature X-rays included in the fused feature X-rays, and counts the received fused feature X-ray photon distribution data.

7. An information driven fused feature X-ray modem system as claimed in claim 6 wherein said time synchronizer matches the start and end times of a signal slot with the start and end times of a demodulation slot to avoid the presence of a feature photon of a previous signal slot in a subsequent demodulation slot or a feature photon of a subsequent signal slot in a previous demodulation slot.

8. The information-driven fused feature X-ray modem system of claim 7 wherein, a plurality of sets of sub-neural networks are designed based on error correction coding ECOC, each set of sub-neural networks process signals in parallel and are combined into an intelligent demodulator; based on the classification results of the multiple groups of sub-neural networks, the intelligent demodulation device accurately identifies code element information corresponding to the fusion characteristic X-ray of each time slot, and the demodulation work of the fusion characteristic X-ray signal is completed.

9. An information-driven fused feature X-ray modulation and demodulation method is characterized by comprising the following steps:

step 1, modulating initial information into a plurality of paths of high and low level signals through an information driving device and outputting the signals;

step 2, controlling a plurality of lasers by a plurality of level signals to simultaneously drive a plurality of photoelectric X-ray tubes of different targets, generating characteristic X-rays fused by a plurality of X-rays, and receiving the characteristic X-rays by an X-ray detector after collimation and focusing;

step 3,X receiving end of ray detector opens characteristic X-ray energy detection channel, and counts received X-ray photon distribution statistical data; accurately superposing the information time slot and the demodulation time slot through a time synchronization device; each sub-neural network in the intelligent demodulation device gives a classification result of the statistical data of the current time slot based on the statistical data of the X-ray photon distribution according to a preset ECOC coding rule to obtain a group of classification result codes; the intelligent demodulation device accurately identifies code element information corresponding to the fusion characteristic X-ray of each time slot by calculating the Hamming distance between the classification result code and each ECOC code, and finally decodes and restores the code element information to the initial information.

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