An information-driven fusion feature X-ray modulation and demodulation system and method

Abstract

A high-speed X-ray communication signal modulation device and method for information-driven characteristic X-rays, which modulates the information to be transmitted into a multi-level signal through an information-driven device, and simultaneously controls multiple lasers to drive photoelectric X-ray tubes to generate fused characteristic X-rays. After collimation and long-distance transmission, the fused characteristic X-rays are focused, detected, and time-synchronized at the receiving end. The fused characteristic X-rays are then demodulated using an intelligent demodulator to finally decode and restore the original information. The present invention uses multiple lasers to simultaneously drive multiple photocathodes to output fused characteristic X-rays, and uses an intelligent demodulation device at the receiving end to distinguish characteristic X-rays of various energies in the fused characteristic X-rays, exponentially increasing the number of code elements in signal transmission and realizing high-speed X-ray communication. The characteristic X-ray photons have high intensity, can reduce background noise interference, and have the characteristics of high communication rate and low bit error rate.

Description

Technical Field

[0001] The present invention belongs to the field of space communication technology, and in particular relates to an information-driven fusion characteristic X-ray modulation and demodulation device and method. Background Art

[0002] X-ray communication (XCOM) is a communication method that uses X-rays to transmit information, attaching information to the characteristic parameters of X-rays for transmission. It was first proposed by Dr. Keith Gendreau of NASA in 2007, who conducted communication experiments. When the X-ray energy is greater than 10 keV and the atmospheric pressure is less than 0.1 Pa, the X-ray penetration rate reaches almost 100%, meaning that X-rays can propagate in a vacuum without attenuation. Furthermore, X-rays used as carrier waves for space communications offer the following advantages: extremely large channel capacity and communication bandwidth, high confidentiality and strong anti-interference capabilities, and a compact size, light weight, and low power consumption. Therefore, XCOM is particularly suitable for deep space or interstellar communications.

[0003] In a currently proposed X-ray communication scheme, Dr. Keith Gendreau applies a signal to a UV LED and modulates the LED to generate photoelectrons, thereby controlling the generation of X-rays. The receiving end then converts the modulated X-rays into modulated electrical signals, enabling information transmission. Furthermore, Zhao Baosheng's team at the Xi'an Institute of Optics and Precision Mechanics, Chinese Academy of Sciences, has proposed a gate-controlled X-ray source. This approach, by controlling the gate voltage to control electron emission and thus the generation of X-rays, has enabled 64 kbit / s voice communication in a 6-meter-long vacuum tube.

[0004] In all of the above schemes, X-ray communication systems use intensity modulation, using the presence or absence of X-ray signals to transmit digital signals "0" and "1." At the receiving end, all X-rays within the detector's energy response range are considered valid signals. This is susceptible to the effects of cosmic rays and background X-rays in real space environments, resulting in a reduced signal-to-noise ratio and degraded communication performance. Furthermore, the limited number of code elements limits the communication rate.

[0005] Patent (application number 201810193985.2) proposed a magnetic field modulated X-ray source for space X-ray communication, which uses a magnetic field to control the X-ray source to produce different characteristic X-ray emissions; Patent (application number 201910805248.8) proposed an electric field modulated X-ray source, which uses an electric field to control the X-ray source to produce different characteristic X-ray emissions. In the above two schemes, by increasing the number of target materials and using characteristic X-rays of different energies as information carriers, the number of communication code elements is increased, and the signal-to-noise ratio is improved. However, there are still the following shortcomings: (1) In order to produce a large deflection of the electron beam, a large magnetic field and a large current are required to generate the magnetic field. The scheme uses a ferrite core. Under high frequency conditions, the increase in inductive reactance will affect the deflection performance and cannot achieve fast modulation; 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 subject to the speed of change of the electric field direction in the device. (2) Only one target material can be selected at a time to emit one characteristic X-ray, which does not fully utilize the different energy ranges of characteristic X-rays emitted by different target materials. The modulation and demodulation method of a signal modulation and demodulation device in space X-ray communication proposed in the patent (application number 201810193985.2) does not synchronize the signal time slot and the demodulation time slot. If the start and end times of the information time slot are not aligned with the start and end times of the demodulation time slot during demodulation at the receiving end, the characteristic X-ray photons carrying the signal in the previous signal time slot will be counted and demodulated by the next demodulation time slot, which will greatly increase the bit error rate of information transmission. Summary of the Invention

[0006] In response to the deficiencies in the prior art, the present invention provides an information-driven fusion characteristic X-ray modulation and demodulation device and method, which can utilize the characteristic X-ray energy differentiation properties more effectively for X-ray communication, and provide a signal modulation and demodulation method with faster modulation speed and lower bit error rate.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] 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 target materials, an X-ray collimating device, an X-ray focusing device, an X-ray detector and an intelligent demodulating device; the information driving device encodes the input initial information into a multi-channel level signal output, the level signal controls the plurality of lasers and drives the plurality of photoelectric X-ray tubes respectively, and modulates the fusion characteristic X-ray; the fusion characteristic X-ray is input into the X-ray collimating device, transmitted over a long distance in space, focused by the X-ray focusing device, detected and collected in the X-ray detector, and sent to the intelligent demodulating device after the signal time slot is matched one-to-one with the demodulation time slot via a time synchronization device; the code element information is identified and restored based on the intelligent demodulating device, and the initial information is finally decoded.

[0009] Preferably, the initial information is modulated into a digital signal by an information driving device and output in the form of multiple high and low levels, where the high level represents "1" and the low level represents "0", and all digital signals in a time slot are combined to represent a code element; the laser drives the corresponding photoelectric X-ray tube when triggered by a high level, and does not drive the corresponding photoelectric X-ray tube when triggered by a low level.

[0010] Preferably, the laser is a high-speed modulated laser with a modulation frequency of more than 100 MHz.

[0011] Preferably, the plurality of photoelectric X-ray tubes are each loaded with a different target material for emitting characteristic X-rays of different energies; the plurality of photoelectric X-ray tubes are combined together, and it is ensured that the end face of the cathode ring of each photoelectric X-ray tube is in the same plane, and the end face of each beryllium window is in the same plane, and the combined photoelectric X-ray tube is driven by a level signal to simultaneously emit multiple characteristic X-rays to converge into corresponding fused characteristic X-rays.

[0012] Preferably, the fused characteristic X-rays are formed by simultaneously emitting characteristic X-rays of different energy ranges generated by different target materials at the emission end and converging therefrom; each characteristic X-ray of energy represents a bit in a code element, and each fused characteristic X-ray represents a code element, that is, several lasers simultaneously drive several photoelectric X-ray tubes under the control of multiple level signals, and the emission / non-emission combination of several photoelectric X-ray tubes represents a code element at a moment.

[0013] Preferably, the X-ray detector only opens energy detection channels corresponding to characteristic X-rays, and counts the received fused characteristic X-ray photon distribution data.

[0014] Preferably, the time synchronization device can match the start time and end time of the signal time slot with the start time and end time of the demodulation time slot to avoid the characteristic photons of the previous signal time slot existing in the next demodulation time slot, or the characteristic photons of the next signal time slot existing in the previous demodulation time slot.

[0015] Preferably, multiple groups of sub-neural networks are designed based on error correction coding ECOC, and each group of sub-neural networks processes signals in parallel and is 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 the code element information corresponding to the fused characteristic X-rays of each time slot, and completes the demodulation of the fused characteristic X-ray signals.

[0016] In addition, the present invention also proposes an information-driven fusion feature X-ray modulation and demodulation method, which includes the following steps:

[0017] Step 1: modulate the initial information into multiple high and low level signal outputs through the information driving device.

[0018] Step 2: Multiple lasers are controlled by multi-level signals to simultaneously drive multiple photoelectric X-ray tubes of different target materials to generate fused characteristic X-rays, which are received at the receiving end of the X-ray detector after collimation and focusing.

[0019] In step 3, the receiving end of the X-ray detector opens the corresponding characteristic X-ray energy detection channel and calculates the distribution statistics of the received X-ray photons. A time synchronization device precisely aligns the information time slot with the demodulation time slot. Each sub-neural network within the intelligent demodulation device uses the preset ECOC coding rules to classify the current time slot statistics based on the X-ray photon distribution statistics, generating a set of classification result codes. The intelligent demodulation device calculates the Hamming distance between this classification result code and various ECOC codes to accurately identify the code element information corresponding to the fused characteristic X-rays in each time slot. Finally, decoding is performed to restore the original information.

[0020] The beneficial effects of the present invention are:

[0021] (1) The communication rate is fast. The limit of the modulation speed of the laser-driven photocathode to generate X-rays is only determined by the flight time of the electrons in the X-ray tube.

[0022] (2) Fusion of characteristic X-rays can make full use of the different properties of characteristic X-ray energy ranges of different materials, exponentially increase the number of code elements, and thus further improve the communication rate.

[0023] (3) Using characteristic X-rays as information carriers can reduce the impact of background noise on information restoration at the receiving end, improve the signal-to-noise ratio, and reduce the bit error rate of communication.

[0024] (4) To address the problem of mutual interference between characteristic X-rays in different time slots, a time synchronization device is added at the receiving end to align the information time slot with the demodulation time slot to reduce the bit error rate of communication. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the overall structure of an embodiment of the present invention;

[0026] Figure 2 1 is a schematic diagram of the structure of a photoelectric tube assembly according to an embodiment of the present invention;

[0027] Figure 3 is a schematic diagram of the 3D structure of a single photoelectric tube according to an embodiment of the present invention;

[0028] Figure 4 This is a schematic diagram of a single-tube structure according to an embodiment of the present invention;

[0029] Figure 5 This is the trajectory of electron acceleration in a tube according to an embodiment of the present invention;

[0030] Figure 6 This is a focus image on a target according to an embodiment of the present invention;

[0031] Figure 7 is a diagram of the focusing and accelerating electric field distribution according to an embodiment of the present invention;

[0032] Figure 8 This is an energy spectrum diagram of the fusion characteristic X-ray according to an embodiment of the present invention. DETAILED DESCRIPTION

[0033] The present invention will now be described in further detail with reference to the accompanying drawings.

[0034] like Figure 1 The signal modulation and demodulation system for space X-ray communication shown in the figure includes an information drive device, multiple high-speed modulated lasers, multiple photoelectric X-ray tubes with different target materials, an X-ray collimator, an X-ray focusing device, an X-ray detector, and an intelligent demodulator. The information drive device encodes the input initial information into multiple level signal outputs. The level signals control multiple lasers and drive multiple photoelectric X-ray tubes respectively, modulating them into fused characteristic X-rays. The fused characteristic X-rays are input into the X-ray collimator for long-distance transmission in space. After being focused by the X-ray focusing device, they are detected and collected by the X-ray detector. The signal time slot is matched to the demodulation time slot by a time synchronization device and then sent to the intelligent demodulator. The intelligent demodulator recognizes and restores the code element information, and finally decodes the original information.

[0035] The modulation and demodulation method using the system includes the following steps:

[0036] Step 1: The information driver modulates the input information into multiple high- and low-level signals, which are then fed into multiple lasers. The modulated high- and low-level signals, including high and low levels, represent "0" and "1," respectively, representing a bit in a symbol. The combination of all high- and low-level signals in a time slot represents a symbol. Under the control of these multiple level signals, the multiple lasers simultaneously drive multiple photoelectric X-ray tubes. The emission / non-emission patterns of these multiple photoelectric X-ray tubes represent a symbol at a given moment.

[0037] That is, when a laser receives a high level, it drives the light pipe to produce a characteristic X-ray. This single characteristic X-ray is part of the fused characteristic X-ray and represents one bit of the transmitted symbol in a time slot. At the demodulator, if this characteristic X-ray is present in the fused characteristic X-ray, it is decoded as a 1; if it is absent, it is decoded as a 0, representing one bit of the transmitted symbol.

[0038] Step 2: Multiple lasers, controlled by multiple level signals, simultaneously drive multiple photoelectric X-ray tubes with different target materials to output fused characteristic X-rays. In this embodiment, chromium, copper, gold, and molybdenum can be used as targets for the four photoelectric X-ray tubes. When the cathode-anode potential difference is 30V, the energy ranges for the maximum characteristic X-ray flux emitted by the four targets are: 5-6 KeV, 8-9 KeV, 9-10 KeV, and 17-18 KeV, respectively.

[0039] like Figures 2 to 4 As shown in the figure, the phototube is a hollow cylinder with a cathode ring and an anode ring at each end. A glass slide and a target are also placed on one side of the anode ring, and they are fixed together by a copper welding ring. The cathode ring contains a photocathode and a glass substrate. The photoelectrons generated by the photocathode are focused and accelerated in the tube and bombard the target. Their flight path is shown in the figure. Figure 5 As shown. The focus obtained on the target is as follows Figure 6 As shown. The focusing and accelerating electric field distribution diagram is shown Figure 7 shown.

[0040] The present invention compactly combines several phototubes with different target materials. In this embodiment, four phototubes are arranged in a square, ensuring that the end faces of each cathode ring and each beryllium window are coplanar. A laser simultaneously drives several of the four phototubes according to a level signal, emitting multiple characteristic X-rays that converge into corresponding fused characteristic X-rays. The characteristic X-rays corresponding to the selected multiple targets fall within different energy ranges, and the variety of fused characteristic X-rays increases exponentially with the number of targets.

[0041] Step 3: The receiving detector only opens the energy detection channels corresponding to the four characteristic X-rays and counts the received fused characteristic X-ray photon distribution data. The information time slot and the demodulation time slot are accurately overlapped by the time synchronization device. Each sub-neural network in the intelligent demodulation device completes training according to the preset ECOC coding rules. The statistical data of the four characteristic X-rays obtained by the four energy detection channels of the current time slot are input into each sub-neural network to obtain a set of classification result codes. The intelligent demodulation device calculates the Hamming distance between the classification result code and the various ECOC codes in the preset ECOC coding rules, finds the type of ECOC code with the smallest Hamming distance to the classification result code, and outputs the code element information corresponding to this type of ECOC code. Through the above process, it is possible to achieve the process from detecting the fused characteristic X-rays to accurately identifying the code element information corresponding to the fused characteristic X-rays in the current time slot. Finally, decoding is restored to the original information.

[0042] In the magnetic field modulated multi-target X-ray tube and electric field modulated multi-target X-ray tube used for space X-ray communication, electrons can only choose to bombard one target in each time slot, so the energy spectrum signal used to transmit information uses at most one characteristic X-ray energy region to carry information. Compared with the above two, the implementation scheme of this patent can select multiple of the four phototubes to hit different targets at the same time in one time slot to produce fused characteristic X-rays. Figure 8 The figure shows the fused X-ray spectrum of Cu and Cr. It clearly shows that there are two energy ranges with particularly prominent characteristic X-ray peaks: the Kα1 characteristic peak of Cr and the Kα1 characteristic peak of Cu. Thus, the embodiment of this patent can use multiple characteristic X-ray energy ranges within a single energy spectrum signal to carry information, thereby exponentially increasing the number of code elements and improving the communication rate.

[0043] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions based on the principles of the present invention are within the scope of protection of the present invention. It should be noted that for those skilled in the art, various improvements and modifications that do not depart from the principles of the present invention should be considered within the scope of protection of the present invention.

Claims

1. An information-driven fusion feature X-ray modulation and demodulation system, characterized in that: It includes an information drive device, several lasers, several photoelectric X-ray tubes with different target materials, an X-ray collimator, an X-ray focusing device, an X-ray detector, a time synchronization device and an intelligent demodulation device; The information driving device encodes the input initial information into a multi-channel level signal output, and the level signal controls a plurality of lasers and drives a plurality of photoelectric X-ray tubes respectively, modulating them into fusion characteristic X-rays; Fusion characteristic X-rays are formed by the simultaneous emission of characteristic X-rays of different energy ranges generated by different target materials at the transmitting end. Each characteristic X-ray of each energy represents a bit in a code element, and each fusion characteristic X-ray represents a code element. In other words, several lasers drive several photoelectric X-ray tubes simultaneously under the control of multi-level signals, and the emission / non-emission combination of several photoelectric X-ray tubes represents a code element of a time slot. The fusion characteristic X-ray is input into the X-ray collimation device, transmitted over a long distance in space, focused by the X-ray focusing device, detected and collected by the X-ray detector, and sent to the intelligent demodulation device after the signal time slot is matched one-to-one with the demodulation time slot via the time synchronization device; Based on the intelligent demodulation device, the code element information corresponding to the fused characteristic X-ray in each time slot is demodulated, and the initial information is finally decoded.

2. The information-driven fusion feature X-ray modulation and demodulation system according to claim 1, characterized in that: The initial information is modulated into a digital signal by an information driving device and output in the form of multiple high and low levels, where the high level represents "1" and the low level represents "0". The combination of all level signals in a time slot represents a code element; the laser drives the corresponding photoelectric X-ray tube when triggered by a high level, and does not drive the corresponding photoelectric X-ray tube when triggered by a low level.

3. The information-driven fusion feature X-ray modulation and demodulation system according to claim 2, characterized in that: The laser is a high-speed modulation laser, and the modulation frequency reaches above 100 MHz.

4. The information-driven fusion feature X-ray modulation and demodulation system according to any one of claims 1 to 3, characterized in that: The plurality of photoelectric X-ray tubes are each loaded with a different target material for emitting characteristic X-rays of different energies. The plurality of photoelectric X-ray tubes are combined together, and it is ensured that the end face of the cathode ring of each photoelectric X-ray tube is in the same plane, and the end face of each beryllium window is in the same plane. The combined photoelectric X-ray tube is driven by a level signal to simultaneously emit multiple characteristic X-rays to converge into corresponding fused characteristic X-rays.

5. The information-driven fusion feature X-ray modulation and demodulation system according to claim 1, characterized in that: The X-ray detector only opens energy detection channels corresponding to characteristic X-rays contained in the fusion characteristic X-rays, and counts the received fusion characteristic X-ray photon distribution data.

6. The information-driven fusion feature X-ray modulation and demodulation system according to claim 5, characterized in that: The time synchronization device matches the start and end times of the signal time slot with the start and end times of the demodulation time slot to avoid the characteristic photons of the previous signal time slot existing in the next demodulation time slot, or the characteristic photons of the next signal time slot existing in the previous demodulation time slot.

7. The information-driven fusion feature X-ray modulation and demodulation system according to claim 1, characterized in that: Based on the error correction code ECOC, multiple groups of sub-neural networks are designed. Each group of sub-neural networks processes signals in parallel and is 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 the code element information corresponding to the fused characteristic X-rays of each time slot and completes the demodulation of the fused characteristic X-ray signals.

8. An information-driven fusion feature X-ray modulation and demodulation method, characterized in that: The modulation and demodulation system according to any one of claims 1 to 7 comprises the following steps: Step 1: The initial information is modulated into multiple high and low level signal outputs by the information driving device; Step 2: Multiple lasers are controlled by multi-level signals to simultaneously drive multiple photoelectric X-ray tubes with different targets, generating characteristic X-rays that are a fusion of multiple X-rays. These X-rays are then collimated and focused and received by the X-ray detector. Step 3: The receiving end of the X-ray detector opens a characteristic X-ray energy detection channel and collects statistical data on the distribution of received X-ray photons. The information time slot is precisely aligned with the demodulation time slot through a time synchronization device. Each sub-neural network within the intelligent demodulation device classifies the current time slot statistics based on the X-ray photon distribution statistics according to a preset ECOC coding rule, obtaining a set 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, and finally decoding it to restore the original information.

Images