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CN-120415990-B - Carrier information modulation and demodulation method of controllable resonance magnetic pulse through-the-earth communication transmitter

CN120415990BCN 120415990 BCN120415990 BCN 120415990BCN-120415990-B

Abstract

The invention particularly relates to a carrier information modulation and demodulation method of a controllable resonance magnetic pulse through-the-earth communication transmitter, which comprises the steps of generating a magnetic pulse signal through a hardware topology of the magnetic pulse signal transmitter, wherein the hardware topology comprises a switch, a unidirectional on switch, a resonance capacitor and a solenoid, dividing the working period of an LC resonance system into four stages through the on and off of the control switch and the unidirectional on switch, generating discontinuous magnetic resonance signal pulses through dynamically adjusting the duration of each stage, designing an information modulation mechanism based on orthogonal code elements, generating waveforms of code elements 0 and 1, ensuring the orthogonality through verifying the autocorrelation and the cross correlation of the waveforms, and realizing information demodulation at a receiving end through calculating the cross correlation of the input discontinuous magnetic resonance signal, the code elements 0 and the code elements 1. The invention solves the contradiction that the existing ground penetrating system and modulation-demodulation method are difficult to consider between radiation efficiency and signal bandwidth.

Inventors

  • LI BO
  • XIANG SHIYANG
  • LI YUTING
  • XIE KAI
  • HUANG HE
  • XU HAN
  • ZHANG BAO

Assignees

  • 西安电子科技大学

Dates

Publication Date
20260508
Application Date
20250415

Claims (7)

  1. 1. A method for modulating and demodulating carrier information of a controllable resonant magnetic pulse through-the-earth communication transmitter, the method comprising: Generating a magnetic pulse signal through a hardware topology of a magnetic pulse signal transmitter, wherein the hardware topology comprises a first control switch K1, a second control switch K2, a unidirectional conduction switch Q1, a resonant capacitor C and a solenoid L; The working cycle of the LC resonance system is divided into four stages, namely energy initial storage, energy alternate transmission between a capacitor and an inductor, energy recovery and information loading windows by controlling the on and off of a first control switch K1, a second control switch K2 and a unidirectional conduction switch Q1; The whole control strategy dynamically adjusts the duration time of each stage through an algorithm according to the exciting current state and the bandwidth requirement fed back in real time; generating discontinuous magnetic resonance signal pulses by dynamically adjusting the duration of each stage; designing an information modulation mechanism based on the orthogonal code element, generating waveforms of the code element 0 and the code element 1, and ensuring orthogonality by verifying autocorrelation and cross correlation of the waveforms; At the receiving end, information demodulation is realized by calculating the cross correlation of the input discontinuous magnetic resonance signal with the code element 0 and the code element 1.
  2. 2. The method according to claim 1, wherein the duty cycle of the LC resonance system is divided into four phases by controlling the on and off of the first control switch K1 and the second control switch K2 and the unidirectional conduction switch Q1, specifically: the first stage, wherein a first controllable switch K1 is turned on, a second controllable switch K2 is turned off, an input voltage charges a resonant capacitor, and exciting current is zero; the second stage, wherein the first controllable switch K1 is turned off, the second controllable switch K2 is turned on, exciting current flows from the resonance capacitor to the resonance inductor, and energy is transferred from the capacitor to the inductor; the third stage, the first controllable switch K1 and the second controllable switch K2 are turned off, exciting current is fed back to the resonance capacitor from the resonance inductor and flows through the unidirectional conduction element Q1 to form a loop; And in the fourth stage, the first controllable switch K1 and the second controllable switch K2 are kept to be turned off, the unidirectional conduction element Q1 is turned off, one resonance period is completed, and a time window for information loading is formed.
  3. 3. The method of claim 1 wherein the waveform of symbol 0 is comprised of N magnetic pulse signals, each magnetic pulse signal having a period of The interval time of adjacent magnetic pulse signals is deltat, the waveform of the code element 1 is generated by phase shifting the waveform of the code element 0, and the phase shifting time is , wherein, Is the interval time of the sine signals of adjacent complete periods.
  4. 4. The method of claim 3, wherein verifying orthogonality of symbol 0 and symbol 1 comprises: calculating an autocorrelation function and a cross correlation function of the symbol 0 and the symbol 1; If the autocorrelation peak is significant and the cross correlation peak approaches zero, symbol 0 and symbol 1 are determined to be orthogonal.
  5. 5. The method according to claim 1, wherein the specific step of demodulating the information comprises: initializing a signal buffer, and defining a calculation window data length; Sequentially reading data from an input signal and updating a buffer; calculating the cross-correlation of the input signal window with the code element 0 and the code element 1; Comparing the cross correlation values, and decoding to be 0 or 1; And (5) circularly processing until all input signals are processed.
  6. 6. A method according to claim 3, wherein the interval time The following boundary conditions are satisfied: Minimum value is greater than minimum charge time of capacitor I.e. ; Minimum code rate with maximum value required by system Determination, i.e. Where N is the number of sine wave cycles.
  7. 7. The method of claim 6, wherein the minimum charge time of the capacitor Calculated by the following formula: For the capacitor voltage to rise from the initial value to 0.99 The time required, among others, Capacitor voltage 。

Description

Carrier information modulation and demodulation method of controllable resonance magnetic pulse through-the-earth communication transmitter Technical Field The invention relates to the technical field of through-the-earth communication, in particular to a carrier information modulation and demodulation method of a controllable resonant magnetic pulse through-the-earth communication transmitter, which is used for realizing information transmission between the ground and the underground or stratum. Background The earth penetrating communication technology starts from the beginning of the 20 th century, and mainly depends on the low-frequency electromagnetic wave and elastic wave communication technology in the early stage, but due to the limitations of narrow bandwidth, low transmission efficiency, poor anti-interference capability and the like, the modern communication requirements are gradually difficult to meet. In recent years, with the rapid development of digital signal processing technology and wireless communication technology, the through-the-earth communication technology gradually develops to the directions of high efficiency, low delay and high reliability, and particularly, the through-the-earth communication technology has a wide application prospect in the fields of mine rescue, underground facility monitoring, military communication and the like. At present, the main flow through-the-earth communication system is mainly realized based on three technologies, namely, firstly, low-frequency or extremely-low-frequency electromagnetic waves penetrate through a stratum to realize through-the-earth transmission, and secondly, low-frequency mechanical waves generated by mechanical elastic waves are used for realizing information transmission through penetrating through a rock mass. Thirdly, near field energy and information transmission are realized by a low frequency magnetic field based on the magnetic induction principle. In contrast, magnetic induction communication becomes an important technical direction in the field of through-the-earth communication by virtue of its excellent penetrating ability and anti-interference performance, and has made remarkable progress in system design, signal processing, modulation mechanism, and the like. Patent (CN 119560785A, parallel multi-coil magnetic antenna and magnetic transmission magnetic communication system), patent (CN 119135221A, a magnetic induction MIMO system inter-channel interference elimination method based on zero forcing precoding), patent (CN 118857273A, a magnetic induction signal detection and receiving method and system based on unmanned plane platform) respectively make progress in the aspects of transmitter antenna design, signal modulation and technical introduction. However, the existing magnetic induction technology adopts the traditional topology (source, power amplifier and antenna), and there are theoretical bottlenecks (such as contradiction between radiation efficiency and system bandwidth, contradiction between signal frequency and inverse proportion of physical size, etc.) which are difficult to break through. This not only makes it difficult to miniaturize the deep-penetrating transmission system, but also limits the flexible application of modulation techniques, resulting in a system that cannot support broadband information transmission. It should be noted that the information disclosed in the above background section is only for enhancing understanding of the background of the invention and thus may include information that does not form the prior art that is already known to those of ordinary skill in the art. Disclosure of Invention The invention provides a carrier information modulation-demodulation method of a controllable resonance magnetic pulse through-the-earth communication transmitter, which solves the contradiction that the existing through-the-earth system and modulation-demodulation method are difficult to consider between radiation efficiency and signal bandwidth. Other features and advantages of the invention will be apparent from the following detailed description, or may be learned by the practice of the invention. According to a first aspect of the present invention, there is provided a carrier information modulation-demodulation method of a controllable resonant magnetic pulse through-the-earth communication transmitter, the method comprising: The method comprises the following steps: Generating a magnetic pulse signal through a hardware topology of a magnetic pulse signal transmitter, wherein the hardware topology comprises a first control switch K1, a second control switch K2, a unidirectional conduction switch Q1, a resonant capacitor C and a solenoid L; the working cycle of the LC resonance system is divided into four stages, namely energy initial storage, energy alternate transmission between a capacitor and an inductor, energy recovery and information loading windows by controlling the on and off of